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FEATURES AD5544 16-Bit Resolution AD5554 14-Bit Resolution 2 mA Full-Scale Current 20%, with VREF = 10 V 2 s Settling Time V SS BIAS for Zero-Scale Error Reduction @ Temp Midscale or Zero-Scale Reset Four Separate 4Q Multiplying Reference Inputs SPI-Compatible 3-Wire Interface Double Buffered Registers Enable Simultaneous Multichannel Change Internal Power ON Reset Compact SSOP-28 Package APPLICATIONS Automatic Test Equipment Instrumentation Digitally-Controlled Calibration
Quad, Current-Output Serial-Input, 16-Bit/14-Bit DACs AD5544/AD5554
FUNCTIONAL BLOCK DIAGRAM
VREF A B C D
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 A0 A1 VDD RFBA INPUT REGISTER R DAC A REGISTER R DAC A IOUTA AGNDA RFBB 16 INPUT REGISTER R DAC B REGISTER R DAC B IOUTB AGNDB RFBC INPUT REGISTER R DAC C REGISTER R DAC C IOUTC AGNDC CS CLK EN DAC A B C D 2:4 DECODE INPUT REGISTER R DAC D REGISTER R DAC D RFBD IOUTD AGNDD POWERON RESET
SDO
SDI
AD5544
AGNDF
DGND
RS
MSB
LDAC
VSS
GENERAL DESCRIPTION
The AD5544/AD5554 quad, 16-/14-bit, current-output, digitalto-analog converters are designed to operate from a single 5 V supply. The applied external reference input voltage (VREF) determines the full-scale output current. Integrated feedback resistors (RFB) provide temperature-tracking, full-scale voltage outputs when combined with an external I-to-V precision amplifier. A doubled-buffered serial-data interface offers high-speed, 3-wire, SPI- and microcontroller-compatible inputs using serial-data-in (SDI), clock (CLK), and a chip-select (CS). In addition, a serial-data-out pin (SDO) allows for daisy-chaining when multiple packages are used. A common level-sensitive load-DAC strobe (LDAC) input allows simultaneous update of all DAC outputs from previously loaded input registers. Additionally, an internal power ON reset forces the output voltage to zero at system turn ON. An MSB pin allows system reset assertion (RS) to force all registers to zero code when MSB = 0, or to half-scale code when MSB = 1. AD5544/AD5554 are packaged in the compact SSOP-28.
1.0 0.5 0.0 -0.5 -1.0 1.0 0.5 0.0
INL - LSB
DAC A
DAC B
-0.5 -1.0 1.0 0.5 0.0 -0.5 -1.0 1.0 0.5 0.0 -0.5 -1.0 0 8192 16384 24576 32768 40960 49152 57344 65536 CODE - Decimal
DAC C
DAC D
Figure 1. AD5544 INL vs. Code Plot (TA = 25C)
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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 which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 2000
5 10%, 0 I X= X= AD5544/AD5554-SPECIFICATIONS (@ VA, B,=C, VD = 10 V, TV ==FullV,OperatingVirtual GND, A Range,0 V, V Temperature
DD SS OUT GND
AD5544 ELECTRICAL CHARACTERISTICS
Parameter STATIC PERFORMANCE Resolution Relative Accuracy Differential Nonlinearity Output Leakage Current Full-Scale Gain Error Full-Scale Tempco2 Feedback Resistor REFERENCE INPUT VREFX Range Input Resistance Input Resistance Match Input Capacitance2 ANALOG OUTPUT Output Current Output Capacitance2 LOGIC INPUTS AND OUTPUT Logic Input Low Voltage Logic Input High Voltage Input Leakage Current Input Capacitance2 Logic Output Low Voltage Logic Output High Voltage INTERFACE TIMING Clock Width High Clock Width Low CS to Clock Setup Clock to CS Hold Clock to SDO Prop Delay Load DAC Pulsewidth Data Setup Data Hold Load Setup Load Hold SUPPLY CHARACTERISTICS Power Supply Range Positive Supply Current Negative Supply Current Power Dissipation Power Supply Sensitivity
2, 3 1
REF
A
unless otherwise noted.)
