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octal lna/vga/aaf/adc and crosspoint switch ad9271 rev. b information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ?2007C2009 analog devices, inc. all rights reserved. features 8 channels of lna, vga, aaf, and adc low noise preamplifier (lna) input-referred noise = 1.1 nv/hz @ 5 mhz typical, gain = 18 db spi-programmable gain = 14 db/15.6 db/18 db single-ended input; v in maximum = 400 mv p-p/ 333 mv p-p/250 mv p-p dual-mode active input impedance matching bandwidth (bw) > 70 mhz full-scale (fs) output = 2 v p-p differential variable gain amplifier (vga) gain range = ?6 db to +24 db linear-in-db gain control antialiasing filter (aaf) 3 rd -order butterworth cutoff programmable from 8 mhz to 18 mhz analog-to-digital converter (adc) 12 bits at 10 msps to 50 msps snr = 70 db sfdr = 80 db serial lvds (ansi-644, ieee 1596.3 reduced range link) data and frame clock outputs includes crosspoint switch to support continuous wave (cw) doppler low power, 150 mw per channel at 12 bits/40 msps (tgc) 90 mw per channel in cw doppler single 1.8 v supply (3.3 v supply for cw doppler output bias) flexible power-down modes overload recovery in <10 ns fast recovery from low power standby mode, <2 s 100-lead tqfp applications medical imaging/ultrasound automotive radar general description the ad9271 is designed for low cost, low power, small size, and ease of use. it contains eight channels of a variable gain amp- lifier (vga) with low noise preamplifier (lna); an antialiasing filter (aaf); and a 12-bit, 10 msps to 50 msps analog-to-digital converter (adc). each channel features a variable gain range of 30 db, a fully differential signal path, an active input preamplifier termination, a maximum gain of up to 40 db, and an adc with a conversion rate of up to 50 msps. the channel is optimized for dynamic performance and low power in applications where a small package size is critical. functional block diagram serial port interface reference fco+ fco? dco+ dco? lna lo-h losw-h li-h lg-h 12-bit adc serial lvds douth+ douth? lna lo-g losw-g li-g lg-g 12-bit adc serial lvds doutg+ doutg? lna lo-f losw-f li-f lg-f 12-bit adc serial lvds doutf+ doutf? lna lo-e losw-e li-e lg-e 12-bit adc serial lvds doute+ doute? lna lo-d losw-d li-d lg-d 12-bit adc serial lvds doutd+ doutd? lna lo-c losw-c li-c lg-c 12-bit adc serial lvds doutc+ doutc? lna lo-b losw-b li-b lg-b lna lo-a losw-a li-a lg-a 12-bit adc serial lvds doutb+ doutb? 12-bit adc serial lvds douta+ douta? avdd stby drvdd pdwn clk? clk+ sdio sclk csb rbias reft refb vref sense gain+ gain? cwd[5:0]+/? cwvdd switch array data rate multiplier 06304-001 aaf aaf aaf aaf aaf aaf aaf aaf ad9271 vga vga vga vga vga vga vga vga figure 1. the lna has a single-ended-to-differential gain that is selectable through the spi. the lna input noise is typically 1.2 nv/hz, and the combined input-referred noise of the entire channel is 1.4 nv/hz at maximum gain. assuming a 15 mhz noise bandwidth (nbw) and a 15.6 db lna gain, the input snr is roughly 86 db. in cw doppler mode, the lna output drives a transconductance amp that is switched through an 8 6 differential crosspoint switch. the switch is programmable through the spi.
ad9271 rev. b | page 2 of 60 table of contents features .............................................................................................. 1 applications ....................................................................................... 1 general description ......................................................................... 1 functional block diagram .............................................................. 1 revision history ............................................................................... 2 product highlights ........................................................................... 3 specifications ..................................................................................... 4 ac specifications .......................................................................... 4 digital specifications ................................................................... 7 switching specifications .............................................................. 8 adc timing diagrams ............................................................... 9 absolute maximum ratings .......................................................... 10 thermal impedance ................................................................... 10 esd caution ................................................................................ 10 pin configuration and function descriptions ........................... 11 equivalent circuits ......................................................................... 14 typical performance characteristics ........................................... 16 theory of operation ...................................................................... 20 ultrasound ................................................................................... 20 channel overview ...................................................................... 21 input overdrive .......................................................................... 23 cw doppler operation ............................................................. 24 tgc operation ........................................................................... 25 adc ............................................................................................. 27 clock input considerations ...................................................... 28 serial port interface (spi) .............................................................. 35 hardware interface ..................................................................... 35 memory map .................................................................................. 37 reading the memory map table .............................................. 37 reserved locations .................................................................... 37 default values ............................................................................. 37 logic levels ................................................................................. 37 applications information .............................................................. 41 design guidelines ...................................................................... 41 evaluation board ............................................................................ 42 power supplies ............................................................................ 42 input signals................................................................................ 42 output signals ............................................................................ 42 default operation and jumper selection settings ................. 43 quick start procedure ............................................................... 44 schematics and artwork ........................................................... 45 outline dimensions ....................................................................... 58 ordering guide .......................................................................... 58 revision history 5/09rev. a to rev. b changes to figure 27 ...................................................................... 17 changes to figure 40 and figure 41 ............................................. 21 changes to ordering guide .......................................................... 58 12/07rev. 0 to rev. a change to ac specifications text .................................................. 4 added input noise current ............................................................ 4 added noise figure .......................................................................... 4 changes to signal-to-noise ratio units ........................................ 4 changes to harmonic distortion units ........................................ 5 added endnote 3 .............................................................................. 6 changes to table 6 .......................................................................... 11 inserted figure 19 and figure 21 .................................................. 16 changes to figure 20 ...................................................................... 16 changes to theory of operation section .................................... 20 changes to figure 40 and figure 41 ............................................. 21 change to active impedance matching section ........................ 22 changes to lna noise section .................................................... 22 changes to figure 43 ...................................................................... 22 change to input overload protection section ........................... 23 changes to tgc operation section ............................................ 25 changes to gain control section ................................................. 26 changes to figure 52 ...................................................................... 26 change to table 11 ......................................................................... 33 changes to serial interface port (spi) section ........................... 35 changes to hardware interface section ...................................... 35 changes to reading the memory map table section ............... 37 added applications information and design guidelines sections ...................................................... 41 change to input signals section ................................................... 42 changes to figure 73 ...................................................................... 42 changes to table 16 ....................................................................... 55 6/07revision 0: initial version
ad9271 rev. b | page 3 of 60 the ad9271 requires a lvpecl-/cmos-/lvds-compatible sample rate clock for full performance operation. no external reference or driver components are required for many applications. the adc automatically multiplies the sample rate clock for the appropriate lvds serial data rate. a data clock (dco) for capturing data on the output and a frame clock (fco) trigger for signaling a new output byte are provided. powering down individual channels is supported to increase battery life for portable applications. there is also a standby mode option that allows quick power-up for power cycling. in cw doppler operation, the vga, aaf, and adc are powered down. the power of the tgc path scales with selectable speed grades. the adc contains several features designed to maximize flexibility and minimize system cost, such as a programmable clock, data alignment, and programmable digital test pattern generation. the digital test patterns include built-in fixed patterns, built-in pseudorandom patterns, and custom user-defined test patterns entered via the serial port interface. fabricated in an advanced cmos process, the ad9271 is available in a 16 mm 16 mm, rohs compliant, 100-lead tqfp. it is specified over the industrial temperature range of ?40c to +85c. product highlights 1. small footprint. eight channels are contained in a small, space-saving package. full tgc path, adc, and crosspoint switch contained within a 100-lead, 16 mm 16 mm tqfp. 2. low power of 150 mw per channel at 40 msps. 3. integrated crosspoint switch. this switch allows numerous multichannel configuration options to enable the cw doppler mode. 4. ease of use. a data clock output (dco) operates up to 300 mhz and supports double data rate (ddr) operation. 5. user flexibility. serial port interface (spi) control offers a wide range of flexible features to meet specific system requirements. 6. integrated third-order antialiasing filter. this filter is placed between the tgc path and the adc and is programmable from 8 mhz to 18 mhz.
ad9271 rev. b | page 4 of 60 specifications ac specifications avdd = 1.8 v, drvdd = 1.8 v, cwvdd = 3.3 v, 1.0 v internal adc reference, f in = 5 mhz, r s = 50 , lna gain = 15.6 db (6), aaf lpf cutoff = 1/3 f s , hpf cutoff = 700 khz, full temperature, unless otherwise noted. table 1. ad9271-25 ad9271-40 ad9271-50 parameter 1 conditions min typ max min typ max min typ max unit lna characteristics gain = 5/6/8 single-ended input to differential output 14/15.6/18 14/15.6/ 18 14/15.6/18 db single-ended input to single-ended output 8/9.6/12 8/9.6/12 8/9.6/12 db input voltage range, gain = 5/6/8 lna output limited to 2 v p-p differential output 400/333/250 400/333/250 400/333/250 mv p-p se 2 input common mode 1.4 1.4 1.4 v input resistance rfb = 200 50 50 50 rfb = 400 100 100 100 rfb = 15 15 15 k input capacitance li-x 15 15 15 pf ?3 db bandwidth 40 60 70 mhz input noise current, gain = 5/6/8 1.1 1.1 1.1 pa/hz input noise voltage, gain = 5/6/8 r s = 0 , rfb = 1.4/1.4/1.3 1. 3/1.2/1.1 1.3/1.2/1.1 nv/hz 1 db input compression point, gain = 5/6/8 v gain = 0 v 770/650/495 770/650/ 495 770/650/495 mv p-p noise figure active termination match r s = 50 , rfb = 200 6.7 6.7 6.7 db unterminated rfb = 4.9 4.4 4.2 db full-channel (tgc) characteristics aaf high-pass cutoff ?3 db dc/350/700 dc/350/700 dc/350/700 khz aaf low-pass cutoff ?3 db, programmable 1/3 f sample (8 to 18) 1/3 f sample (8 to 18) 1/3 f sample (8 to 18) mhz bandwidth tolerance 15 15 15 % group delay variation f = 1 to 18 mhz, gain = 0 v to 1 v 2 2 2 ns input-referred noise voltage lna gain = 5/6/8, rfb = 1.7/1.6/1.5 1.6/1.4/1. 3 1.6/1.4/1.2 nv/hz correlated noise ratio no signal, correlated/ uncorrelated ?30 ?30 ?30 db output offset aaf high pass = 700 khz ?50 +50 ?35 +35 ?35 +35 lsb signal-to-noise ratio (snr) f in = 5 mhz at ?7 dbfs v gain = 0 v 65.8 64.4 63.7 dbfs f in = 5 mhz at ?1 dbfs v gain = 1 v 62 59.7 59 dbfs
ad9271 rev. b | page 5 of 60 ad9271-25 ad9271-40 ad9271-50 parameter 1 conditions min typ max min typ max min typ max unit harmonic distortion second harmonic f in = 5 mhz at ?7 dbfs v gain = 0 v ?73 ?71 ?71 dbfs second harmonic f in = 5 mhz at ?1 dbfs v gain = 1 v ?80 ?72 ?68 dbfs third harmonic f in = 5 mhz at ?7 dbfs v gain = 0 v ?81 ?77 ?74 dbfs third harmonic f in = 5 mhz at ?1 dbfs v gain = 1 v ?65 ?63 ?66 dbfs two-tone imd3 (2 f1 ? f2) distortion f in1 = 5.0 mhz at ?7 dbfs, f in2 = 6.0 mhz at ?7 dbfs v gain = 1 v ?54.6 ?63.4 ?68.5 dbc channel-to-channel crosstalk ?70 ?70 ?70 db channel-to-channel crosstalk (over- range condition) 3 ?70 ?70 ?70 db overload recovery full tgc path, f in = 1 mhz to 10 mhz, gain = 0 v to 1 v 5 5 5 degrees gain accuracy 25c gain law confor- mance error 0 < v gain < 0.1 v +0.8 +0.8 +0.8 db 0.1 v < v gain < 0.9 v ?1.2 +1.2 ?1.2 +1.2 ?1.2 +1.2 db 0.9 v < v gain < 1 v ?1.2 ?1.2 ?1.2 db linear gain error v gain = 0.5 v, normalized for ideal aaf loss ?1.3 +1.3 ?1.3 +1.3 ?1.3 +1.3 db channel-to-channel matching 0.1 v < v gain < 0.9 v 0.2 0.2 0.2 db gain control interface normal operating range 0 1 0 1 0 1 v gain range 0 v to 1 v, normalized for ideal aaf loss 10 to 40 10 to 40 10 to 40 db scale factor 31.6 31.6 31.6 db/v response time 30 db change 350 350 350 ns cw doppler mode transconductance lna gain = 5/6/8 10/12/16 10/12/16 10/12/16 ma/v common mode cw doppler output pins 1.5 3.6 1.5 3.6 1.5 3.6 v input-referred noise voltage lna gain = 5/6/8, r s = 0 , rfb = 1.8 /1.7/1.5 1.7 /1.5/1.4 1.7 /1.5/1.3 nv/hz output dc bias per channel 2.4 2.4 2.4 ma maximum output swing per channel 2 2 2 ma p-p
ad9271 rev. b | page 6 of 60 ad9271-25 ad9271-40 ad9271-50 parameter 1 conditions min typ max min typ max min typ max unit power supply avdd 1.7 1.8 1.9 1.7 1.8 1.9 1.7 1.8 1.9 v drvdd 1.7 1.8 1.9 1.7 1.8 1.9 1.7 1.8 1.9 v cwvdd 3.0 3.3 3.6 3.0 3.3 3.6 3.0 3.3 3.6 i avdd full-channel mode 505 613 742 ma cw doppler mode with four channels enabled 136 160 170 ma i drvdd 46.7 48.7 50 ma total power dissipation (including output drivers) full-channel mode, no signal 993 1063 1190 1280 1425 1494 mw cw doppler mode with four channels enabled 192 216 224 mw power-down dissipation 4.5 4.5 4.5 mw standby power dissipation 101.7 112.5 120.6 mw power supply rejection ratio (psrr) 1 1 1 mv/v adc resolution 12 12 12 bits adc reference output voltage error (vref = 1 v) 20 20 20 mv load regulation @ 1.0 ma (vref = 1 v) 3 3 3 mv input resistance 6 6 6 k 1 see the an-835 application note, understanding high speed adc testing and evaluation , for a complete set of definitions and how these tests were completed. 2 se = single ended. 3 the overrange condition is specified as being 6 db more than the full-scale input range.
ad9271 rev. b | page 7 of 60 digital specifications avdd = 1.8 v, drvdd = 1.8 v, cwvdd = 3.3 v, 400 mv p-p differential input, 1.0 v internal adc reference, ain = ?0.5 dbfs, unles s otherwise noted. table 2. parameter 1 temperature min typ max unit clock inputs (clk+, clk?) logic compliance cmos/lvds/lvpecl differential input voltage 2 full 250 mv p-p input common-mode voltage full 1.2 v input resistance (differential) 25c 20 k input capacitance 25c 1.5 pf logic inputs (pdwn, stby, sclk) logic 1 voltage full 1.2 3.6 v logic 0 voltage full 0.3 v input resistance 25c 30 k input capacitance 25c 0.5 pf logic input (csb) logic 1 voltage full 1.2 3.6 v logic 0 voltage full 0.3 v input resistance 25c 70 k input capacitance 25c 0.5 pf logic input (sdio) logic 1 voltage full 1.2 drvdd + 0.3 v logic 0 voltage full 0 0.3 v input resistance 25c 30 k input capacitance 25c 2 pf logic output (sdio) 3 logic 1 voltage (i oh = 800 a) full 1.79 v logic 0 voltage (i ol = 50 a) full 0.05 v digital outputs (d+, d?), (ansi-644) 1 logic compliance lvds differential output voltage (v od ) full 247 454 mv output offset voltage (v os ) full 1.125 1.375 v output coding (default) offset binary digital outputs (d+, d?), (low power, reduced signal option) 1 logic compliance lvds differential output voltage (v od ) full 150 250 mv output offset voltage (v os ) full 1.10 1.30 v output coding (default) offset binary 1 see the an-835 application note, understanding high speed adc testing and evaluation , for a complete set of definitions and how these tests were completed. 2 specified for lvds and lvpecl only. 3 specified for 13 sdio pins sharing the same connection.