Min Typ Max 16 4 1.5 10 20 3 8 +15 8 Unit Bits LSB LSB nA nA mV ppm/C k V k % pF mA pF V V A pF V V ns ns ns ns ns ns ns ns ns ns V A A mW %/%
Symbol N INL DNL IOUTX IOUTX GFSE TCVFS RFBX VREFX RREFX RREFX CREFX IOUTX COUTX VIL VIH IIL CIL VOL VOH tCH tCL tCSS tCSH tPD tLDAC tDS tDH tLDS tLDH VDD RANGE IDD ISS PDISS PSS
Condition 1 LSB = VREF/216 = 153 V when VREF = 10 V Data = 0000H, TA = 25C Data = 0000H, TA = TA Max Data = FFFFH VDD = 5 V
4 -15 4
0.75 1 6
Channel-to-Channel
6 1 5
Data = FFFFH Code-Dependent
1.25 80
2.5
0.8 2.4 1 10 0.4 4 25 25 0 25 2 25 20 20 5 25 4.5 Logic Inputs = 0 V Logic Inputs = 0 V, VSS = -5 V Logic Inputs = 0 V VDD = 5% 50 0.001
IOL = 1.6 mA IOH = 100 A
20
5.5 250 1 1.25 0.006
NOTES 1 All static performance tests (except I OUT) are performed in a closed-loop system using an external precision OP177 I-to-V converter amplifier. The AD5544 RFB terminal is tied to the amplifier output. Typical values represent average readings measured at 25 C. 2 These parameters are guaranteed by design and not subject to production testing. 3 All input control signals are specified with t R = t F = 2.5 ns (10% to 90% of 3 V) and timed from a voltage level of 1.5 V. Specifications subject to change without notice.
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AD5544/AD5554 AD5544 ELECTRICAL CHARACTERISTICS
Parameter
1
(@ VDD = 5 V 10%, VSS = -300 mV, IOUTX = Virtual GND, AGNDX = 0 V, VREFA, B, C, D = 10 V, TA = full operating temperature range, unless otherwise noted.)
Min Typ Max Unit 1 2 2 1.2 -65 -90 5 -90 7 s s MHz nV-s dB dB nV-s dB nV/Hz
Symbol
Condition
AC CHARACTERISTICS Output Voltage Settling Time tS
To 0.1% of Full Scale, Data = 0000H to FFFFH to 0000H Output Voltage Settling Time tS To 0.0015% of Full Scale, Data = 0000H to FFFFH to 0000H Reference Multiplying BW BW -3 dB VREFX = 100 mV rms, Data = FFFFH, CFB = 15 pF DAC Glitch Impulse Q VREFX = 10 V, Data 0000H to 8000H to 0000H Feedthrough Error VOUTX/VREFX Data = 0000H, VREFX = 100 mV rms, f = 100 kHz Crosstalk Error VOUTA/VREFB Data = 0000H, VREFB = 100 mV rms, Adjacent Channel, f = 100 kHz Digital Feedthrough Q CS = 1, and fCLK = 1 MHz Total Harmonic Distortion THD VREF = 5 V p-p, Data = FFFFH, f = 1 kHz Output Spot Noise Voltage eN f = 1 kHz, BW = 1 Hz
NOTES 1 All ac characteristic tests are performed in a closed-loop system using an OP42 I-to-V converter amplifier. Specifications subject to change without notice.
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AD5544/AD5554-SPECIFICATIONS
AD5554 ELECTRICAL CHARACTERISTICS
Parameter STATIC PERFORMANCE Resolution Relative Accuracy Differential Nonlinearity Output Leakage Current Full-Scale Gain Error Full-Scale Tempco2 Feedback Resistor REFERENCE INPUT VREFX Range Input Resistance Input Resistance Match Input Capacitance2 ANALOG OUTPUT Output Current Output Capacitance2 LOGIC INPUTS AND OUTPUT Logic Input Low Voltage Logic Input High Voltage Input Leakage Current Input Capacitance2 Logic Output Low Voltage Logic Output High Voltage INTERFACE TIMING Clock Width High Clock Width Low CS to Clock Setup Clock to CS Hold Clock to SDO Prop Delay Load DAC Pulsewidth Data Setup Data Hold Load Setup Load Hold SUPPLY CHARACTERISTICS Power Supply Range Positive Supply Current Negative Supply Current Power Dissipation Power Supply Sensitivity
2, 3 1
(@ VDD = 5 V 10%, VSS = 0 V, IOUTX = Virtual GND, AGNDX = 0 V, VREFA, B, C, D = 10 V, TA = full operating temperature range, unless otherwise noted.)
Min Typ Max 14 1 1 10 20 10 8 +15 8 Unit Bits LSB LSB nA nA mV ppm/C k V k % pF mA pF V V A pF V V ns ns ns ns ns ns ns ns ns ns V A A mW %/%
Symbol N INL DNL IOUTX IOUTX GFSE TCVFS RFBX VREFX RREFX RREFX CREFX IOUTX COUTX VIL VIH IIL CIL VOL VOH tCH tCL tCSS tCSH tPD tLDAC tDS tDH tLDS tLDH VDD RANGE IDD ISS PDISS PSS
Condition 1 LSB = VREF/214 = 610 V when VREF = 10 V Data = 0000H, TA = 25C Data = 0000H, TA = TA Max Data = 3FFFH VDD = 5 V
4 -15 4
2 1 6
Channel-to-Channel
6 1 5
Data = 3FFFH Code-Dependent
1.25 80
2.5
0.8 2.4 1 10 0.4 4 25 25 0 25 2 25 20 20 5 25 4.5 Logic Inputs = 0 V Logic Inputs = 0 V, VSS = -5 V Logic Inputs = 0 V VDD = 5% 50 0.001
IOL = 1.6 mA IOH = 100 A
20
5.5 250 1 1.25 0.006
NOTES: 1 All static performance tests (except I OUT) are performed in a closed-loop system using an external precision OP177 I-to-V converter amplifier. The AD5554 RFB terminal is tied to the amplifier output. Typical values represent average readings measured at 25 C. 2 These parameters are guaranteed by design and not subject to production testing. 3 All input control signals are specified with t R = tF = 2.5 ns (10% to 90% of 3 V) and timed from a voltage level of 1.5 V. Specifications subject to change without notice.
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AD5544/AD5554 AD5554 ELECTRICAL CHARACTERISTICS
Parameter
1
(@ VDD = 5 V 10%, VSS = -300 mV, IOUTX = Virtual GND, AGNDX = 0 V, VREFA, B, C, D = 10 V, TA = full operating temperature range, unless otherwise noted.)
Min Typ Max Unit 1 2 2 1.2 -65 -90 5 -90 7 s s MHz nV-s dB dB nV-s dB nV/Hz
Symbol
Condition
AC CHARACTERISTICS Output Voltage Settling Time tS
To 0.1% of Full Scale, Data = 0000H to 3FFFH to 0000H Output Voltage Settling Time tS To 0.0015% of Full Scale, Data = 0000H to 3FFFH to 0000H Reference Multiplying BW BW -3 dB VREFX = 100 mV rms, Data = 3FFFH, CFB = 15 pF DAC Glitch Impulse Q VREFX = 10 V, Data 0000H to 2000H to 0000H Feedthrough Error VOUTX/VREFX Data = 0000H, VREFX = 100 mV rms, f = 100 kHz Crosstalk Error VOUTA/VREFB Data = 0000H, VREFB = 100 mV rms, Adjacent Channel, f = 100 kHz Digital Feedthrough Q CS = 1, and fCLK = 1 MHz Total Harmonic Distortion THD VREF = 5 V p-p, Data = 3FFFH, f = 1 kHz Output Spot Noise Voltage eN f = 1 kHz, BW = 1 Hz
NOTES: 1 All ac characteristic tests are performed in a closed-loop system using an OP42 I-to-V converter amplifier. Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*
VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 V, +8 V VSS to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V, -7 V VREF to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . -18 V, +18 V Logic Inputs and Output to GND . . . . . . . . . . . . -0.3 V, +8 V V(IOUT) to GND . . . . . . . . . . . . . . . . . . . . -0.3 V, VDD + 0.3 V AGNDX to DGND . . . . . . . . . . . . . . . . . . . . . . -0.3 V, + 0.3 V Input Current to Any Pin Except Supplies . . . . . . . . . 50 mA Package Power Dissipation . . . . . . . . . . . . (TJ MAX - TA)/JA Thermal Resistance JA 28-Lead Shrink Surface-Mount (RS-28) . . . . . . . . 100C/W Maximum Junction Temperature (TJ MAX) . . . . . . . . . 150C
Operating Temperature Range Model A . . . . . . . . . . . . . . . . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . . -65C to +150C Lead Temperature: RS-28 (Vapor Phase, 60 secs) . . . . . . . . . . . . . . . . . . 215C RS-28 (Infrared, 15 secs) . . . . . . . . . . . . . . . . . . . . . . 220C
*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 sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ORDERING GUIDE
Model AD5544ARS AD5554BRS
RES Bit 16 14
INL LSB 4 1
DNL LSB 1.5 1
Temperature Range -40/+85C -40/+85C
Package Description SSOP-28 SSOP-28
Package Option RS-28 RS-28
The AD5544/AD5554 contain 4196 transistors. The die size is 122 mil x 204 mil.
CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD5544/AD5554 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
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AD5544/AD5554
SDI A1 A0 D15 D14 D13 D12 D11 D10 D1 D0 INPUT REG LD
CLK
CS
tCSS
tDS
tDH
tCH
tCL
tCSH
LDAC
tLDS tPD
SDO
tLDH
tLDAC
Figure 2. AD5544 Timing Diagram
SDI
A1
A0
D13
D12
D11
D10
D09
D08
D1
D0 INPUT REG LD
CLK
CS
tCSS
tDS
tDH
tCH
tCL
tCSH
LDAC
tLDS tPD
SDO
tLDH
tLDAC
Figure 3. AD5554 Timing Diagram
Table I. AD5544 Control-Logic Truth Table
CS H L L L + H H H H H
CLK X L + H L X X X X X
LDAC H H H H H L H + H H
RS H H H H H H H H L L
MSB X X X X X X X X 0 H
Serial Shift Register Function No Effect No Effect Shift-Register-Data Advanced One Bit No Effect No Effect No Effect No Effect No Effect No Effect No Effect
Input Register Function DAC Register Latched Latched Latched Latched Selected DAC Updated with Current SR Contents Latched Latched Latched Latched Data = 0000H Latched Data = 8000H Latched Latched Latched Latched Latched Transparent Latched Latched Latched Data = 0000H Latched Data = 8000H
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AD5544/AD5554
Table II. AD5554 Control-Logic Truth Table
CS H L L L + H H H H H
CLK X L + H L X X X X X
LDAC H H H H H L H + H H
RS H H H H H H H H L L
MSB X X X X X X X X 0 H
Serial Shift Register Function No Effect No Effect Shift-Register-Data Advanced One Bit No Effect No Effect No Effect No Effect No Effect No Effect No Effect
Input Register Function DAC Register Latched Latched Latched Latched Selected DAC Updated with Current SR Contents Latched Latched Latched Latched Data = 0000H Latched Data = 2000H Latched Latched Latched Latched Latched Transparent Latched Latched Latched Data = 0000H Latched Data = 2000H
NOTES 1. SR = Shift Register. 2. + positive logic transition; X = Don't Care. 3. At power ON both the Input Register and the DAC Register are loaded with all zeros. 4. For AD5544, data appears at the SDO Pin 19 clock pulses after input at the SDI pin. 5. For AD5554, data appears at the SDO Pin 17 clock pulses after input at the SDI pin.
Table III. AD5544 Serial Input Register Data Format, Data Is Loaded in the MSB-First Format
MSB Bit Position B17 Data Word A1 B16 A0 B15 D15 B14 D14 B13 D13 B12 D12 B11 D11 B10 D10 B9 D9 B8 D8 B7 D7 B6 D6 B5 D5 B4 D4 B3 D3 B2 D2
LSB B1 B0 D1 D0
NOTE Only the last 18 bits of data clocked into the serial register (Address + Data) are inspected when the CS line's positive edge returns to logic high. At this point an internally generated load strobe transfers the serial register data contents (Bits D15-D0) to the decoded DAC-Input-Register address determined by bits A1 and A0. Any extra bits clocked into the AD5544 shift register are ignored, only the last 18 bits clocked in are used. If double-buffered data is not needed, the LDAC pin can be tied logic low to disable the DAC Registers.
Table IV. AD5554 Serial Input Register Data Format, Data Is Loaded in the MSB-First Format
MSB Bit Position B15 Data Word A1 B14 A0 B13 D13 B12 D12 B11 D11 B10 D10 B9 D9 B8 D8 B7 D7 B6 D6 B5 D5 B4 D4 B3 D3 B2 D2 B1 D1
LSB B0 D0
NOTE Only the last 16 bits of data clocked into the serial register (Address + Data) are inspected when the CS line's positive edge returns to logic high. At this point an internally generated load strobe transfers the serial register data contents (Bits D13-D0) to the decoded DAC-Input-Register address determined by bits A1 and A0. Any extra bits clocked into the AD5554 shift register are ignored, only the last 16 bits clocked in are used. If double-buffered data is not needed, the LDAC pin can be tied logic low to disable the DAC Registers.