ad9271 rev. b | page 8 of 60 switching specifications avdd = 1.8 v, drvdd = 1.8 v, cwvdd = 3.3 v, 400 mv p-p differential input, 1.0 v internal adc reference, ain = ?0.5 dbfs, unles s otherwise noted. table 3. parameter 1 temp min typ max unit clock 2 maximum clock rate full 50 msps minimum clock rate full 10 msps clock pulse width high (t eh ) full 10.0 ns clock pulse width low (t el ) full 10.0 ns output parameters 2 , 3 propagation delay (t pd ) full 1.5 2.3 3.1 ns rise time (t r ) (20% to 80%) full 300 ps fall time (t f ) (20% to 80%) full 300 ps fco propagation delay (t fco ) full 1.5 2.3 3.1 ns dco propagation delay (t cpd ) 4 full t fco + (t sample /24) ns dco to data delay (t data ) 4 full (t sample /24) ? 300 (t sample /24) (t sample /24) + 300 ps dco to fco delay (t frame ) 4 full (t sample /24) ? 300 (t sample /24) (t sample /24) + 300 ps data-to-data skew (t data-max ? t data-min ) full 50 200 ps wake-up time (standby), v gain = 0.5 v 25c 1 s wake-up time (power-down) 25c 1 ms pipeline latency full 8 clock cycles aperture aperture uncertainty (jitter) 25c <1 ps rms 1 see the an-835 application note, understanding high speed adc testing and evaluation , for a complete set of definitions and how these tests were completed. 2 can be adjusted via the spi interface. 3 measurements were made using a part soldered to fr-4 material. 4 t sample /24 is based on the number of bits divided by 2, because the delays are based on half duty cycles.
ad9271 rev. b | page 9 of 60 adc timing diagrams dco? dco+ doutx? fco? fco+ ain clk? clk+ msb d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 d10 msb doutx+ n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 9 n ? 8 n ? 8 06304-00 n ? 1 n t data t frame t fco t pd t eh t a 2 t cpd t el figure 2. 12-bit data serial stream (default) dco? dco+ doutx? doutx+ fco? fco+ ain clk? clk+ lsb n ? 9 d0 n ? 9 d1 n ? 9 d2 n ? 9 d3 n ? 9 d4 n ? 9 d5 n ? 9 d6 n ? 9 d7 n ? 9 d8 n ? 9 d9 n ? 9 d10 n ? 9 d0 n ? 8 lsb n ? 8 n ? 1 t a n t data t frame t fco t pd t eh 06304-004 t cpd t el figure 3. 12-bit data serial stream, lsb first
ad9271 rev. b | page 10 of 60 absolute maximum ratings table 4. stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. parameter with respect to rating electrical avdd gnd ?0.3 v to +2.0 v drvdd gnd ?0.3 v to +2.0 v cwvdd gnd ?0.3 v to +3.9 v gnd gnd ?0.3 v to +0.3 v avdd drvdd ?2.0 v to +2.0 v digital outputs (doutx+, doutx?, dco+, dco?, fco+, fco?) gnd ?0.3 v to +2.0 v clk+, clk? gnd ?0.3 v to +3.9 v li-x lg-x ?0.3 v to +2.0 v lo-x lg-x ?0.3 v to +2.0 v losw-x lg-x ?0.3 v to +2.0 v cwdx?, cwdx+ gnd ?0.3 v to +3.9 v sdio, gain+, gain? gnd ?0.3 v to +2.0 v pdwn, stby, sclk, csb gnd ?0.3 v to +3.9 v reft, refb, rbias gnd ?0.3 v to +2.0 v vref, sense gnd ?0.3 v to +2.0 v environmental operating temperature range (ambient) ?40c to +85c storage temperature range (ambient) ?65c to +150c maximum junction temperature 150c lead temperature (soldering, 10 sec) 300c thermal impedance table 5. air flow velocity (m/s) ja 1 jb jc unit 0.0 20.3 c/w 1.0 14.4 7.6 4.7 c/w 2.5 12.9 c/w 1 ja for a 4-layer pcb with solid ground plane (simulated). exposed pad soldered to pcb. esd caution
ad9271 rev. b | page 11 of 60 li-f lg-f lo-f li-g lg-g lo-g avdd clk? clk+ avdd avdd avdd avdd li-e lg-e avdd avdd li-h lg-h lo-h avdd avdd losw-f losw- pin configuration and fu nction descriptions g losw-h 06304-005 ad9271 top view (not to scale) exposed paddle, pin 0 (bottom of package) pin 1 indicator 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 50 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 avdd 74 75 pdwn 73 stby 72 drvdd 71 douta+ 70 douta? 69 doutb+ 68 doutb? 67 doutc+ 66 doutc? 65 doutd+ 64 doutd? 63 fco+ 62 fco? 61 dco+ 60 dco? 59 doute+ 58 doute? 57 doutf+ 56 doutf? 55 doutg+ 54 doutg? 53 douth+ 52 douth? 51 drvdd avdd li-a lg-a losw-a li-b lg-b lo-b avdd sdio sclk csb avdd avdd li-c lg-c lo-c avdd avdd li-d lg-d avdd avdd lo-a losw-b losw-c losw- d lo-d cwd0? cwd0+ cw d1? cw d1+ cwd2? cwd2+ cwvdd gain? gain+ rbias sense vref refb reft avdd cwd3? cwd3+ cwd4? cwd4+ cwd5? cwd5+ lo-e losw-e figure 4. 100-lead tqfp pin configuration table 6. pin function descriptions pin no. name description 0 gnd ground (exposed paddle should be tied to a quiet analog ground) 3, 4, 9, 10, 15, 16, 21, 22, 25, 50, 54, 55, 60, 61, 66, 67, 72, 73, 92 avdd 1.8 v analog supply 26, 47 drvdd 1.8 v digital output driver supply 84 cwvdd 3.3 v analog supply 1 li-e lna analog input for channel e 2 lg-e lna ground for channel e 5 lo-f lna analog output for channel f 6 losw-f lna analog output complement for channel f 7 li-f lna analog input for channel f 8 lg-f lna ground for channel f 11 lo-g lna analog output for channel g 12 losw-g lna analog output complement for channel g 13 li-g lna analog input for channel g 14 lg-g lna ground for channel g 17 lo-h lna analog output for channel h
ad9271 rev. b | page 12 of 60 pin no. name description 18 losw-h lna analog output complement for channel h 19 li-h lna analog input for channel h 20 lg-h lna ground for channel h 23 clk? clock input complement 24 clk+ clock input true 27 douth? adc h digital output complement 28 douth+ adc h digital output true 29 doutg? adc g digital output complement 30 doutg+ adc g digital output true 31 doutf? adc f digital output complement 32 doutf+ adc f digital output true 33 doute? adc e digital output complement 34 doute+ adc e digital output true 35 dco? data clock digital output complement 36 dco+ data clock digital output true 37 fco? frame clock digital output complement 38 fco+ frame clock digital output true 39 doutd? adc d digital output complement 40 doutd+ adc d digital output true 41 doutc? adc c digital output complement 42 doutc+ adc c digital output true 43 doutb? adc b digital output complement 44 doutb+ adc b digital output true 45 douta? adc a digital output complement 46 douta+ adc a digital output true 48 stby standby power-down 49 pdwn full power-down 51 sclk serial clock 52 sdio serial data input/output 53 csb chip select bar 56 lg-a lna ground for channel a 57 li-a lna analog input for channel a 58 losw-a lna analog output complement for channel a 59 lo-a lna analog output for channel a 62 lg-b lna ground for channel b 63 li-b lna analog input for channel b 64 losw-b lna analog output complement for channel b 65 lo-b lna analog output for channel b 68 lg-c lna ground for channel c 69 li-c lna analog input for channel c 70 losw-c lna analog output complement for channel c 71 lo-c lna analog output for channel c 74 lg-d lna ground for channel d 75 li-d lna analog input for channel d 76 losw-d lna analog output complement for channel d 77 lo-d lna analog output for channel d 78 cwd0? cw doppler output complement for channel 0 79 cwd0+ cw doppler output true for channel 0 80 cwd1? cw doppler output complement for channel 1 81 cwd1+ cw doppler output true for channel 1 82 cwd2? cw doppler output complement for channel 2 83 cwd2+ cw doppler output true for channel 2 85 gain? gain control voltage input complement
ad9271 rev. b | page 13 of 60 pin no. name description 86 gain+ gain control voltage input true 87 rbias external resistor to set th e internal adc core bias current 88 sense reference mode selection 89 vref voltage reference input/output 90 refb differential reference (negative) 91 reft differential reference (positive) 93 cwd3? cw doppler output complement for channel 3 94 cwd3+ cw doppler output true for channel 3 95 cwd4? cw doppler output complement for channel 4 96 cwd4+ cw doppler output true for channel 4 97 cwd5? cw doppler output complement for channel 5 98 cwd5+ cw doppler output true for channel 5 99 lo-e lna analog output for channel e 100 losw-e lna analog output complement for channel e
ad9271 rev. b | page 14 of 60 li-x, lg-x 15k ? equivalent circuits avdd v cm 06304-073 figure 5. equivalent lna input circuit lo-x, losw-x 10 ? 06304-075 avdd figure 6. equivalent lna output circuit 10 ? 10k? 10k? clk? 10? 1.25v clk+ 06304-007 figure 7. equivalent clock input circuit sdio 350 ? 30k? 06304-008 a vdd figure 8. equivalent sdio input circuit dr v dd drgnd doutx? doutx+ v v v v 0 6304-009 figure 9. equivalent digital output circuit s clk or pdwn or stby 30k ? 1k ? 06304-010 figure 10. equivalent sclk input circuit
ad9271 rev. b | page 15 of 60 100? rbias avdd figure 11. equivale nt rbias circuit csb 70k ? 1k? a v dd 06304-011 06304 -012 figure 12. equivalent csb input circuit sense 1k? 06304 -013 figure 13. equivalent sense circuit vref 6k ? 0 6304 -014 avdd figure 14. equivalent vref circuit gain+ 50 ? 06304-074 figure 15. equivalent gain+ input circuit g ain? +0.5v 40k ? 06304-112 figure 16. equivalent gain? input circuit c wdx+, cwdx? 10 ? 06304-076 figure 17. equivalent cwdx output circuit
ad9271 rev. b | page 16 of 60 ?2.0 0630 v gain (v) typical performance characteristics f sample = 50 msps, f in = 5 mhz, lpf = 1/3 f sample , hpf = 700 khz, lna gain = 6. 2.0 1.0 1.5 ?1.0 ?0.5 0 0.5 ?1.5 4-019 absolute error (db) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 +85c +25c ?40c figure 18. gain error vs. v gain at three temperatures 20 10 4-120 percent of units (%) 18 16 14 12 8 6 4 2 ?1.0 ?0.6 0630 gain error (db) 0 ?0.8 ?0.4 ?0.2 0 0.40.2 0.6 0.8 1.0 sample size = 720 channels figure 19. gain error histogram with v gain = 0.1 v 06 gain error (db) ?1.0 ?0.9 ?0.8 ?0.7 ?0.6 ?0.5 ?0.4 ?0.3 ?0.2 ?0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 304-116 percent of units (%) 16 14 12 10 8 6 4 2 sample size = 720 channels figure 20. gain error histogram with v gain = 0.5 v 25 0 ?1.0 ?0.6 06304-121 gain error (db) percent of units (%) 20 15 10 5 ?0.8 ?0.4 ?0.2 0 0.40.2 0.6 0.8 1.0 sample size = 720 channels figure 21. gain error histogram with v gain = 0.9 v 06304-118 percent of units (%) channel-to-channel gain matching (db) 0 30 25 20 15 10 ?1.25 ?1.00 ?0.75 ?0.50 ?0.25 0 0.25 0.50 0.75 1.00 1.25 5 figure 22. gain match histogram for v gain = 0.2 v 06304-117 percent of units (%) channel-to-channel gain matching (db) 0 30 25 20 15 10 ?1.25 ?1.00 ?0.75 ?0.50 ?0.25 0 0.25 0.50 0.75 1.00 1.25 5 figure 23. gain match histogram for v gain = 0.8 v
ad9271 rev. b | page 17 of 60 06304-022 codes number of hits ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 5 0 200000 06304-023 codes ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 5 0 400000 600000 800000 1000000 1200000 1400000 1600000 1800000 2000000 figure 24. output-referred noise histogram with v gain = 0.0 v number of hits 200000 400000 600000 800000 1000000 1200000 figure 25. output-referred noise histogram with v gain = 1.0 v 06304-025 frequency (mhz) 0 5 10 15 20 25 0 0.5 input-referred noise (nv/ hz) 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 lna gain = 5 lna gain = 8 lna gain = 6 figure 26. short-circuit, inpu t-referred noise vs. frequency 06304-021 output-referred noise (dbfs/ hz) v gain (v) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ?140 ?139 ?138 ?137 ?136 ?135 ?134 ?133 ?132 ? 131 lna gain = 5 lna gain = 6 lna gain = 8 figure 27. short-circuit, output-referred noise vs. v gain 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 06304-020 snr/sinad v gain (v) 59.5 60.0 60.5 61.0 61.5 62.0 62.5 63.0 63.5 64.0 snr (dbfs) sinad (dbfs) figure 28. snr/sinad vs. v gain , ain = ?6.5 dbfs 06304-024 input-referred noise (nv/ hz) temperature (c) ?40 ?20 0 20 40 60 80 1.40 1.45 1.50 1.55 1.60 1.65 1.70 figure 29. short-circuit, input- referred noise vs. temperature
ad9271 rev. b | page 18 of 60 0 ?15 ?10 ?5 ?25 ?20 ?30 fundamental (dbfs) ?35 ?40 0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 06304-030 frequency (mhz) ?3db line (1/3) 50msps (1/3) 40msps (1/3) 25msps figure 30. antialiasing filter (aaf) pass-band response, no hpf applied 300 50 100 150 200 250 group delay (ns) 0 0.1 1 10 100 06304-033 analog input frequency (mhz) v gain = 0v v gain = 1.0v v gain = 0.5v figure 31. antialiasing filter (aaf) group delay response 06304-028 f in (mhz) 2 4 6 8 10121416 ?85 second harmonic (dbfs) ?80 ?75 ?70 ?65 ?60 ?55 ? 50 v gain = 0.2v v gain = 0.5v v gain = 1v figure 32. second-order harmonic distortion vs. frequency, ain = ?0.5 dbfs 06304-029 third harmonic (dbfs) f in (mhz) 2 4 6 8 1012141 ?85 ?80 ?75 ?70 ?65 ?60 ?55 6 ? 50 v gain = 0.2v v gain = 1v v gain = 0.5v figure 33. third-order harmonic distortion vs. frequency, ain = ?0.5 dbfs 06304-114 second harmonic (dbfs) adc output level (dbfs) ?110 ? 40 ?50 ?60 ?70 ?80 ?90 ?100 ?4 0 0 ?5 ?10 ?15 ?20 ?25 ?3 0 ?35 v gain = 0v v gain = 0.5v v gain = 1v figure 34. second-order harmonic distortion vs. adc output level 06304-115 third harmonic (dbfs) adc output level (dbfs) ?110 ? 40 ?50 ?60 ?70 ?80 ?90 ?100 ?4 0 0 ?5 ?10 ?15 ?20 ?25 ?3 0 ?35 v gain = 0v v gain = 0.5v v gain = 1v figure 35. third-order harmonic distortion vs. adc output level
ad9271 rev. b | page 19 of 60 ?110 ?100 ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 2.3mhz and 3.5mhz 5mhz and 6mhz 8mhz and 10.3mhz 0.2 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 06304-106 v gain (v) imd3 (dbfs) ain1 = ain2 = ?7dbfs figure 36. imd3 vs. v gain ?110 ?100 ?60 ?20 ?15 ?10 ?5 ?25?30?35?40?45 ?50 ?55 06304-107 input amplitude (dbfs) ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 imd3 (dbfs) v gain = 1v v gain = 0.5v v gain = 0v f1 = 5mhz f2 = 6mhz figure 37. imd3 vs. amplitude ?120 ?100 ?80 ?60 ?40 ?20 0 02 20 15 10 5 06304-108 amplitude (dbfs) frequency (mhz) 5 ain1 = ain2 = ?7dbfs f1 = 5mhz f2 = 6mhz imd2 = ?70.59dbc imd3 = ?64.45dbc v gain =1v figure 38. typical imd3 and imd2 performance
ad9271 rev. b | page 20 of 60 theory of operation ultrasound the primary application for the ad9271 is medical ultrasound. figure 39 shows a simplified block diagram of an ultrasound system. a critical function of an ultrasound system is the time gain control (tgc) compensation for physiological signal attenuation. because the attenuation of ultrasound signals is exponential with respect to distance (time), a linear-in-db vga is the optimal solution. key requirements in an ultrasound signal chain are very low noise, active input termination, fast overload recovery, low power, and differential drive to an adc. because ultrasound machines use beam-forming techniques requiring large binary- weighted numbers (for example, 32 to 512) of channels, the lowest power at the lowest possible noise is of key importance. most modern machines use digital beam forming. in this technique, the signal is converted to digital format immediately following the tgc amplifier, and then beam forming is accomplished digitally. the adc resolution of 12 bits with up to 50 msps sampling satisfies the requirements of both general-purpose and high- end systems. power consumption and low cost are of primary importance in low-end and portable ultrasound machines, and the ad9271 is designed for these criteria. for additional information regarding ultrasound systems, refer to how ultrasound system considerations influence front-end component choice , analog dialogue , volume 36, number 3, mayCjuly 2002, and the ad9271a revolutionary solution for portable ultrasound, analog dialogue , volume 41, number 7, july 2007. tx h v beam former central control rx beam former (b and f modes) color doppler (pw) processing (f mode) image and motion processing (b mode) spectral doppler processing mode display audio output tx beam former cw (analog) beam former amps multichannels transducer array 128, 256, etc., elements bidirectional cable hv mux/ demux t/r switches 06304-077 ad9271 aaf vga adc lna cw figure 39. simplified ultrasound system block diagram
ad9271 rev. b | page 21 of 60 lna li-x lg-x lo-x doutx+ doutx? cs t/r switch clg cfb rfb2 csh gain interpolator losw-x rfb1 to switch array g m cdwx+ cdwx? attenuator ?30db to 0db 12-bit pipeline adc serial lvds +24db gain? 06304-071 aaf gain+ ad9271 transduce r figure 40. simplified block diagram of a single channel channel overview each channel contains both a tgc signal path and a cw doppler signal path. common to both signal paths, the lna provides user- adjustable input impedance termination. the cw doppler path includes a transconductance amplifier and a crosspoint switch. the tgc path includes a differential x-amp? vga, an antialiasing filter, and an adc. figure 40 shows a simplified block diagram with external components. the signal path is fully differential throughout to maximize signal swing and reduce even-order distortion; however, the lna is designed to be driven from a single-ended signal source. low noise amplifier (lna) good noise performance relies on a proprietary ultralow noise lna at the beginning of the signal chain, which minimizes the noise contribution in the following vga. active impedance control optimizes noise performance for applications that benefit from input impedance matching. a simplified schematic of the lna is shown in figure 41 . li-x is capacitively coupled to the source. an on-chip bias generator establishes dc input bias voltages of around 1.4 v and centers the output common-mode levels at 0.9 v (vdd/2). a capacitor, c lg , of the same value as the input coupling capacitor, c s , is connected from the lg-x pin to ground. li-x cs clg cfb csh lg-x lo-x losw-x vcm vcm vo+ vo? rfb1 rfb2 06304-101 t/r switch tran sducer avdd2 figure 41. simplifi ed lna schematic the lna supports differential output voltages as high as 2 v p-p with positive and negative excursions of 0.5 v from a common- mode voltage of 0.9 v. the lna differential gain sets the maximum input signal before saturation. one of three gains is set through the spi. the corresponding input full scale for the gain settings of 5, 6, or 8 is 400 mv p-p, 333 mv p-p, and 250 mv p-p, respectively. overload protection ensures quick recovery time from large input voltages. because the inputs are capacitively coupled to a bias voltage near midsupply, very large inputs can be handled without interacting with the esd protection. low value feedback resistors and the current-driving capability of the output stage allow the lna to achieve a low input-referred noise voltage of 1.2 nv/hz. this is achieved with a current consumption of only 16 ma per channel (30 mw). on-chip resistor matching results in precise single-ended gains, which are critical for accurate impedance control. the use of a fully differential topology and negative feedback minimizes distortion. low hd2 is particularly important in second-harmonic ultrasound imaging applications. differential signaling enables smaller swings at each output, further reducing third-order distortion. active impedance matching the lna consists of a single-ended voltage gain amplifier with differential outputs and the negative output externally available. for example, with a fixed gain of 6 (15.6 db), an active input termination is synthesized by connecting a feedback resistor between the negative output pin, lo-x, and the positive input pin, li-x. this technique is well known and results in the input resistance shown in equation 1: ) 2 1( a r r fb in + = (1) where a /2 is the single-ended gain or the gain from the li-x inputs to the lo-x outputs.