Table V. Address Decode
A1 0 0 1 1
A0 0 1 0 1
DAC Decoded DAC A DAC B DAC C DAC D
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AD5544/AD5554
AD5544/AD5554 PIN FUNCTION DESCRIPTIONS
Pin # Name 1 2 3 4 5 6 AGNDA IOUTA VREFA RFBA MSB RS
Function DAC A Analog Ground. DAC A Current Output. DAC A Reference Voltage Input Terminal. Establishes DAC A full-scale output voltage. Pin can be tied to VDD pin. Establish Voltage Output for DAC A by Connecting to External Amplifier Output. MSB Bit Set Pin During a Reset Pulse (RS) or at System Power ON if Tied to Ground or VDD. Reset Pin, Active Low Input. Input registers and DAC registers are set to all zeros or half-scale code (8000H for AD5544 and 2000H for AD5554) determined by the voltage on the MSB pin. Register Data = 0000H when MSB = 0. Register Data = 8000H for AD5544 and 2000H for AD5554 when MSB = 1. Positive Power Supply Input. Specified range of operation 5 V 10%. Chip Select, Active Low Input. Disables shift register loading when high. Transfers serial register data to the Input Register when CS/LDAC returns High. Does not effect LDAC operation. Clock Input, Positive Edge Clocks Data into Shift Register. Serial Data Input, Input Data Loads Directly into the Shift Register. Establish Voltage Output for DAC B by Connecting to External Amplifier Output. DAC B Reference Voltage Input Terminal. Establishes DAC B full-scale output voltage. Pin can be tied to VDD pin. DAC B Current Output. DAC B Analog Ground. DAC C Analog Ground. DAC C Current Output. DAC C Reference Voltage Input Terminal. Establishes DAC C full-scale output voltage. Pin can be tied to VDD pin. Establish voltage output for DAC C by connecting to external amplifier output. No Connect. Leave pin unconnected. Serial Data Output, input data loads directly into the shift register. Data appears at SDO, 19 clock pulses for AD5544 and 17 clock pulses for AD5554 after input at the SDI pin. Load DAC Register Strobe, Level Sensitive Active Low. Transfers all Input Register data to DAC registers. Asynchronous active low input. See Control Logic Truth Table for operation. High Current Analog Force Ground. Negative Bias Power Supply Input. Specified range of operation -0.3 V to -5.5 V. Digital Ground Pin. Establish Voltage Output for DAC D by Connecting to External Amplifier Output. DAC D Reference Voltage Input Terminal. Establishes DAC D full-scale output voltage. Pin can be tied to VDD pin. DAC D Current Output. DAC D Analog Ground.
AD5544/AD5554 PIN CONFIGURATION
AGNDA 1 IOUTA 2 VREFA 3 RFBA 4 MSB 5 RS 6 VDD 7
28 27 26 25 24
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
VDD CS CLK SDI RFBB VREFB IOUTB AGNDB AGNDC IOUTC VREFC RFBC NC SDO LDAC AGNDF VSS DGND RFBD VREFD IOUTD AGNDD
AGNDD IOUTD VREFD RFBD DGND VSS
AD5544/ AD5554
23
TOP VIEW 22 AGNDF CS 8 (Not to Scale) 21 LDAC
20 19 18 17 16 15
CLK 9 SDI 10 RFBB 11 VREFB 12 IOUTB 13 AGNDB 14
SDO NC RFBC VREFC IOUTC AGNDC
NC = NO CONNECT
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Typical Performance Characteristics-AD5544/AD5554
0.50 0.25 0.00 -0.25 -0.50 0.50 0.25 0.00