ad9271 rev. b | page 22 of 60 because the amplifier has a gain of 6 from its input to its differential output, it is important to note that the gain a/2 is the gain from pin li-x to pin lo-x, and it is 6 db less than the gain of the amplifier, or 9.6 db (3). the input resistance is reduced by an internal bias resistor of 15 k in parallel with the source resistance connected to pin li-x, with pin lg-x ac grounded. equation 2 can be used to calculate the needed r fb for a desired r in , even for higher values of r in . + = k15|| )31( fb in r r (2) for example, to set r in to 200 , the value of r fb is 845 . if the simplified equation (equation 2) is used to calculate r in , the value is 190 , resulting in a gain error less than 0.5 db. some factors, such as the presence of a dynamic source resistance, might influence the absolute gain accuracy more significantly. at higher frequencies, the input capacitance of the lna needs to be considered. the user must determine the level of matching accuracy and adjust r fb accordingly. the bandwidth (bw) of the lna is about 70 mhz. ultimately the bw of the lna limits the accuracy of the synthesized r in . for r in = r s up to about 200 , the best match is between 100 khz and 10 mhz, where the lower frequency limit is determined by the size of the ac-coupling capacitors, and the upper limit is determined by the lna bw. furthermore, the input capacitance and r s limit the bw at higher frequencies. figure 42 shows r in vs. frequency for various values of r fb . 06304-10 10 100k 1m 10m 50m frequency (hz) 5 100 1k input impedance ( ? ) r s = 50 ? , r fb = 200 ? , c sh = 70pf r s = 100 ? , r fb = 400 ? , c sh = 20pf r s = 200 ? , r fb = 800 ? r s = 500 ? , r fb = 2k ? figure 42. r in vs. frequency for various values of r fb (effects of r sh and c sh are also shown) note that at the lowest value, 50 , in figure 42 , r in peaks at frequencies greater than 10 mhz. this is due to the bw roll-off of the lna, as mentioned previously. however, as can be seen for larger r in values, parasitic capacitance starts rolling off the signal bw before the lna can produce peaking. c sh further degrades the match; therefore, c sh should not be used for values of r in that are greater than 100 . table 7 lists the recommended values for r fb and c sh in terms of r in . c fb is needed in series with r fb because the dc levels at pin lo-x and pin li-x are unequal. table 7. active termination external component values lna gain r in () r fb () minimum c sh (pf) b (mhz) 5 50 175 90 49 6 50 200 70 59 8 50 250 50 73 5 100 350 30 49 6 100 400 20 59 8 100 500 10 73 5 200 700 n/a 49 6 200 800 n/a 49 8 200 1000 n/a 49 lna noise the short-circuit noise voltage (input-referred noise) is an important limit on system performance. the short-circuit noise voltage for the lna is 1.2 nv/hz or 1.4 nv/hz (at 15.6 db lna gain), including the vga noise. these measurements, which were taken without a feedback resistor, provide the basis for calculating the input noise and noise figure (nf) performance of the configurations shown in figure 43 . figure 44 and figure 45 are simulations of noise figure vs. r s results using these config- urations and an input-referred noise voltage of 4 nv/hz for the vga. unterminated (r fb = ) operation exhibits the lowest equivalent input noise and noise figure. figure 45 shows the noise figure vs. source resistance rising at low r s where the lna voltage noise is large compared with the source noiseand at high r s due to the noise contribution from r fb . the lowest nf is achieved when r s matches r in . v out unterminated + ? v in r in r s v out resistive termination + ? v in r in r s r s v out active impedance match + ? v in r in r fb r fb 1 + a/2 r s r in = 06304-104 figure 43. input configurations
ad9271 rev. b | page 23 of 60 0 06304-103 noise figure (db) 2 4 6 8 10 12 14 16 10 100 1000 r s ( ? ) unterminated resistive termination active termination figure 44. noise figure vs. r s for resistive termination, active termination matched, and unterminated inputs, v gain = 1 v, 15.6 db lna gain 06304-1 0 10 100 1000 r s ( ? ) 02 2 4 6 8 10 12 14 16 noise figure (db) r in = 50 ? r in = 100 ? r in = 75 ? r = 200 ? in unterminated figure 45. noise figure vs. r s for various fixed values of r in , active termination matched inputs, v gain = 1 v, 15.6 db lna gain the primary purpose of input impedance matching is to improve the transient response of the system. with resistive termination, the input noise increases due to the thermal noise of the matching resistor and the increased contribution of the lnas input voltage noise generator. with active impedance matching, however, the contributions of both are smaller (by a factor of 1/(1 + lna gain)) than they would be for resistive termination. figure 44 shows the relative noise figure performance. in this graph, the input impedance was swept with r s to preserve the match at each point. the noise figures for a source impedance of 50 are 7.1 db, 4.1 db, and 2.5 db for the resistive termination, active termination, and unterminated configurations, respectively. the noise figures for 200 are 4.6 db, 2.0 db, and 1.0 db, respectively. figure 45 shows the noise figure as it relates to r s for various values of r in , which is helpful for design purposes. input overdrive excellent overload behavior is of primary importance in ultra- sound. both the lna and vga have built-in overdrive protection and quickly recover after an overload event. input overload protection as with any amplifier, voltage clamping prior to the inputs is highly recommended if the application is subject to high transient voltages. a block diagram of a simplified ultrasound transducer interface is shown in figure 46 . a common transducer element serves the dual functions of transmitting and receiving ultrasound energy. during the transmitting phase, high voltage pulses are applied to the ceramic elements. a typical transmit/receive (t/r) switch can consist of four high voltage diodes in a bridge configuration. although the diodes ideally block transmit pulses from the sensitive receiver input, diode characteristics are not ideal, and resulting leakage transients imposed on the li-x inputs can be problematic. because ultrasound is a pulse system and time-of-flight is used to determine depth, quick recovery from input overloads is essential. overload can occur in the preamp and the vga. immediately following a transmit pulse, the typical vga gains are low, and the lna is subject to overload from t/r switch leakage. with increasing gain, the vga can become overloaded due to strong echoes that occur near field echoes and acoustically dense materials, such as bone. figure 46 illustrates an external overload protection scheme. a pair of back-to-back schottky diodes is installed prior to installing the ac-coupling capacitors. although the bas40 diodes are shown, any diode is prone to exhibiting some amount of shot noise. many types of diodes are available for achieving the desired noise per- formance. the configuration shown in figure 46 tends to add 2 nv/hz of input-referred noise. decreasing the 5 k resistor and increasing the 2 k resistor may improve noise contribution, depending on the application. with the diodes shown in figure 46 , clamping levels of 0.5 v or less significantly enhance the overload performance of the system. 0 6304-100 transducer 10nf 10nf 2k? 5k? 5k ? ad9271 tx driver hv bas40-04 +5 v ?5v lna figure 46. input overload protection
ad9271 cw doppler operation modern ultrasound machines used for medical applications employ a 2 n binary array of receivers for beam forming, with typical array sizes of 16 or 32 receiver channels phase-shifted and summed together to extract coherent information. when used in multiples, the desired signals from each channel can be summed to yield a larger signal (increased by a factor n, where n is the number of channels), and the noise is increased by the square root of the number of channels. this technique enhances the signal-to-noise performance of the machine. the critical elements in a beam-former design are the means to align the incoming signals in the time domain and the means to sum the individual signals into a composite whole. beam forming, as applied to medical ultrasound, is defined as the phase alignment and summation of signals that are generated from a common source but received at different times by a multielement ultrasound transducer. beam forming has two functions: it imparts directivity to the transducer, enhancing its gain, and it defines a focal point within the body from which the location of the returning echo is derived. the ad9271 includes the front-end components needed to implement analog beam forming for cw doppler operation. these components allow cw channels with similar phases to be coherently combined before phase alignment and down mixing, thus reducing the number of delay lines or adjustable phase shifters/ down mixers ( ad8333 or ad8339 ) required. next, if delay lines are used, the phase alignment is performed and then the channels are coherently summed and down converted by a dynamic range i/q demodulator. alternatively, if phase shifters/down mixers, such as the ad8333 and ad8339 , are used, phase alignment and downconversion are done before coherently summing all channels into i/q signals. in either case, the resultant i and q signals are filtered and sampled by two high resolution adcs, and the sampled signals are processed to extract the relevant doppler information. ad9271 g m g m g m g m lna rev. b | page 24 of 60 g m g m g m g m switch array lna 8 channel 16-bit adc q i lna lna ad9271 lna switch array 8 channel lna lna lna 2.5v ad8333 2.5v 2.5v 2.5v ad8333 16-bit adc 06304-096 600nh 600nh 600nh 600nh 600nh 700 ? 700 ? 700 ? 700 ? 600nh 600nh 600nh figure 47. typical cw doppler system using the ad9271 and ad8333 or ad8339
ad9271 rev. b | page 25 of 60 lna input-referred noise floor (5.4v rms) @ aaf bw = 15mhz lna + vga noise = 1.4nv/ hz crosspoint switch each lna is followed by a transconductance amp for v/i con- version. currents can be routed to one of six pairs of differential outputs or to 12 single-ended outputs for summing. each cwd output pin sinks 2.4 ma dc current, and the signal has a full-scale current of 2 ma for each channel selected by the crosspoint switch. for example, if four channels were to be summed on one cwd output, the output would sink 9.6 ma dc and have a full-scale current output of 8 ma. the maximum number of channels combined must be considered when setting the load impedance for i/v conversion to ensure that the full-scale swing and common-mode voltage are within the operating limits of the ad9271. when interfacing to the ad8339 , a common- mode voltage of 2.5 v and a full-scale swing of 2.8 v p-p are desired. this can be accomplish ed by connecting an inductor between each cwd output and a 2.5 v supply, and then connecting either a single-ended or differential load resistance to the cwd outputs. the value of resistance should be calculated based on the maximum number of channels that can be combined. cwd outputs are required under full-scale swing to be greater than 1.5 v and less than cwvdd (3.3 v supply). tgc operation the tgc signal path is fully differential throughout to maximize signal swing and reduce even-order distortion; however, the lnas are designed to be driven from a single-ended signal source. gain values are referenced from the single-ended lna input to the differential adc input. a simple exercise in understanding the maximum and minimum gain requirements is shown in figure 48 . lna fs (0.333v p-p se) adc fs (2 v p-p) ~5d b margin >8db margin adc noise floor (224v rms) minimum gain maximum gain 06304-097 lna adc 70db 87db vga gain range > 30db max channel gain > 40db figure 48. gain requirements of tgc for a 12-bit, 40 msps adc in summary, the maximum gain required is determined by ( adc noise floor / vga input noise floor ) + margin = 20 log(224/5.4) + 8 db = 40.3 db the minimum gain required is determined by ( adc input fs / vga input fs) + margin = 20 log(2/0.333) C 5 db = 10.6 db therefore, a 12-bit, 40 msps adc with 15 mhz of bandwidth should suffice in achieving the dynamic range required for most of todays ultrasound systems. the system gain is distributed as listed in table 8 . table 8. channel gain distribution section nominal gain (db) lna 14/15.6/18 attenuator 0 to ?30 vga amp 24 filter 0 adc 0 total 8.4 to 38.4/10 to 40/12.4 to 42.4 the linear-in-db gain (law conformance) range of the tgc path is 30 db, extending from 10 db to 40 db. the slope of the gain control interface is 31.6 db/v, and the gain control range is 0 v to 1 v as specified in equation 3. equation 4 is the expression for channel gain. 5.0)()()( +? ? + = (3) icpt v dbgain gain + = v db 6.31)( (4) where icpt is the intercept point of the tgc gain. in its default condition, the lna has a gain of 15.6 db (6) and the vga gain is ?6 db if the voltage on the gain pins is 0 v. this gives rise to a total gain (or icpt) of 10 db through the tgc path if the lna input is unmatched, or of 4 db if the lna is matched to 50 (r fb = 200 ). if the voltage on the gain pins is 1 v, however, the vga gain is 24 db. this gives rise to a total gain of 40 db through the tgc path if the lna input is unmatched, or of 34 db if the lna input is matched. each lna output is dc-coupled to a vga input. the vga consists of an attenuator with a range of 30 db followed by an amplifier with 24 db of gain for a net gain range of ?6 db to +24 db. the x-amp gain-interpolation technique results in low gain error and uniform bandwidth, and differential signal paths minimize distortion. at low gains, the vga should limit the system noise perfor- mance (snr); at high gains, the noise is defined by the source and lna. the maximum voltage swing is bound by the full-scale peak-to-peak adc input voltage (2 v p-p). both the lna and vga have limitations within each section of the tgc path, depending on the voltage applied to the gain+ and gain? pins. the lna has three limitations, or full-scale settings, depending on the gain selection applied through the spi interface. when a voltage of 0.2 v or less is applied to the gain pins, the lna operates near the full-scale input range to maximize the dynamic range of the adc without clipping the signal. when more than 0.2 v is applied to the gain pins, the input signal to the lna must be lowered to keep it within the full-scale range of the adc (see figure 49 ).
ad9271 rev. b | page 26 of 60 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 06304-1 v gain (v) 10 input full-scale (v p-p) 0 0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400 0.450 lna gain = 6x lna gain = 8x lna gain = 5x figure 49. lna/vga full-scale limitations variable gain amplifier the differential x-amp vga provides precise input attenuation and interpolation. it has a low input-referred noise of 4 nv/hz and excellent gain linearity. a simplified block diagram is shown in figure 50 . vip gain 3db vin g m 06304-078 postamp ? postamp + gain interpolator figure 50. simplified vga schematic the input of the vga is a 12-stage differential resistor ladder with 3.01 db per tap. the resulting total gain range is 30 db, which allows for range loss at the endpoints. the effective input resistance per side is 180 nominally for a total differential resistance of 360 . the ladder is driven by a fully differential input signal from the lna. lna outputs are dc-coupled to avoid external decoupling capacitors. the common-mode voltage of the attenuator and the vga is controlled by an amplifier that uses the same midsupply voltage derived in the lna, permitting dc coupling of the lna to the vga without introducing large offsets due to common- mode differences. however, any offset from the lna will be amplified as the gain is increased, producing an exponentially increasing vga output offset. the input stages of the x-amp are distributed along the ladder, and a biasing interpolator, controlled by the gain interface, determines the input tap point. with overlapping bias currents, signals from successive taps merge to provide a smooth attenuation range from 0 db to ?30 db. this circuit technique results in linear-in-db gain law conformance and low distortion levelsonly deviating 0.5 db or less from the ideal. the gain slope is monotonic with respect to the control voltage and is stable with variations in process, temperature, and supply. the x-amp inputs are part of a 24 db gain feedback amplifier that completes the vga. its bandwidth is about 70 mhz. the input stage is designed to reduce feedthrough to the output and to ensure excellent frequency response uniformity across the gain setting. gain control the gain control interface, gain, is a differential input. the vga gain, v gain , is shown in equation 3. v gain varies the gain of all vgas through the interpolator by selecting the appropriate input stages connected to the input attenuator. the nominal v gain range for 30 db/v is 0 v to 1 v, with the best gain linearity from about 0.1 v to 0.9 v, where the error is typically less than 0.5 db. for v gain voltages greater than 0.9 v and less than 0.1 v, the error increases. the value of v gain can exceed the supply voltage by 1 v without gain foldover. gain control response time is less than 750 ns to settle within 10% of the final value for a change from minimum to maximum gain. there are two ways in which the gain+ and gain? pins can be interfaced. using a single-ended method, a kelvin type of connection to ground can be used as shown in figure 51 . for driving multiple devices, it is preferable to use a differential method, as shown in figure 52 . in either method, the gain+ and gain? pins should be dc-coupled and driven to accom- modate a 1 v full-scale input. ad9271 gain+ gain? 100 ? 0 to 1v dc 50 ? 0.01f 0.01f 06304-109 kelvin connection figure 51. single-ended gain pins configuration gain? 50? gain+ ad9271 avdd 26k ? 10k ? 0.01f 0.25dc at 0.5v cm 0.25dc at 0.5v cm 100? 499 ? 0.5v dc 0.01f 100? 499? 523? 499 ? 0.5v cm ad8138 0 6304-098 figure 52. differential gain pins configuration vga noise in a typical application, a vga compresses a wide dynamic range input signal to within the input span of an adc. the input-referred noise of the lna limits the minimum resolvable input signal, whereas the output-referred noise, which depends primarily on the vga, limits the maximum instantaneous dynamic range that can be processed at any one particular gain control voltage. this latter limit is set in accordance with the total noise floor of the adc. output-referred noise as a function of v gain is shown in figure 24 and figure 25 for the short-circuit input conditions. the input
ad9271 rev. b | page 27 of 60 noise voltage is simply equal to the output noise divided by the measured gain at each point in the control range. the output-referred noise is a flat 63 nv/hz over most of the gain range, because it is dominated by the fixed output-referred noise of the vga. at the high end of the gain control range, the noise of the lna and source prevail. the input-referred noise reaches its minimum value near the maximum gain control voltage, where the input-referred contribution of the vga is miniscule. at lower gains, the input-referred noise and, therefore, the noise figure increases as the gain decreases. the instantaneous dynamic range of the system is not lost, however, because the input capacity increases as the input-referred noise increases. the contribution of the adc noise floor has the same dependence. the important relationship is the magnitude of the vga output noise floor relative to that of the adc. gain control noise is a concern in very low noise applications. thermal noise in the gain control interface can modulate the channel gain. the resultant noise is proportional to the output signal level and is usually evident only when a large signal is present. the gain interface includes an on-chip noise filter, which significantly reduces this effect at frequencies above 5 mhz. care should be taken to minimize noise impinging at the gain input. an external rc filter can be used to remove v gain source noise. the filter bandwidth should be sufficient to accommodate the desired control bandwidth. antialiasing filter the filter that the signal reaches prior to the adc is used to reject dc signals and to band limit the signal for antialiasing. figure 53 shows the architecture of the filter. 2k? 2k? 2k? 2k? 2k? 2k? 6.5c* 7.5c* 1c* *c = 0.5pf to 3.1pf 1c* 4k? 56pf/112pf 56pf/112pf 4k? 06304-099 figure 53. simplified filter schematic the filter can be configured for dc coupling or to have a single pole for high-pass filtering at either 700 khz or 350 khz (programmed through the spi). the high-pass pole, however, is not tuned and can vary by 30%. a third-order butterworth low-pass filter is used to reduce noise bandwidth and provide antialiasing for the adc. the filter uses on-chip tuning to trim the capacitors and in turn set the desired cutoff frequency and reduce variations. the default ?3 db cutoff is 1/3 the adc sample clock rate. the cutoff can be scaled to 0.7, 0.8, 0.9, 1, 1. 1, 1.2, or 1.3 times this frequency through the spi. the cutoff can be set from 8 mhz to 18 mhz. tuning is normally off to avoid changing the capacitor settings during critical times. the tuning circuit is enabled and disabled through the spi. initializing the tuning of the filter must be done after initial power-up and after reprogramming the filter cutoff scaling or adc sample rate. occasional retuning during an idle time is recommended to compensate for temperature drift. adc the ad9271 architecture consists of a pipelined adc divided into three sections: a 4-bit first stage followed by eight 1.5-bit stages and a 3-bit flash. each stage provides sufficient overlap to correct for flash errors in the preceding stages. the quantized outputs from each stage are combined into a 12-bit result in the digital correction logic. the pipelined architecture permits the first stage to operate on a new input sample and the remaining stages to operate on preceding samples. sampling occurs on the rising edge of the clock. each stage of the pipeline except for the last consists of a low resolution flash adc connected to a switched-capacitor dac and interstage residue amplifier (for example, a multiplying digital-to-analog converter (mdac)). the residue amplifier magnifies the difference between the reconstructed dac output and the flash input for the next stage in the pipeline. one bit of redundancy is used in each stage to facilitate digital correction of flash errors. the last stage consists of a flash adc. the output staging block aligns the data, carries out error cor- rection, and passes the data to the output buffers. the data is then serialized and aligned to the frame and output clock.
ad9271 rev. b | page 28 of 60 clock input considerations for optimum performance, the ad9271 sample clock inputs (clk+ and clk?) should be clocked with a differential signal. this signal is typically ac-coupled into the clk+ and clk? pins via a transformer or capacitors. these pins are biased internally and require no additional bias. figure 54 shows the preferred method for clocking the ad9271. a low jitter clock source, such as the valpey fisher oscillator vfac3-bhl-50mhz, is converted from single-ended to differential using an rf transfor mer. the back-to-back schottky diodes across the secondary transformer limit clock excursions into the ad9271 to approximately 0.8 v p-p differential. this helps prevent the large voltage swings of the clock from feeding through to other portions of the ad9271, and it preserves the fast rise and fall times of the signal, which are critical to low jitter performance. 0.1f 0.1f schottky diodes: hsm2812 0.1f 0.1f 3.3v 50? 100 ? clk? clk+ adc ad9271 mini-circuits adt1-1wt, 1:1z xfmr 06304-050 vfac3 out en figure 54. transformer-coupled differential clock if a low jitter clock is available, another option is to ac-couple a differential pecl signal to the sample clock input pins as shown in figure 55 . the ad951x family of clock drivers offers excellent jitter performance. 100 ? 0.1f 0.1f 0.1f 0.1f 240? 240? ad951x family 50? * clk clk * 50? resistor is optional. 06304-051 clk? clk+ adc ad9271 pecl driver 3.3v out vfac3 en 100 ? 0.1f 0.1f 0.1f 0.1f figure 55. differential pecl sample clock lvds driver clk clk * 50 ? resistor is optional. clk? clk+ adc ad9271 06304-052 ad951x family 3.3v out vfac3 en 50? * figure 56. differential lvds sample clock in some applications, it is acceptable to drive the sample clock inputs with a single-ended cmos signal. in such applications, clk+ should be driven directly from a cmos gate, and the clk? pin should be bypassed to ground with a 0.1 f capacitor in parallel with a 39 k resistor (see figure 57 ). although the clk+ input circuit supply is avdd (1.8 v), this input is designed to withstand input voltages of up to 3.3 v, making the selection of the drive logic voltage very flexible. 0.1f 0.1f 0.1f 39k? cmos driver 50 ? * optional 100 ? 0.1f clk clk * 50? resistor is optional. clk? clk+ adc ad9271 06304-053 ad951x family 3.3 v out vfac3 en figure 57. single-ended 1.8 v cmos sample clock 0.1f 0.1f 0.1f cmos driver 50? * optional 100 ? clk clk * 50? resistor is optional. 0.1f clk? clk+ adc ad9271 06304-054 ad951x family 3.3 v out vfac3 en figure 58. single-ended 3.3 v cmos sample clock clock duty cycle considerations typical high speed adcs use both clock edges to generate a variety of internal timing signals. as a result, these adcs may be sensitive to the clock duty cycle. commonly, a 5% tolerance is required on the clock duty cycle to maintain dynamic performance characteristics. the ad9271 contains a duty cycle stabilizer (dcs) that retimes the nonsampling edge, providing an internal clock signal with a nominal 50% duty cycle. this allows a wide range of clock input duty cycles without affecting the performance of the ad9271. when the dcs is on, noise and distortion perfor- mance are nearly flat for a wide range of duty cycles. however, some applications may require the dcs function to be off. if so, keep in mind that the dynamic range performance can be affected when operated in this mode. see the memory map section for more details on using this feature. the duty cycle stabilizer uses a delay-locked loop (dll) to create the nonsampling edge. as a result, any changes to the sampling frequency require approximately eight clock cycles to allow the dll to acquire and lock to the new rate. clock jitter considerations high speed, high resolution adcs are sensitive to the quality of the clock input. the degradation in snr at a given input frequency (f a ) due only to aperture jitter (t j ) can be calculated by snr degradation = 20 log 10[1/2 f a t j ]
ad9271 rev. b | page 29 of 60 in this equation, the rms aperture jitter represents the root mean square of all jitter sources, including the clock input, analog input signal, and adc aperture jitter. if undersampling applications are particularly sensitive to jitter (see figure 59 ). the clock input should be treated as an analog signal in cases where aperture jitter may affect the dynamic range of the ad9271. power supplies for clock drivers should be separated from the adc output driver supplies to avoid modulating the clock signal with digital noise. low jitter, crystal-controlled oscillators make the best clock sources, such as the valpey fisher vfac3 series. if the clock is generated from another type of source (by gating, dividing, or other methods), it should be retimed by the original clock during the last step. refer to the an-501 application note and the an-756 application note for more in-depth information about how jitter performance relates to adcs (visit www.analog.com ). 1 10 100 1000 16 bits 14 bits 12 bits 50 60 70 80 90 100 110 120 130 0.125ps 0.5ps 10 bits 8 bits 30 40 1.0ps 2.0ps analog input frequency (mhz) rms clock jitter requirement snr (db) 06304 -038 0.25ps figure 59. ideal snr vs. input frequency and jitter power dissipation and power-down mode as shown in figure 61 , the power dissipated by the ad9271 is proportional to its sample rate. the digital power dissipation does not vary much because it is determined primarily by the drvdd supply and bias current of the lvds output drivers ( figure 60 ). 800 32 current (ma) 0 0 06304-0 sampling frequency (msps) 700 600 500 400 300 200 100 10 20 30 40 50 i drvdd i avdd , 50msps speed grade i avdd , 40msps speed grade i avdd , 25msps speed grade figure 60. supply current vs. f sample for f in = 7.5 mhz 190 100 0 06304-031 sampling frequency (msps) power/channel (mw) 10 20 30 40 50 180 170 160 150 140 130 120 110 50msps speed grade 40msps speed grade 25msps speed grade figure 61. power per channel vs. f sample for f in = 7.5 mhz by asserting the pdwn pin high, the ad9271 is placed into power-down mode. in this state, the device typically dissipates 2 mw. during power-down, the lvds output drivers are placed into a high impedance state. the ad9271 returns to normal operating mode when the pdwn pin is pulled low. this pin is both 1.8 v and 3.3 v tolerant. by asserting the stby pin high, the ad9271 is placed into a standby mode. in this state, the device typically dissipates 65 mw. during standby, the entire part is powered down except the internal references. the lvds output drivers are placed into a high impedance state. this mode is well suited for applications that require power savings because it allows the device to be powered down when not in use and then quickly powered up. the time to power the device back up is also greatly reduced. the ad9271 returns to normal operating mode when the stby pin is pulled low. this pin is both 1.8 v and 3.3 v tolerant. in power-down mode, low power dissipation is achieved by shutting down the reference, reference buffer, pll, and biasing networks. the decoupling capacitors on reft and refb are discharged when entering power-down mode and must be recharged when returning to normal operation. as a result, the wake-up time is related to the time spent in the power-down mode: shorter cycles result in proportionally shorter wake-up times. to restore the device to full operation, approximately 1 ms is required when using the recommended 0.1 f and 4.7 f decoupling capacitors on the reft and refb pins and the 0.01 f decoupling capacitors on the gain pins. most of this time is dependent on the gain decoupling; higher value decoupling capacitors on the gain pins result in longer wake-up times. there are a number of other power-down options available when using the spi port interface. the user can individually power down each channel or put the entire device into standby mode. this allows the user to keep the internal pll powered up when fast wake-up times are required. the wake-up time is slightly dependent on gain. to achieve a 1 s wake-up time when the device is in standby mode, 0.5 v must be applied to the gain pins. see the memory map section for more details on using these features.
ad9271 rev. b | page 30 of 60 06304- ch1 500mv/div ? ch2 500mv/div ? ch3 500mv/div ? 5.0ns/div digital outputs and timing the ad9271 differential outputs conform to the ansi-644 lvds standard on default power-up. this can be changed to a low power, reduced signal option similar to the ieee 1596.3 standard by using the sdio pin or via the spi. this lvds standard can further reduce the overall power dissipation of the device by approximately 36 mw. see the sdio pin section or table 15 for more information. the lvds driver current is derived on chip and sets the output current at each output equal to a nominal 3.5 ma. a 100 differ- ential termination resistor placed at the lvds receiver inputs results in a nominal 350 mv swing at the receiver. the ad9271 lvds outputs facilitate interfacing with lvds receivers in custom asics and fpgas that have lvds capability for superior switching performance in noisy environments. single point-to-point net topologies are recommended with a 100 termination resistor placed as close to the receiver as possible. no far-end receiver termination and poor differential trace routing may result in timing errors. it is recommended that the trace length be no longer than 24 inches and that the differential output traces be kept close together and at equal lengths. an example of the fco, dco, and data stream with proper trace length and position can be found in figure 62 . 034 figure 62. lvds output timing example in ansi-644 mode (default) an example of the lvds output using the ansi-644 standard (default) data eye and a time interval error (tie) jitter histogram with trace lengths of less than 24 inches on regular fr-4 material is shown in figure 63 . figure 64 shows an example of the trace lengths exceeding 24 inches on regular fr-4 material. notice that the tie jitter histogram reflects the decrease of the data eye opening as the edge deviates from the ideal position; therefore, the user must determine if the waveforms meet the timing budget of the design when the trace lengths exceed 24 inches. additional spi options allow the user to further increase the internal termination (and therefore increase the current) of all eight outputs in order to drive longer trace lengths (see figure 65 ). even though this produces sharper rise and fall times on the data edges, is less prone to bit errors, and improves frequency distribution (see figure 65 ), the power dissipation of the drvdd supply increases when this option is used. in cases that require increased driver strength to the dco and fco outputs because of load mismatch, register 0x15 allows the user to double the drive strength. to do this, first set the appropriate bit in register 0x05. note that this feature cannot be used with bit 4 and bit 5 in register 0x15 because these bits take precedence over this feature. see the memory map section for more details. 06304-035 600 400 ?200 200 ?100 100 ?400 ?600 0 ?1.5ns ?0.5ns ?1.0ns 0ns 0.5ns 1.0ns 1.5ns eye diagram voltage (v) eye: all bits uls: 2398/2398 25 0 5 10 15 20 ?200ps ?100ps 0ps 100ps 200ps tie jitter histogram (hits) figure 63. data eye for lvds outputs in ansi-644 mode with trace lengths of less than 24 inches on standard fr-4
ad9271 rev. b | page 31 of 60 06304-036 400 ?300 300 ?200 200 ?100 100 ?400 0 ?1.5ns ?0.5ns ?1.0ns 0ns 0.5ns 1.0ns 1.5ns eye diagram voltage (v) eye: all bits uls: 2399/2399 25 5 10 15 20 06304-037 600 ?400 400 ?200 200 ?600 0 ?1.5ns ?0.5ns ?1.0ns 0ns 0.5ns 1.0ns 1.5ns eye diagram voltage (v) eye: all bits uls: 2396/2396 25 0 5 10 15 20 ?200ps ?100ps 0ps 100ps 200p tie jitter histogram (hits) 0 ?200ps ?100ps 0ps 100ps 200p tie jitter histogram (hits) s figure 64. data eye for lvds outputs in ansi-644 mode with trace lengths of greater than 24 inches on standard fr-4 s figure 65. data eye for lvds outputs in ansi-644 mode with 100 termination on and trace lengths of greater than 24 inches on standard fr-4
ad9271 rev. b | page 32 of 60 the format of the output data is offset binary by default. an example of the output coding format can be found in table 9 . to change the output data format to twos complement, see the memory map section. table 9. digital output coding code (vin+) ? (vin?), input span = 2 v p-p (v) digital output offset binary (d11 ... d0) 4095 +1.00 1111 1111 1111 2048 0.00 1000 0000 0000 2047 ?0.000488 0111 1111 1111 0 ?1.00 0000 0000 0000 data from each adc is serialized and provided on a separate channel. the data rate for each serial stream is equal to 12 bits times the sample clock rate, with a maximum of 600 mbps (12 bits 50 msps = 600 mbps). the lowest typical conversion rate is 10 msps, but the pll can be set up for encode rates as low as 5 msps via the spi if lower sample rates are required for a specific application. see the memory map section for details on enabling this feature. two output clocks are provided to assist in capturing data from the ad9271. dco is used to clock the output data and is equal to six times the sampling clock rate. data is clocked out of the ad9271 and must be captured on the rising and falling edges of the dco that supports double data rate (ddr) capturing. the frame clock output (fco) is used to signal the start of a new output byte and is equal to the sampling clock rate. see the timing diagram shown in figure 2 for more information. table 10. flexible output test modes output test mode bit sequence pattern name digital output word 1 digital output word 2 subject to data format select 0000 off (default) n/a n/a n/a 0001 midscale short 1000 0000 (8 bits) 10 0000 0000 (10 bits) 1000 0000 0000 (12 bits) 10 0000 0000 0000 (14 bits) same yes 0010 +full-scale short 1111 1111 (8 bits) 11 1111 1111 (10 bits) 1111 1111 1111 (12 bits) 11 1111 1111 1111 (14 bits) same yes 0011 ?full-scale short 0000 0000 (8 bits) 00 0000 0000 (10 bits) 0000 0000 0000 (12 bits) 00 0000 0000 0000 (14 bits) same yes 0100 checkerboard 1010 1010 (8 bits) 10 1010 1010 (10 bits) 1010 1010 1010 (12 bits) 10 1010 1010 1010 (14 bits) 0101 0101 (8 bits) 01 0101 0101 (10 bits) 0101 0101 0101 (12 bits) 01 0101 0101 0101 (14 bits) no 0101 pn sequence long 1 n/a n/a yes 0110 pn sequence short 1 n/a n/a yes 0111 one-/zero-word toggle 1111 1111 (8 bits) 11 1111 1111 (10 bits) 1111 1111 1111 (12 bits) 11 1111 1111 1111 (14 bits) 0000 0000 (8 bits) 00 0000 0000 (10 bits) 0000 0000 0000 (12 bits) 00 0000 0000 0000 (14 bits) no 1000 user input register 0x19 and register 0x 1a register 0x1b and register 0x1c no 1001 1-/0-bit toggle 1010 1010 (8 bits) 10 1010 1010 (10 bits) 1010 1010 1010 (12 bits) 10 1010 1010 1010 (14 bits) n/a no 1010 1 sync 0000 1111 (8 bits) 00 0001 1111 (10 bits) 0000 0011 1111 (12 bits) 00 0000 0111 1111 (14 bits) n/a no 1011 one bit high 1000 0000 (8 bits) 10 0000 0000 (10 bits) 1000 0000 0000 (12 bits) 10 0000 0000 0000 (14 bits) n/a no 1100 mixed bit frequency 1010 0011 (8 bits) 10 0110 0011 (10 bits) 1010 0011 0011 (12 bits) 10 1000 0110 0111 (14 bits) n/a no 1 all test mode options except pn sequence short and pn sequence long can support 8- to 14-bit word lengths in order to verify d ata capture to the receiver.
ad9271 rev. b | page 33 of 60 when using the serial port interface (spi), the dco phase can be adjusted in 60 increments relative to the data edge. this enables the user to refine system timing margins if required. the default dco timing, as shown in figure 2 , is 90 relative to the output data edge. an 8-, 10-, and 14-bit serial stream can also be initiated from the spi. this allows the user to implement different serial streams to test the devices compatibility with lower and higher resolution systems. when changing the resolution to an 8- or 10-bit serial stream, the data stream is shortened. when using the 14-bit option, the data stream stuffs two 0s at the end of the normal 14-bit serial data. when using the spi, all of the da ta outputs can also be inverted from their nominal state. this is not to be confused with inverting the serial stream to an lsb-first mode. in default mode, as shown in figure 2 , the msb is represented first in the data output serial stream. however, this can be inverted so that the lsb is repre- sented first in the data output serial stream (see figure 3 ). there are 12 digital output test pattern options available that can be initiated through the spi. this feature is useful when validating receiver capture and timing. refer to table 10 for the output bit sequencing options available. some test patterns have two serial sequential words and can be alternated in various ways, depending on the test pattern chosen. it should be noted that some patterns may not adhere to the data format select option. in addition, customer user patterns can be assigned in the 0x19, 0x1a, 0x1b, and 0x1c register addresses. all test mode options except pn sequence short and pn sequence long can support 8- to 14-bit word lengths in order to verify data capture to the receiver. the pn sequence short pattern produces a pseudorandom bit sequence that repeats itself every 2 9 ? 1 bits, or 511 bits. a description of the pn sequence and how it is generated can be found in section 5.1 of the itu-t 0.150 (05/96) standard. the only difference is that the starting value is a specific value instead of all 1s (see table 11 for the initial values). the pn sequence long pattern produces a pseudorandom bit sequence that repeats itself every 2 23 ? 1 bits, or 8,388,607 bits. a description of the pn sequence and how it is generated can be found in section 5.6 of the itu-t 0.150 (05/96) standard. the only differences are that the starting value is a specific value instead of all 1s and the ad9271 inverts the bit stream with relation to the itu standard (see table 11 for the initial values). table 11. pn sequence sequence initial value first three output samples (msb first) pn sequence short 0x0df 0xdf9, 0x353, 0x301 pn sequence long 0x29b80a 0x591, 0xfd7, 0xa3 consult the memory map section for information on how to change these additional digital output timing features through the spi. sdio pin this pin is required to operate the spi. it has an internal 30 k pull-down resistor that pulls this pin low and is only 1.8 v tolerant. if applications require that this pin be driven from a 3.3 v logic level, insert a 1 k resistor in series with this pin to limit the current. sclk pin this pin is required to operate the spi port interface. it has an internal 30 k pull-down resistor that pulls this pin low and is both 1.8 v and 3.3 v tolerant. csb pin this pin is required to operate the spi port interface. it has an internal 70 k pull-down resistor that pulls this pin low and is both 1.8 v and 3.3 v tolerant. rbias pin to set the internal core bias current of the adc, place a resistor that is nominally equal to 10.0 k between the rbias pin and ground. using a resistor of another value degrades the performance of the device. therefore, it is imperative that at least a 1% tolerance on this resistor be used to achieve consistent performance. voltage reference a stable and accurate 0.5 v voltage reference is built into the ad9271. this is gained up internally by a factor of 2, setting vref to 1.0 v, which results in a full-scale differential input span of 2.0 v p-p for the adc. vref is set internally by default, but the vref pin can be driven externally with a 1.0 v reference to achieve more accuracy. however, full-scale ranges below 2.0 v p-p are not supported by this device. when applying the decoupling capacitors to the vref, reft, and refb pins, use ceramic low esr capacitors. these capacitors should be close to reference pins and on the same layer of the pcb as the ad9271. the recommended capacitor values and configurations for the ad9271 reference pin can be found in figure 66 . table 12. reference settings selected mode sense voltage resulting vref (v) resulting differential span (v p-p) external reference avdd n/a 2 external reference internal, 2 v p-p fsr agnd to 0.2 v 1.0 2.0
ad9271 rev. b | page 34 of 60 external reference operation internal reference operation the use of an external reference may be necessary to enhance the gain accuracy of the adc or to improve thermal drift charac- teristics. figure 69 shows the typical drift characteristics of the internal reference in 1 v mode. a comparator within the ad9271 detects the potential at the sense pin and configures the reference. if sense is grounded, the reference amplifier switch is connected to the internal resistor divider (see figure 66 ), setting vref to 1 v. when the sense pin is tied to avdd, the internal reference is disabled, allowing the use of an external reference. the external reference is loaded with an equivalent 6 k load. an internal reference buffer generates the positive and negative full-scale references, reft and refb, for the adc core. therefore, the external reference must be limited to a nominal voltage of 1.0 v. the reft and refb pins establish their input span of the adc core from the reference configuration. the analog input full- scale range of the adc equals twice the voltage at the reference pin for either an internal or an external reference configuration. 1f 0.1f vref sense 0.5v reft 0.1f 0.1f 4.7f 0.1f refb select logic adc core + vin? vin+ 4 06304-06 6304-065 . 5 5 0 ?5 ?10 ?15 ?20 ?25 03 3.0 2.5 2.0 1.5 1.0 0.5 06304-017 vref error (%) current load (ma) figure 66. internal reference configuration figure 68. vref accuracy vs. load, ad9271-50 0.02 0 ?0.02 ?0.04 ?0.06 ?0.08 ?0.10 ?0.12 ?0.14 ?0.16 ?0.18 ?0.20 ?40 80 60 40 20 0 ?20 06304-015 vref error (%) temperature (c) vin? vin+ 1f* 0.1f* vref sense avdd 0.5v reft 0.1f 0.1f 4.7f 0.1f refb select logic adc core + external reference *optional. figure 69. typical vref drift, ad9271-50 0 figure 67. external reference operation
ad9271 rev. b | page 35 of 60 serial port interface (spi) the ad9271 serial port interface allows the user to configure the signal chain for specific functions or operations through a structured register space provided inside the chip. this offers the user added flexibility and customization depending on the application. addresses are accessed via the serial port and can be written to or read from via the port. memory is organized into bytes that can be further divided into fields, as documented in the memory map section. detailed operational information can be found in the analog devices, inc., an-877 application note, interfacing to high speed adcs via spi . three pins define the serial port interface, or spi: the sclk, sdio, and csb pins. the sclk (serial clock) is used to synchronize the read and write data presented to the device. the sdio (serial data input/output) is a dual-purpose pin that allows data to be sent to and read from the devices internal memory map registers. the csb (chip select bar) is an active low control that enables or disables the read and write cycles (see table 13 ). table 13. serial port pins pin function sclk serial clock. the serial shift clock input. sclk is used to synchronize serial interface reads and writes. sdio serial data input/output. a dual-purpose pin. the typical role for this pin is as an input or output, depending on the instruction sent and the relative position in the timing frame. csb chip select bar (active low). this control gates the read and write cycles. the falling edge of the csb in conjunction with the rising edge of the sclk determines the start of the framing sequence. during an instruction phase, a 16-bit instruction is transmitted, followed by one or more data bytes, which is determined by bit field w0 and bit field w1. an example of the serial timing and its definitions can be found in figure 71 and table 14 . in normal operation, csb is used to signal to the device that spi commands are to be received and processed. when csb is brought low, the device processes sclk and sdio to process instructions. normally, csb remains low unti l the communication cycle is complete. however, if connected to a slow device, csb can be brought high between bytes, al lowing older microcontrollers enough time to transfer data into shift registers. csb can be stalled when transferring one, two, or three bytes of data. when w0 and w1 are set to 11, the device enters streaming mode and continues to process data, either reading or writing, until the csb is taken high to end the communication cycle. this allows complete memory transfers without having to provide additional instruct- tions. regardless of the mode, if csb is taken high in the middle of any byte transfer, the spi state machine is reset and the device waits for a new instruction. in addition to the operation mode s, the spi port can be configured to operate in different manners. for example, csb can be tied low to enable 2-wire mode. when csb is tied low, sclk and sdio are the only pins required for communication. although the device is synchronized duri ng power-up, caution must be exercised when using this mode to ensure that the serial port remains synchronized with the csb line. when operating in 2-wire mode, it is recommended th at a 1-, 2-, or 3-byte transfer be used exclusively. without an active csb line, streaming mode can be entered but not exited. in addition to word length, the instruction phase determines if the serial frame is a read or write operation, allowing the serial port to be used to both progra m the chip and read the contents of the on-chip memory. if the instruction is a readback operation, performing a readback causes the serial data input/output (sdio) pin to change direction from an input to an output at the appropriate point in the serial frame. data can be sent in msb- or lsb-first mode. msb-first mode is the default at power-up and can be changed by adjusting the configuration register. for more information about this and other features, see the an-877 application note, interfacing to high speed adcs via spi . hardware interface the pins described in table 13 constitute the physical interface between the users programming device and the serial port of the ad9271. the sclk and csb pins function as inputs when using the spi interface. the sdio pin is bidirectional, functioning as an input during write phases and as an output during readback. in cases where multiple sdio pins share a common connection, care should be taken to ensure that proper v oh levels are met. figure 70 shows the number of sdio pins that can be connected together, assuming the same load as the ad9271 and the resulting v oh level. 06304-113 number of sdio pins connected together v oh (v) 1.715 1.720 1.725 1.730 1.735 1.740 1.745 1.750 1.755 1.760 1.765 1.770 1.775 1.780 1.785 1.790 1.795 1.800 03 0 20 10 40 50 60 70 80 90 100 figure 70. sdio pin loading
ad9271 rev. b | page 36 of 60 this interface is flexible enough to be controlled by either serial proms or pic mirocontrollers. this provides the user an alternative method, other than a full spi controller, to program the device (see the an-812 application note). don?t care don?t care don?t care don?t care sdio sclk csb t s t dh t hi t clk t lo t ds t h r/w w1 w0 a12 a11 a10 a9 a8 a7 d5 d4 d3 d2 d1 d0 06304-068 figure 71. serial timing details table 14. serial timing definitions parameter minimum timing (ns) description t ds 5 setup time between the data and the rising edge of sclk t dh 2 hold time between the data and the rising edge of sclk t clk 40 period of the clock t s 5 setup time between csb and sclk t h 2 hold time between csb and sclk t hi 16 minimum period that sclk should be in a logic high state t lo 16 minimum period that sclk should be in a logic low state t en_sdio 10 minimum time for the sdio pin to switch from an input to an output relative to the sclk falling edge (not shown in figure 71 ) t dis_sdio 10 minimum time for the sdio pin to switch from an output to an input relative to the sclk rising edge (not shown in figure 71 )
ad9271 rev. b | page 37 of 60 memory map reading the memory map table each row in the memory map table has eight address locations. the memory map is roughly divided into three sections: the chip configuration register map (address 0x00 to address 0x02), the device index and transfer register map (address 0x04, address 0x05, and address 0xff), and the adc functions register map (address 0x08 to address 0x2d). the leftmost column of the memory map indicates the register address number; the default value is shown in the second rightmost column. the bit 7 (msb) column is the start of the default hexadecimal value given. for example, address 0x09, the clock register, has a default value of 0x01, meaning that bit 7 = 0, bit 6 = 0, bit 5 = 0, bit 4 = 0, bit 3 = 0, bit 2 = 0, bit 1 = 0, and bit 0 = 1, or 0000 0001 in binary. this setting is the default for the duty cycle stabilizer in the on condition. by writing 0 to bit 0 of this address followed by writing 0x01 in register 0xff (transfer bit), the duty cycle stabilizer turns off. it is important to follow each writing sequence with a transfer bit to update the spi registers. all registers, except register 0x00, register 0x02, register 0x04, register 0x05, and register 0xff, are buffered with a master-slave latch and require writing to the transfer bit. for more information on this and other functions, consult the an- 877 application note, interfacing to high speed adcs via spi . reserved locations undefined memory locations should not be written to except when writing the default values suggested in this data sheet. addresses that have values marked as 0 should be considered reserved and have 0 written into their registers during power-up. default values after a reset, critical registers are automatically loaded with default values. these values are indicated in table 15 , where an x refers to an undefined feature. logic levels an explanation of various registers follows: bit is set is synonymous with bit is set to logic 1 or writing logic 1 for the bit. similarly, clear a bit is synonymous with bit is set to logic 0 or writing logic 0 for the bit.
ad9271 rev. b | page 38 of 60 table 15. memory map register 1 addr. (hex) register name bit 7 (msb) bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 (lsb) default value notes/ comments chip configuration registers 00 chip_port_config 0 lsb first 1 = on 0 = off (default) soft reset 1 = on 0 = off (default) 1 1 soft reset 1 = on 0 = off (default) lsb first 1 = on 0 = off (default) 0 0x18 the nibbles should be mirrored so that lsb- or msb-first mode is set correctly regardless of shift mode. 01 chip_id chip id bits [7:0] (ad9271 = 0x13), (default) read only default is unique chip id, different for each device. this is a read- only register. 02 chip_grade x x child id [5:4] (identify device variants of chip id) 00 = 50 msps (default) 01 = 40 msps 10 = 25 msps x x x x 0x00 child id used to differentiate graded devices. device index and transfer registers 04 device_index_2 x x x x data channel h 1 = on (default) 0 = off data channel g 1 = on (default) 0 = off data channel f 1 = on (default) 0 = off data channel e 1 = on (default) 0 = off 0x0f bits are set to determine which on-chip device receives the next write command. 05 device_index_1 x x clock channel dco 1 = on 0 = off (default) clock channel fco 1 = on 0 = off (default) data channel d 1 = on (default) 0 = off data channel c 1 = on (default) 0 = off data channel b 1 = on (default) 0 = off data channel a 1 = on (default) 0 = off 0x0f bits are set to determine which on-chip device receives the next write command. ff device_update x x x x x x x sw transfer 1 = on 0 = off (default) 0x00 synchronously transfers data from the master shift register to the slave. adc functions registers 08 modes x x x x lna bypass 1 = on 0 = off (default) internal power-down mode 000 = chip run (default) 001 = full power-down 010 = standby 011 = reset 100 = cw mode (tgc pdwn) 0x00 determines various generic modes of chip operation. 09 clock x x x x x x x duty cycle stabilizer 1 = on (default) 0 = off 0x01 turns the internal duty cycle stabilizer on and off.
ad9271 rev. b | page 39 of 60 addr. (hex) register name bit 7 (msb) bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 (lsb) default value notes/ comments 0d test_io user test mode 00 = off (default) 01 = on, single alternate 10 = on, single once 11 = on, alternate once reset pn long gen 1 = on 0 = off (default) reset pn short gen 1 = on 0 = off (default) output test modesee table 10 0000 = off (default) 0001 = midscale short 0010 = +fs short 0011 = ?fs short 0100 = checkerboard output 0101 = pn sequence long 0110 = pn sequence short 0111 = one-/zero-word toggle 1000 = user input 1001 = 1-/0-bit toggle 1010 = 1 sync 1011 = one bit high 1100 = mixed bit frequency (format determined by output_mode) 0x00 when this register is set, the test data is placed on the output pins in place of normal data. (local, expect for pn sequence.) 0f flex_channel_input filter cutoff frequency control 0000 = 1.3 1/3 f sample 0001 = 1.2 1/3 f sample 0010 = 1.1 1/3 f sample 0011 = 1.0 1/3 f sample 0100 = 0.9 1/3 f sample 0101 = 0.8 1/3 f sample 0110 = 0.7 1/3 f sample x x x x 0x30 antialiasing filter cutoff (global). 10 flex_offset x x 6-bit lna offset adjustment 011001 = 50 msps speed grade 011010 = 40 msps speed grade 011111 = 25 msps speed grade 0x20 lna force offset correction (local). 11 flex_gain x x x x x x lna gain 00 = 5 01 = 6 10 = 8 0x01 lna gain adjustment (global). 14 output_mode x 0 = lvds ansi-644 (default) 1 = lvds low power, (ieee 1596.3 similar) x x x output invert 1 = on 0 = off (default) 00 = offset binary (default) 01 = twos complement 0x00 configures the outputs and the format of the data. 15 output_adjust x x output driver termination 00 = none (default) 01 = 200 10 = 100 11 = 100 x x x dco and fco 2 drive strength 1 = on 0 = off (default) 0x00 determines lvds or other output prop erties. primarily functions to set the lvds span and common- mode levels in place of an external resistor. 16 output_phase x x x x 0011 = output clock phase adjust (0000 through 1010) (default: 180 relative to data edge) 0000 = 0 relative to data edge 0001 = 60 relative to data edge 0010 = 120 relative to data edge 0011 = 180 relative to data edge 0100 = 240 relative to data edge 0101 = 300 relative to data edge 0110 = 360 relative to data edge 0111 = 420 relative to data edge 1000 = 480 relative to data edge 1001 = 540 relative to data edge 1010 = 600 relative to data edge 1011 to 1111 = 660 relative to data edge 0x03 on devices that utilize global clock divide, determines which phase of the divider output is used to supply the output clock. internal latching is unaffected.
ad9271 rev. b | page 40 of 60 addr. (hex) register name bit 7 (msb) bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 (lsb) default value notes/ comments 19 user_patt1_lsb b7 b6 b5 b4 b3 b2 b1 b0 0x00 user-defined pattern, 1 lsb (global). 1a user_patt1_msb b15 b14 b13 b12 b11 b10 b9 b8 0x00 user-defined pattern, 1 msb (global). 1b user_patt2_lsb b7 b6 b5 b4 b3 b2 b1 b0 0x00 user-defined pattern, 2 lsb (global). 1c user_patt2_msb b15 b14 b13 b12 b11 b10 b9 b8 0x00 user-defined pattern, 2 msb (global). 21 serial_contr ol lsb first 1 = on 0 = off (default) x x x <10 msps, low encode rate mode 1 = on 0 = off (default) 000 = 12 bits (default, normal bit stream) 001 = 8 bits 010 = 10 bits 011 = 12 bits 100 = 14 bits 0x00 serial stream control. default causes msb first and the native bit stream (global). 22 serial_ch_stat x x x x x x channel output reset 1 = on 0 = off (default) channel power- down 1 = on 0 = off (default) 0x00 used to power down individ ual sections of a converter (local). 2b flex_filter x enable automatic low-pass tuning 1 = on 0 = off (default) x x x x high-pass filter cutoff 00 = dc (default) 01 = 700 khz 10 = 350 khz 0x00 filter cutoff (global). 2c analog_input x x x x x x x losw-x 1 = on 0 = off (default) 0x00 lna active termination/ input impedance (global). 2d cross_point_switch x x x crosspoint switch enable 0 0000 = cwd0 (differential) 0 0001 = cwd1 (differential) 0 0010 = cwd2 (differential) 0 0011 = cwd3 (differential) 0 0100 = cwd4 (differential) 0 0101 = cwd5 (differential) 0 0111 = power down cw channel 1 0000 = cwd0+ (single ended) 1 0001 = cwd1+ (single ended) 1 0010 = cwd2+ (single ended) 1 0011 = cwd3+ (single ended) 1 0100 = cwd4+ (single ended) 1 0101 = cwd5+ (single ended) 1 0111 = power down cw channel 1 1000 = cwd0? (single ended) 1 1001 = cwd1? (single ended) 1 1010 = cwd2? (single ended) 1 1011 = cwd3? (single ended) 1 1100 = cwd4? (single ended) 1 1101 = cwd5? (single ended) 1 1111 = power down cw channel 0x07 crosspoint switch enable (local). 1 x = an undefined feature
ad9271 rev. b | page 41 of 60 applications information design guidelines before starting design and layout of the ad9271 as a system, it is recommended that the designer become familiar with these guidelines, which discuss the special circuit connections and layout requirements needed for certain pins. power and ground recommendations when connecting power to the ad9271, it is recommended that two separate 1.8 v supplies be used: one for analog (avdd) and one for digital (drvdd). the ad9271 also requires a 3.3 v supply (cwvdd) for the crosspoint section. if only one 1.8 v supply is available, it should be routed to the avdd first and then tapped off and isolated with a ferrite bead or a filter choke preceded by decoupling capacitors for the drvdd. the user should employ several decoupling capacitors on all supplies to cover both high and low frequencies. these capacitors should be located close to the point of entry at the pc board level and close to the parts with minimal trace lengths. a single pc board ground plane should be sufficient when using the ad9271. with proper decoupling and smart parti- tioning of the pc boards analog, digital, and clock sections, optimum performance can be easily achieved. exposed paddle thermal heat slug recommendations it is required that the exposed paddle on the underside of the device be connected to the analog ground (agnd) to achieve the best electrical and thermal performance of the ad9271. an exposed continuous copper plane on the pcb should mate to the ad9271 exposed paddle, pin 0. the copper plane should have several vias to achieve the lowest possible resistive thermal path for heat dissipation to flow through the bottom of the pcb. these vias should be filled or plugged with nonconductive epoxy. to maximize the coverage and adhesion between the device and pcb, partition the continuous copper pad by overlaying a silk- screen or solder mask to divide it into several uniform sections. this ensures several tie points between the two during the reflow process. using one continuous plane with no partitions guarantees only one tie point between the ad9271 and pcb. see figure 72 for a pcb layout example. for more detailed information on packaging and for more pcb layout examples, see the an-772 application note. silkscreen p a rtition pin 1 i ndicator 06304-069 figure 72. typical pcb layout
ad9271 rev. b | page 42 of 60 evaluation board the ad9271 evaluation board provides all the support circuitry required to operate the ad9271 in its various modes and con- figurations. the lna is driven differentially through a transformer. figure 73 shows the typical bench characterization setup used to evaluate the ac performance of the ad9271. it is critical that the signal sources used for the analog input and clock have very low phase noise (<1 ps rms jitter) to realize the optimum performance of the signal chain. proper filtering of the analog input signal to remove harmonics and lower the integrated or broadband noise at the input is also necessary to achieve the specified noise performance. see the quick start procedure section to get started and figure 75 to figure 86 for the complete schematics and layout diagrams that demonstrate the routing and grounding techniques that should be applied at the system level. power supplies this evaluation board comes wi th a wall-mountable switching power supply that provides a 6 v, 2 a maximum output. connect the supply to the rated 100 v ac to 240 v ac wall outlet at 47 hz to 63 hz. the other end is a 2.1 mm inner diameter jack that connects to the pcb at p701. once on the pc board, the 6 v supply is fused and conditioned before connecting to three low dropout linear regulators that supply the proper bias to each of the various sections on the board. when operating the evaluation board in a nondefault condition, l702 to l704 can be removed to disconnect the switching power supply. this enables the user to bias each section of the board individually. use p501 to connect a different supply for each section. at least one 1.8 v supply is needed with a 1 a current capability for avdd_dut and drvdd_dut; however, it is recommended that separate supplies be used for both analog and digital domains. to operate the evaluation board using the spi and alternate clock options, a separate 3.3 v analog supply is needed in addition to the other supplies. the 3.3 v supply, or avdd_3.3 v, should have a 1 a current capability. to bias the crosspoint switch circuitry or cw section, separate +5 v and ?5 v supplies are required at p511. these should each have 1 a current capability. this section cannot be biased from a 6 v, 2 a wall supply. separate supplies are required at p511. input signals when connecting the clock and analog source, use clean signal generators with low phase noise, such as rohde & schwarz sma or hp8644b signal generators or the equivalent. use a 1 m, shielded, rg-58, 50 coaxial cable for making connections to the evalu- ation board. enter the desired frequency and amplitude from the specifications tables. the evaluation board is set up to be clocked from the crystal oscillator, osc401. if a different or external clock source is desired, follow the instructions for clock outlined in the default operation and jumper selection settings section. typically, most analog devices evaluation boards can accept ~2.8 v p-p or 13 dbm sine wave input for the clock. when connecting the analog input source, it is recommended to use a multipole, narrow-band, band-pass filter with 50 terminations. analog devices uses tte and k&l microwave, inc., band-pass filters. the filter should be connected directly to the evaluation board. output signals the default setup uses the fifo5 high speed, dual-channel fifo data capture board (hsc-adc-evalcz). two of the eight channels can then be evaluated at the same time. for more information on channel settings on these boards and their optional settings, visit www.analog.com/fifo . rohde & schwarz, sma, 2v p-p signal synthesizer rohde & schwarz, fs5a20 spectrum analyzer band-pass filter ch a to ch h 12-bit serial lvds ad9271 hsc-adc-evalcz fifo data capture board fpga pc running adc analyzer or visual analog user software 1.8v ?+ ?+ avdd_dut vreg drvdd_dut gnd avdd_3.3v gnd gnd 1.8v 6v dc 2a max vfac3 oscillator wall outlet 100v to 240v ac 47hz to 63hz switching power supply ?+ gnd 3.3v ?+ ps spi spi 06304-070 analog input cw output clk evaluation board usb connector (data/spi) figure 73. evaluation board connection
ad9271 rev. b | page 43 of 60 default operation and jumper selection settings the following is a list of the default and optional settings or modes allowed on the ad9271 rev. b evaluation board. ? power: connect the switching power supply that is supplied in the evaluation kit between a rated 100 v ac to 240 v ac wall outlet at 47 hz to 63 hz and p701. ? ain: the evaluation board is set up for a transformer- coupled analog input with an optimum 50 impedance match of 18 mhz of bandwidth. for a different bandwidth response, use the antialiasing filter settings. ? vref: vref is set to 1.0 v by tying the sense pin to ground, r317. this causes the adc to operate in 2.0 v p-p full-scale range. a separate external reference option using the adr510 or adr520 is also included on the evaluation board. populate r311 and r315 with 0 resistors and remove c307. proper use of the vref options is noted in the volt age refe rence section. note that adc full-scale ranges less than 2.0 v p-p are not supported by this device. ? rbias: rbias has a default setting of 10 k (r301) to ground and is used to set the adc core bias current. however, note that using other than a 10 k resistor for rbias may degrade the performance of the device, depending on the resistor chosen. ? clock: the default clock input circuitry is derived from a simple transformer-coupled circuit using a high bandwidth 1:1 impedance ratio transformer (t401) that adds a very low amount of jitter to the clock path. the clock input is 50 terminated and ac-coupled to handle single-ended sine wave types of inputs. the transformer converts the single-ended input to a differential signal that is clipped before entering the adc clock inputs. the evaluation board is already set up to be clocked from the crystal oscillator, osc401. this oscillator is a low phase noise oscillator from valpey fisher (vfac3-bhl-50mhz). if a different clock source is desired, remove r403, set jumper j401 to disable the oscillator from running, and connect the external clock source to the sma connector, p401. a differential lvpecl clock driver can also be used to clock the adc input using the ad9515 (u401). populate r406 and r407 with 0 resistors and remove r415 and r416 to disconnect the default clock path inputs. in addition, populate c405 and c406 with a 0.1 f capacitor and remove c409 and c410 to disconnect the default clock path outputs. the ad9515 has many pin-strappable options that are set to a default mode of operation. consult the ad9515 data sheet for more information about these and other options. ? pdwn: to enable the power-down feature, short p303 to the on position (avdd) on the pdwn pin. ? stby: to enable the standby feature, short p302 to the on position (avdd) on the stby pin. ? gain+, gain?: to change the vga attenuation, drive the gain+ pin from 0 v to 1 v on j301. this changes the vga gain from 0 db to 30 db. this feature can also be driven from the r335 and r336 on-board resistive divider by installing a 0 resistor in r337. ? non-spi mode: for users who wish to operate the dut without using the spi, remove the jumpers on j501. this disconnects the csb, sclk, and sdio pins from the control bus, allowing the dut to operate in its simplest mode. each of these pins has internal termination and will float to its respective level. note that the device will only work in its default condition. ? cwd+, cwd?: to view the cwd2+/cwd2? and cwd3+/ cwd3? outputs, jumper together the appropriate outputs on p403. all outputs are summed together on iop and ion buses, fed to a 1:4 impedance ratio transformer, and buffered so that the user can view the output on a spectrum analyzer. this can be configured to be viewed in single- ended mode (default) or in differential mode. to set the voltage for the appropriate number of channels to be summed, change the value of r447 and r448 on the primary transformer (t402). upon shipment, the cwd0+/cwd0?, cwd1+/cwd1?, cwd4+/cwd4?, and cwd5+/cwd5? outputs are properly biased and ready to use with the ad8339 quad i/q demodulator and phase shifter. the ad9271 evaluation board simply snaps into place on the ad8339 evaluation board (ad8339-evalz). remove the jumpers connected to p3a and p4a on the ad8339 evaluation board, and snap the standoffs labeled mh502, mh504, and mh505 that are provided with the ad9271 into the ad8339 evaluation board standoff holes in the center of the board. the standoffs automatically lock into place and create a direct connection between the ad9271 cwdx outputs and the ad8339 inputs. ? doutx+, doutx?: if an alternative data capture method to the setup described in figure 80 is used, optional receiver terminations, r601 to r610, can be installed next to the high speed backplane connector.
ad9271 rev. b | page 44 of 60 4. in spi controller, select controller dialog from the config menu. in the program control box, ensure that enable auto channel update is selected and click ok . quick start procedure the following is a list of the default and optional settings when using the ad9271 either on the evaluation board or at the system level design. 5. in the global tab of spi controller, find the device index(4/5) box. in the adc column, click s so that the adjustment in the next step applies to all channels. if an evaluation board is not being used, follow only the spi controller steps. 6. in the adc a tab of spi controller, find the offset(10) box and use the drop-down menu labeled offset adj to select the correct lna offset correction: 25 decimal for the 50 msps speed grade, 26 decimal for the 40 msps speed grade, or 31 decimal for the 25 msps speed grade. when using the ad9271 evaluation board, 1. open adc analyzer on a pc, click configuration , and select the appropriate product configuration file. if the correct product configuration file is not available, choose a similar product configuration file or click cancel and create a new one. see the adc analyzer user manual located at www.analog.com/fifo . 7. click fft ( ) in visual analog. 0 ?130 02 06304-119 frequency (mhz) amplitude (dbfs) 5 ?10 ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ?100 ?110 ?120 51 01 52 0 f in = 3.5mhz @ ?1dbfs lna = 6 v gain = 1v filter tuned hpf = 700khz 2. from the config menu, choose channel select . to evaluate channel a on the adc evaluation board, ensure that only the channel b checkbox in adc analyzer is selected. channel a through channel d co rrespond to channel b in adc analyzer. channel e through channel h co rrespond to channel a in adc analyzer. 3. click spi in adc analyzer to open the spi controller software. if prompted for a configuration file, select the appropriate one. if not, look at the title bar of the window to see which configuration is loaded. if necessary, choose cfg open from the file menu and select the appropriate one. note that the chip id(1) field may be filled in regardless of whether the correct spi controller configuration file is loaded. figure 74. typical fft, ad9271-50 8. adjust the amplitude of the input signal so that the fundamental is at the desired level. (examine the fund: reading in the left panel of the adc analyzer fft window.) if the gain pins voltage is low (near 0 v), it may not be possible to reach full scale without distortion. use a higher gain setting or a lower input level to avoid distortion. when using the ad9271 evaluation board or system level design, 1. click new dut ( ) in the spi controller software. 2. in the global tab of spi controller, find the chip grade(2) box and use the drop-down menu to select the correct speed grade. 3. in the adcglobal 0 tab of spi controller, find the highpass(2b) box and select the manual tune box to calibrate the antialiasing filter. 9. right-click the fft plot and select comments . use this box to record information such as the serial number of the board, the channel, the input and clock frequencies, the gain pins voltage, and the date. press the print screen key and save the fft screenshot if desired.
ad9271 rev. b | page 45 of 60 06304-086 schematics and artwork ain chb ain cha ain chc ain chd 6 14 2 5 3 t10 4 adt1-1wt + 3 52 4 1 6 adt1-1wt + t10 2 3 52 4 1 6 adt1-1wt + t10 3 6 14 2 5 3 t10 1 adt1-1wt + r12 2 0-dn p 0-dn p r11 3 r15 0 0-dn p r10 4 0-dn p ct d ct c ct b ct a r16 0 49.9 c11 5 0.1uf 0.1uf c12 4 r12 1 0 c10 6 22pf 0.1uf-dn p c10 8 22pf c10 2 c10 4 0.1uf-dn p c12 0 0.1uf-dn p 0.1uf-dn p c11 9 c11 8 0.1uf-dn p 0.1uf-dn p c11 7 gnd d gnd a j10 1 r12 8 49.9-dn p 49.9-dn p r11 9 49.9-dn p r11 0 r10 1 49.9-dn p lga li a losw a lo- a 0 r10 5 r10 8 200 r10 7 1k-dn p c10 3 0.1uf 0-dn p r15 4 0-dn p r10 9 r10 6 0 0 r13 0 r10 2 0 r14 9 0 avd d 10k-dn p r14 2 r14 1 10k-dn p 49.9 r15 8 ct a 0 r13 7 r13 2 0 0.1uf c12 1 c10 1 0.1uf 0.1uf c10 5 c12 2 0.1uf 0 r16 2 r11 2 0 gnd b j10 2 ct b r15 9 49.9 10k-dn p r14 3 r14 4 10k-dn p avd d 0 r13 8 0 r11 1 r15 1 0 0 r11 5 r11 8 0-dn p r15 5 0-dn p 0.1uf c10 7 1k-dn p r11 6 200 r11 7 r11 4 0 lo- b losw b li b lgb lgd li d losw d lo- d 0 r12 3 r13 5 200 r13 4 1k-dn p 0-dn p r15 7 0-dn p r13 6 r13 3 0 0 r15 3 r12 9 0 r14 0 0 avd d 10k-dn p r14 8 r14 7 10k-dn p 49.9 r16 1 ct d j10 4 0 r13 1 r16 4 0 c11 3 0.1uf 0.1uf c10 9 c12 3 0.1uf 0 r16 3 gnd c j10 3 ct c 10k-dn p r14 5 r14 6 10k-dn p avd d 0 r13 9 0 r10 3 r15 2 0 0 r124 r127 0-dn p r15 6 0-dn p 0.1uf c11 1 1k-dn p r12 5 200 r12 6 r12 0 0 lo- c losw c li c lg c c11 2 0.1uf-dn p 22pf c11 0 c11 4 22pf 0.1uf-dn p c11 6 figure 75. evaluation board schematic, dut analog input circuits
ad9271 rev. b | page 46 of 60 06304-087 ain che ain chf 0-dn p r22 2 r21 2 0-dn p j20 1 49 r2 r2 0 j20 2 0 r2 ain chg ain chh 3 52 4 1 6 adt1-1wt + t20 4 6 14 2 5 3 t20 2 adt1-1wt + 6 14 2 5 3 t20 3 adt1-1wt + 3 52 4 1 6 adt1-1wt + t20 1 0-dn p r24 1 r23 1 0-dn p ct h ct g ct f ct e 49.9-dn p r21 9 r20 8 200 c21 0 22pf c21 6 0.1uf-dn p 22pf c21 4 0.1uf-dn p c21 2 22pf c20 6 c20 8 0.1uf-dn p 0.1uf-dn p c22 0 c21 9 0.1uf-dn p 0.1uf-dn p c21 8 c21 7 0.1uf-dn p r24 2 10k-dn p 0-dn p r25 4 c20 1 0.1uf r20 1 49.9-dn p .9-dn p 1 0 r22 8 49.9-dn p gnd h ct h ct g gnd g gnd f ct f ct e gnd e lg e li e losw e lo- e 0 r20 5 r20 7 1k-dn p c20 3 0.1uf 0-dn p r20 9 r20 6 0 0 r24 9 r20 2 0 r20 3 0 avd d 10k-dn p r24 3 49.9 r25 8 0 r22 1 r23 2 0 0.1uf c22 1 0.1uf c20 5 c22 2 0.1uf 0 r26 2 3 0 r25 9 49.9 10k-dn p r20 4 r24 4 10k-dn p avd d 3 8 0 r21 1 r25 0 0 0 r21 5 r21 8 0-dn p r25 5 0-dn p 0.1uf c20 7 1k-dn p r21 6 200 r21 7 r21 4 0 lo- f losw f li f lgf lgh li h losw h lo- h 0 r22 3 r23 5 200 r23 4 1k-dn p c21 5 0.1uf 0-dn p r25 7 0-dn p r23 6 r23 3 0 0 r25 2 r22 9 0 r24 0 0 avd d 10k-dn p r24 8 r24 7 10k-dn p 49.9 r26 1 j20 4 0 r25 3 r26 4 0 0.1uf c22 4 c21 3 0.1uf 0.1uf c20 9 c22 3 0.1uf 0 r26 3 r23 7 0 j20 3 r26 0 49.9 10k-dn p r24 5 r24 6 10k-dn p avd d 0 r23 9 0 r21 3 r25 1 0 0 r224 r227 0-dn p r25 6 0-dn p 0.1uf c21 1 1k-dn p r22 5 200 r22 6 r22 0 0 lo- g losw g li g lg g c20 2 22pf 0.1uf-dn p c20 4 figure 76. evaluation board schematic, dut analog input circuits (continued)
ad9271 rev. b | page 47 of 60 0 6304-088 cw cw v- v+ trim/n c ad9271bsvz-50 clk+ clk- csb cwd0 + cwd0- cwd1 + cwd1- cwd2 + cwd2- cwd3 + cwd3- cwd4 + cwd4- cwd5 + cwd5- cwvd d doutc + doutd + do u t f + doutg + douth + doutc - doutd - do u t f - doutg - douth - dco+ dco- douta + do u t a - doutb + doutb - doute + doute - drvdd fco+ fco- gain + gain - lga lgb lgc lgd lge lgf lgg lgh lia lib lic lid lie lif lig lih lo-a lo-b lo-c lo-d lo- e lo-f lo-g lo-h losw a losw b losw c losw d losw e losw f losw g losw h pad pdw n ravdd rbias refb reft sclk sdio sens e stdby vref avd d avd d avd d avd d avd d avd d avd d avd d avd d avd d drvdd avd d avd d avd d avd d avd d avd d avd d avd d gain drive input vref selec t vref=0.5v(1+r313/r312) vref = external vref=1v remove c307 when using external vref reference circuitry 26 54 60 66 72 55 61 67 73 53 79 78 81 80 83 82 94 93 96 95 98 97 84 46 44 42 40 34 32 30 28 45 43 41 39 33 31 29 27 36 35 47 50 38 37 86 85 56 62 68 74 57 63 69 75 59 65 71 77 99 58 64 70 76 49 92 91 88 87 51 52 90 48 89 100 101 2 1 3 u302 adr510art z 8.06 k r33 5 r32 5 1k 2 1 p303 1k r30 9 r33 7 0-dn p c301 0.1uf c30 5 0.1u f vref_du t 470k r308 4.7uf c302 0.1u f c30 8 r33 8 10k 1k r32 6 r30 2 49.9 r30 4 00 r33 1 ggn d r31 9 1k 0.1uf c303 c304 0.1uf c30 9 0.1u f 1 2 p302 vsense_du t r313 dnp avd d r317 0 dnp r312 r311 0-dn p avd d 10k r31 0 r33 6 10k r30 3 100 sclk_du t csb_du t j301 avd d avd d r30 1 10k avd d in drvdd_dut losw e avdd_3.3v losw d avd d lo-d cwd0- cwd1 + cwd1- cwd0 + cwd2 + cwd2- vsense_dut vref_dut cwd5 + lo-e cwd4- cwd4 + cwd5- cwd3 + cwd3- avd d 10 16 22 4 3 9 15 21 24 23 25 2 8 14 20 1 7 13 19 5 11 17 6 12 18 u301 lgf clk lie lge lif losw f lo-f lig lgg lo-g losw g clk lih lgh losw h lo-h avd d avd d avd d avd d avd d chh chh chf chg chg dco dco fco che che chf chb cha cha drvdd_dut chc chc chb chd chd fco avd d lga lo-a lia losw a lo-b lgc lib losw b lgb lgd lid lo-c lic losw c sdio_du t avd d avd d avd d r315 0-dn p 0-dn p r316 0.1u f c30 6 1uf c30 7 figure 77. evaluation board schematic, dut, vref, and gain circuitry
ad9271 rev. b | page 48 of 60 06304-089 clk clkb gnd gnd_pad out0 out0b out1 out1b rset s0 s1 s10 s2 s3 s4 s5 s6 s7 s8 s9 syncb vref vs signal=dnc;27,28 signal=avdd_3.3v;4,17,20,21,24,26,29,3 0 +in 1 +in2 -in1 -in2 out1 out2 v+ v- ad822art z + - + - gn d t c ou vc tri - stat e aout optional connectio n to ad8339 eval board aout option al clock drive circui t lvdsoutpu t clipsineout (default ) lvpecloutpu t ad9515pin-strapsettings w doppler circuitr y enable disable c enc enc 4 3 vfac3 43 61 2 5 t402 adtt4-1t + 1 2 h-l-50mhz osc401 3 5 2 6 1 7 8 4 u402 3 2 1 cr401 hsms-2812 2 3 31 33 23 22 19 18 32 25 16 7 15 14 13 12 11 10 9 8 5 6 1 u401 ad9515bcpz 1 2 l40 8 560u h 2 1 560u h l40 7 2 1 560u h l40 6 1 2 l40 5 560u h 2 1 560u h l40 2 1 2 l40 1 560u h 2 1 560u h l40 3 1 2 l40 4 560u h 127 r448 r447 127 avdd_3.3v r436 0 r424 0-dnp 0 r425 r427 0 0-dnp r432 0-dnp r426 r452 0 0 r466 0-dnp r406 r402 10k c409 0.1uf 0 r417 6 14 2 5 3 t401 adt1-1w+ 750 r454 r422 100 s0 c401 0.1u f opt_clk opt_clk 0.1u f c411 r415 0 100 r423 240 r421 r420 240 c421 0.1u f 0.1u f c419 c420 0.1u f 0.1u f c422 r411 49.9-dn p 2 4 6 8 avdd_3.3v clk s10 s9 s8 s7 s6 s5 s4 s3 s2 s1 avdd_3.3v avdd_3.3v avdd_3.3v avdd_3.3v avdd_3.3v avdd_3.3v dnp r412 avdd_3.3v 10k r410 dnp r408 r409 dnp opt_clk r407 0-dnp r446 0 0-dnp r459 49. 9 r404 r414 4.12 k avdd_3.3v 0.1uf-dnp c408 c407 0.1uf-dnp c406 0.1uf-dnp 0.1uf-dnp c405 7 5 3 1 p403 clk s10 1 e402 0 r403 clk r418 0 r416 0 c402 0.1uf j402 r455 49. 9 r450 0 avdd_3.3v 10k r401 1 2 3 j401 cwd5- cwd5+ cwd4- cwd4+ cwd1- cwd1+ cwd0- cwd0+ 2 4 6 8 7 5 3 1 p405 avdd_2.5 v +5v r453 750 -5v cwd2 cwd1 0 r451 r449 0-dnp r462 0 0 r460 cwd1 avdd_3.3v cwd2- cwd2+ 0-dnp r465 49. 9 r458 j403 cwd2 r461 0-dnp r463 0 0 r464 r467 750 750 r468 avdd_2.5v avdd_2.5v r469 750 750 r470 avdd_2.5 v 1 3 5 7 8 6 4 2 p406 r405 0 0.1uf c403 0.1uf c410 1 e401 s9 s8 s7 s6 s5 s4 s3 s2 s1 s0 p402 avdd_3.3v ion iop cwd3- cwd3+ p401 clk r413 10k opt_clk avdd_3.3v avdd_3.3v avdd_3.3v avdd_3.3v c414 0.1u f 0.1u f c412 c413 0.1u f 0.1u f c416 c415 0.1u f 0.1u f c417 c418 0.1u f r428 0-dnp r430 0-dnp r434 0-dnp r429 0 0 r431 0 r433 r435 0 0 r439 r441 0 0 r443 r445 0 0-dnp r437 r438 0-dnp 0-dnp r440 r442 0-dnp 0-dnp r444 figure 78. evaluation board schemati c, clock and cw doppler circuitry
ad9271 rev. b | page 49 of 60 06304-090 7.5v power 2.5mm jack 2a y1 vcc y2 a2 gnd a1 y1 vcc y2 a2 gnd a1 sd gnd out in nr in out out adp333 5 bias psg cb cg cg cg gnd output 1 output 4 input gnd output 1 output 4 input gnd input output 1 output 4 +1.8v 6v, 2a ma x populatemh501-504for standardboard evaluation +1.8v power supply inpu t gnd test points board mounting hole s populatemh503-505for dockingwith ad8339eval board spi bus disconnect optio n power input cw +/- 5v spi circuitry from fifo optionalpowerinput +3.3v mh501 mh502 mh503 mh504 mh505 4 2 3 1 adp3339akcz-3.3-r l u705 1 32 4 adp3339akcz-1.8-r l 1 32 4 adp3339akcz-1.8-r l 2 1 d705 s2a-tp 12 d704 s2a-tp 2 1 d703 s2a-tp 12 d702 s2a-tp 1 3 2 4 5 6 l70 1 bnx016-0 1 f70 1 nanosmdc110 f 1 2 3 4 5 6 p501 z5.531.3625. 0 avdd_2.5 v 64 7 1 8 3 2 5 u706 adp3335acpz-2. 5 1 2 3 p511 z5.531.3325. 0 1 2 34 5 6 nc7wz16p6x_n l u703 6 5 4 3 2 1 u702 nc7wz07p6x_n l c704 10u f c50 1 10u f c717 1uf c710 0.1u f cr702 green 24 0 r716 c72 1 100p f c504 0.1u f 0.1u f c502 2 1 d701 c703 0.1u f 10u f c711 c707 10u f 10u f c709 10u f c50 3 1k r710 r711 10 k 1 2 3 p70 1 1 e704 dut_avdd 1 2 l70 5 10u h 1uf c715 2 1 10u h l50 1 1uf c722 c72 3 1uf avdd avdd 0.1u f c73 0 c712 0.1u f 1 e701 dut_drvd d dut_avdd 3.3v_avd d -5v +5v 0.1u f c702 csb_dut avdd sclk_du t 6 8 7 5 avdd sdio_dut avdd_3.3 v 1k r712 r713 1k pwr_out pwr_i n sdi_cha sdo_cha 1 2 l50 2 10u h 1 2 l70 3 10u h avdd_3.3 v 2 1 10u h l70 2 avdd 0.1u f c708 1 2 l70 4 10u h drvdd_dut 1 e702 1 e703 1 e707 1 e706 1 e708 1 e705 c731 0.1u f 0.1u f c733 c732 0.1u f c735 0.1u f 0.1u f c734 c748 0.1u f 0.1u f c746 c747 0.1u f 0.1u f c745 c74 4 0.1u f 0.1u f c74 0 0.1u f c751 avdd_3.3 v drvdd_dut c743 0.1u f c742 0.1u f avdd_3.3 v 2 1 10u h l70 6 dut_drvd d pwr_in c719 1uf 1uf c72 0 1 2 l70 7 10u h 3.3v_avd d r71 5 10k u704 u707 10 k r714 c71 4 1uf pwr_out 2 4 3 1 j501 csb1_cha sclk_ch a 1uf c71 6 pwr_out figure 79. evaluation board schematic, power supply and spi interface circuitry
ad9271 rev. b | page 50 of 60 06304-111 digital outputs a1 b1 gndab 1 a1 0 a2 a3 a4 a5 a6 a7 a8 a9 b1 0 b2 b3 b4 b5 b6 b7 b8 b9 c1 c1 0 c2 c3 c4 c5 c6 c7 c8 c9 d1 d1 0 d2 d3 d4 d5 d6 d7 d8 d9 gndab1 0 gndab 2 gndab 3 gndab 4 gndab 5 gndab 6 gndab 7 gndab 8 gndab 9 gndcd 1 gndcd1 0 gndcd 2 gndcd 3 gndcd 4 gndcd 5 gndcd 6 gndcd 7 gndcd 8 gndcd 9 a1 b1 gndab 1 a1 0 a2 a3 a4 a5 a6 a7 a8 a9 b1 0 b2 b3 b4 b5 b6 b7 b8 b9 c1 c1 0 c2 c3 c4 c5 c6 c7 c8 c9 d1 d1 0 d2 d3 d4 d5 d6 d7 d8 d9 gndab1 0 gndab 2 gndab 3 gndab 4 gndab 5 gndab 6 gndab 7 gndab 8 gndab 9 gndcd 1 gndcd1 0 gndcd 2 gndcd 3 gndcd 4 gndcd 5 gndcd 6 gndcd 7 gndcd 8 gndcd 9 optional output terminations r601-r610 fifo5: data bus 1 connector fifo5: hs - serial/spi/aux connector 10 2 3 4 5 6 7 8 9 20 12 13 14 15 16 17 18 19 31 40 32 33 34 35 36 37 38 39 41 50 42 43 44 45 46 47 48 49 30 22 23 24 25 26 27 28 29 51 60 52 53 54 55 56 57 58 59 p60 1 6469169-1 59 58 57 56 55 54 53 52 60 51 29 28 27 26 25 24 23 22 30 49 48 47 46 45 44 43 42 50 41 39 38 37 36 35 34 33 32 40 31 19 18 17 16 15 14 13 12 20 9 8 7 6 5 4 3 2 10 p60 2 6469169-1 100-dnp r609 r608 100-dnp 100-dnp r607 r606 100-dnp 100-dnp r605 r604 100-dnp 100-dnp r603 r602 100-dnp r601 100-dnp chh sdi_cha sclk_ch 1 11 21 21 11 1 r610 100-dnp a csb1_cha dco chd chg chf che chc chb cha dco fco cha chb chc chd che chf chg chh csb2_cha csb3_cha csb4_cha sdo_cha fco figure 80. evaluation board sche matic, digital output interface
ad9271 rev. b | page 51 of 60 0 6304-084 figure 81. evaluation board layout, top side 0 6304-083 figure 82. evaluation board layout, ground plane (layer 2)
ad9271 rev. b | page 52 of 60 06304-081 figure 83. evaluation board layout, power plane (layer 3) 06304-082 figure 84. evaluation board layout, power plane (layer 4)
ad9271 rev. b | page 53 of 60 4-080 0630 figure 85. evaluation board layout, ground plane (layer 5) 0 6304-085 figure 86. evaluation board layout, bottom side
ad9271 rev. b | page 54 of 60 table 16. evaluation board bill of materials (bom) 1 item qty. reference designator device package description manufacturer rohs part number 1 70 c101, c103, c105, c107, c109, c111, c113, c115, c121, c122, c123, c124, c201, c203, c205, c207, c209, c211, c213, c215, c221, c222, c223, c224, c301, c303, c304, c305, c306, c308, c309, c401, c402, c403, c409, c410, c411, c412, c413, c414, c415, c416, c417, c418, c419, c420, c421, c422, c502, c504, c702, c703, c708, c710, c712, c730, c731, c732, c733, c734, c735, c740, c742, c743, c744, c745, c746, c747, c748, c751 capacitor 402 0.1 f, ceramic, x5r, 10 v, 10% tol panasonic avx murata ecj-0eb1a104k 2 0402yd104kat2a 2 grm155r71c104ka88d 2 2 1 c302 capacitor 603 4.7 f, 6.3 v, x5r, 10% tol avx murata 06036d475kat2a grm188r60j475ke19d 3 9 c307, c714, c715, c716, c717, c719, c720, c722, c723 capacitor 603 1 f, ceramic, x5r, 6.3 v, 10% tol panasonic murata ecj-1vb0j105k 2 grm188r61c105ka93d 2 4 8 c102, c106, c110, c114, c202, c206, c210, c214 capacitor 402 22 pf, ceramic, npo, 5% tol, 50 v kemet avx murata c0402c220j5gactu 2 04025a220jat2a 2 grm1555c1h220jz01d 2 5 1 c721 capacitor 402 100 pf, ceramic, cog, 50 v, 5% tol murata grm1555c1h101jz01d 2 6 1 c704 capacitor 1812 10 f, x5s, 50 v, 20% tol taiyo yuden umk432c106mm-t 2 7 5 c501, c503, c707, c709, c711 capacitor 603 10 f, ceramic, x5r, 6.3 v, 20% tol panasonic murata ecj-1vb0j106m 2 grm188r60j106m 2 8 1 cr401 diode sot23 30 v, 20 ma, dual schottky avago technologies limited (agilent) hsms-2812-tr1g 9 1 cr702 led 603 green, 4 v, 5 m candela panasonic lnj314g8tra 2 10 5 d701, d702, d703, d704, d705 diode do-214ab 3 a, 30 v, smc micro commercial co. s2a-tp 2 11 1 f701 fuse 1210 6.0 v, 2.2 a trip current resettable fuse tyco/raychem nanosmdc110f-2 2 12 8 l401, l402, l403, l404, l405, l406, l407, l408 inductor 1210 560 h, test freq 1 khz, 5% tol, 40 ma murata lqh32mn561j23l 2 13 8 l501, l502, l702, l703, l704, l705, l706, l707 ferrite bead 1210 10 h, test freq 100 mhz, 25% tol, 500 ma murata blm31pg500sh1l 2 14 1 l701 choke coil 5-pin 25 v dc, 15 a, 100 khz to 1 ghz, 40 db insertion loss murata bnx016-01
ad9271 rev. b | page 55 of 60 item qty. reference designator device package description manufacturer rohs part number 15 2 j501, p403 connector 8-pin 100 mil header, male, 2 4 double row straight samtec tsw-104-08-t-d 2 16 2 p302, p303 connector 2-pin 100 mil header jumper, 1 2 samtec tsw-102-07-g-s 2 17 2 p405, p406 connector 8-pin 100 mil header, female, 2 4 double row straight samtec ssw-104-06-g-d 2 18 1 p511 connector 3-pin 3.5 mm header strip, male, 1 3 single row straight wieland z5.531.3325.0 2 19 1 j401 connector 3-pin 100 mil header jumper, 1 3 samtec tsw-103-07-g-s 2 20 13 j101, j102, j103, j104, j201, j202, j203, j204, j301, j402, j403, p401, p402 connector sma side mount sma for 0.063 in. board thickness samtec sma-j-p-h-st-em1 2 21 2 p601, p602 connector header 1469169-1, right angle 2-pair, 25 mm, header assembly tyco/amp 1469169-1 new 6469169-1 22 1 p701 connector 0.08", pcmt rapc722, power supply connector switchcraft rapc722x 2 23 85 r102, r103, r105, r106, r111, r112, r114, r115, r120, r121, r123, r124, r129, r130, r131, r132, r133, r137, r138, r139, r140, r149, r151, r152, r153, r162, r163, r164, r202, r203, r205, r206, r211, r213, r214, r215, r220, r221, r223, r224, r229, r230, r232, r233, r237, r238, r239, r240, r249, r250, r251, r252, r253, r262, r263, r264, r304, r317, r331, r403, r405, r415, r416, r417, r418, r425, r427, r429, r431, r433, r435, r436, r439, r441, r443, r445, r446, r450, r451, r452, r460, r462, r463, r464, r466 resistor 402 0 , 1/16 w, 5% tol panasonic koa yageo nic components erj-2ge0r00x 2 rk73z1ettp 2 rc0402jr-070rl 2 nrc04z0trf 2 24 8 r108, r117, r126, r135, r208, r217, r226, r235 resistor 402 200 , 1/16 w, 5% tol nic components nrc04j201trf 2 25 12 r158, r159, r160, r161, r258, r259, r260, r261, r302, r404, r455, r458 resistor 402 49.9 , 1/16 w, 0.5% tol susumu co. rr0510r-49r9-d 2 26 9 r301, r338, r401, r402, r410, r413, r711, r714, r715 resistor 402 10 k, 1/16 w, 5% tol panasonic koa yageo nic components erj-2gej103x 2 rk73b1ettp103j 2 rc0402jr-0710kl 2 nrc04j103trf 2
ad9271 rev. b | page 56 of 60 item qty. reference designator device package description manufacturer rohs part number 27 3 r303, r422, r423 resistor 402 100 , 1/16 w, 1% tol panasonic koa yageo erj-2rkf1000x 2 rk73h1ettp1000f 2 rc0402fr-07100rl 2 nrc04f1000trf 2 28 7 r309, r319, r325, r326, r710, r712, r713 resistor 402 1 k, 1/16 w, 1% tol panasonic koa yageo nic components erj-2rkf1001x 2 rk73h1ettp1001f 2 rc0402fr-071kl 2 nrc04f1001trf 2 29 1 r308 resistor 402 470 k, 1/16 w, 5% tol panasonic koa yageo nic components erj-2gej474x 2 rk73b1ettp474j 2 rc0402jr-07470kl 2 nrc04j474trf 2 30 2 r310, r336 potentiometer 3-lead 10 k, cermet trimmer potentiometer, 18-turn top adjust, 10%, 1/2 w murata pva2a103a01r00 2 31 1 r414 resistor 402 4.12 k, 1/16 w, 1% tol panasonic nic components erj-2rkf4121x 2 nrc04f4121trf 2 32 3 r420, r421, r716 resistor 402 240 , 1/16 w, 5% tol yageo nic components rc0402jr-07240rl 2 nrc04j241trf 2 33 1 r335 resistor 402 8.06 k, 1/16 w, 1% tol nic components nrc04f8061trf 2 34 2 r447, r448 resistor 402 127 , 1/16 w, 1% tol nic components nrc04f1270trf 2 35 6 r453, r454, r467, r468, r469, r470 resistor 402 750 , 1/16 w, 5% tol nic components nrc04j751trf 2 36 1 osc401 oscillator surface mount osc clock 50.000 mhz smd valpey fisher cts vfac3-bhl-50mhz cb3lv-3c-50m0000-t 37 9 t101, t102, t103, t104, t201, t202, t203, t204, t401 transformer cd542 75 , 1:1 impedance ratio transformer, 0.4 mhz to 800 mhz mini-circuits? adt1-1wt+ 38 1 t402 transformer cd637 50 , 1:4 impedance ratio transformer, 0.2 mhz to 120 mhz mini-circuits adtt4-1+ 39 1 u301 ic sv-100-3 octal lna/vga/ aaf/adc and crosspoint switch analog devices ad9271bsvz-50 40 1 u302 ic sot23 1.0 v precision low noise shunt voltage reference analog devices adr510artz 41 1 u401 ic lfcsp32-5x5 clock dist. analog devices ad9515bcpz
ad9271 rev. b | page 57 of 60 item qty. reference designator device package description manufacturer rohs part number 42 1 u402 ic so8 dual current feedback op amp, so8 analog devices ad812arz 43 1 u706 ic cp-8 500 ma, low noise, low dropout reg analog devices adp3335acpz-2.5 44 2 u704, u707 ic sot223-2 regulator analog devices adp3339akcz-1.8 45 1 u705 ic sot223-2 regulator analog devices adp3339akcz-3.3 46 1 u702 ic sc88 nc7wz07, dual buffer, sc88 fairchild nc7wz07p6x_nl 2 47 1 u703 ic sc88 nc7wz16p6x, uhs dual buffer, sc88 fairchild nc7wz16p6x_nl 2 1 this bom is rohs compliant. 2 may use suitable alternative.
ad9271 rev. b | page 58 of 60 compliant to jedec standards ms-026-aed-hd 0.27 0.22 0.17 outline dimensions 1 25 26 50 76 100 75 51 14.00 bsc sq 16.00 bsc sq 0.50 bsc lead pitch 0.75 0.60 0.45 1.20 max 1 25 26 50 76 100 75 51 pin 1 9.50 sq top view (pins down) bottom view (pins up) 1.05 1.00 0.95 0.20 0.09 0.08 max coplanarity 0 min 7 3.5 0 view a rotated 90 ccw seating plane 0.15 0.05 view a exposed pad notes: the package has a conductive heat slug to help dissipate heat and ensure reliable operation of the device over the full industrial temperature range. the slug is exposed on the bottom of the package and electrically connected to chip ground. it is recommended that no pcb signal traces or vias be located under the package that could come in contact with the conductive slug. attaching the slug to a ground plane will reduce the junction temperature of the device which may be beneficial in high temperature environments. 080706-a figure 87. 100-lead thin quad flat package, exposed pad [tqfp_ep] (sv-100-3) dimensions shown in millimeters ordering guide model temperature range package description package option ad9271bsvz-50 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] sv-100-3 ad9271bsvzrl-50 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] tape and reel sv-100-3 ad9271bsvz-40 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] sv-100-3 ad9271bsvzrl-40 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] tape and reel sv-100-3 ad9271bsvz-25 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] sv-100-3 ad9271bsvzrl-25 1 ?40c to +85c 100-lead thin quad flat package, exposed pad [tqfp_ep] tape and reel sv-100-3 1 z = rohs compliant part.
ad9271 rev. b | page 59 of 60 notes
ad9271 rev. b | page 60 of 60 notes ?2007C2009 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. d06304-0-5/09(b)

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