0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75 0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75 0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75 0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75
DAC A
DAC A
DAC B
DNL - LSB
-0.50 0.50 0.25 0.00 -0.25 -0.50 0.50 0.25 0.00 -0.25 -0.50 0 8192
DAC B
DNL - LSB
-0.25
DAC C
DAC C
DAC D
DAC D
16384 24576 32768 40960 49152 57344 65536 CODE - Decimal
0
2048
4096
6144 8192 10240 12288 14336 16384 CODE - Decimal
TPC 1. AD5544 DNL vs. Code (TA = 25C)
TPC 3. AD5554 DNL vs. Code (TA = 25C)
1.0 0.5 0.0 -0.5 -1.0 1.0 0.5 0.0
INL - LSB
DAC A
2.0 INTEGRAL NONLINEARITY ERROR - LSB 1.5 1.0 0.5 0 -0.5 0FFFH -1.0 -1.5 -2.0 -1500 8000H VDD = 5V VREF = 10V TA = 25 C
F000H
DAC B
-0.5 -1.0 1.0 0.5 0.0 -0.5 -1.0 1.0 0.5 0.0 -0.5 -1.0 0 2048 4096 6144 8192 10240 12288 14336 16384 CODE - Decimal
7FFFH
DAC C
-1000
DAC D
0 -500 500 1000 OP AMP OFFSET VOLTAGE - V
1500
TPC 4. AD5544 Integral Nonlinearity Error vs. Op Amp Offset
TPC 2. AD5554 INL vs. Code (TA = 25C)
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AD5544/AD5554
0.75 10.0 VDD = 5V VREF = 10V TA = 25 C 7.5 3000H GAIN ERROR - LSB 5.0 2.5 0.0 -2.5 -5.0 -0.50 -7.5 -0.75 0 500 1000 -2000 -1500 -1000 -500 OP AMP OFFSET VOLTAGE - V -10.0 -1500 VDD = 5V VREF = 10V TA = 25 C
INTEGRAL NONLINEARITY ERROR - LSB
0.50
0.25 2000H 0.00 1FFFH
-0.25
0FFFH
1500
2000
-1000
0 -500 500 OP AMP OFFSET VOLTAGE - V
1000
1500
TPC 5. AD5554 Integral Nonlinearity Error vs. Op Amp Offset
TPC 8. AD5544 Gain Error vs. Op Amp Offset
1.00 DIFFERENTIAL NONLINEARITY ERROR - LSB 0.75 0.50 VDD = 5V VREF = 10V TA = 25 C 8000H
4 3 2 VDD = 5V VREF = 10V TA = 25 C
GAIN ERROR - LSB
1000
0.25 0.00
1 0 -1 -2 -3 -4
F000H
0FFFH -0.25 -0.50 -0.75 -1.00 -1000
-750
0 -500 -250 250 500 OP AMP OFFSET VOLTAGE - V
750
-5 -1500
-1000
0 -500 500 OP AMP OFFSET VOLTAGE - V
1000
1500
TPC 6. AD5544 Differential Nonlinearity Error vs. Op Amp Offset
TPC 9. AD5554 Gain Error vs. Op Amp Offset
0.3
30 VDD = 5V VREF = 10V TA = 25 C 2000H SS = 120 UNITS VDD = 5V VREF = 10V TA = -40 C TO +85 C 20
DIFFERENTIAL NONLINEARITY ERROR - LSB
0.2
0.1
3000H
0.0 0FFFH -0.1 ACCURACY DEGRADATION DUE TO EXTERNAL OP AMP INPUT OFFSET VOLTAGE SPECIFICATION.
FREQUENCY
10 1500 0 0
-0.2
-0.3 -1500
-1000
0 -500 500 1000 OP AMP OFFSET VOLTAGE - V
0.5 1.0 FULL-SCALE TEMPCO - ppm/ C
1.5
TPC 7. AD5554 Differential Nonlinearity Error vs. Op Amp Offset
TPC 10. AD5544 Full-Scale Tempco (ppm/ C)
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AD5544/AD5554
60 SS = 180 UNITS VDD = 5V VREF = 10V TA = -40 C TO +85 C
VOUT (10V/DIV)
40
FREQUENCY
30
VDD = 5V VREF = 10V TA = 25 C AV = -343 1LSB = 52mV
20
VOUT (50mV/DIV)
10
1 s/DIV
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 FULL-SCALE ERROR TEMPCO - ppm/ C 1.8
TPC 11. AD5554 Full-Scale Tempco (ppm/ C)
TPC 14. AD5544 Small Signal Settling Time
7FFFH 8000H
10000
VDD = 5V VREF = 10V TA = 25 C CS (5V/DIV)
VDD = 5V VREF = 10V TA = 25 C
5555H
FFFFH 1000
IDD - A
8000H 0000H
VOUT (50mV/DIV)
100
100ns/DIV
10 1k 10k 100k 1M CLOCK FREQUENCY - Hz 10M 100M
TPC 12. AD5544 Midscale Transition
TPC 15. AD5544 Power Supply Current vs. Clock Frequency
10000 0000H FFFFH VDD = 5V VREF = 10V TA = 25 C VDD = 5V VREF = 10V TA = 25 C 1555H
CS (5V/DIV) 1000
IDD - A
3FFFH 2000H 0000H
VOUT (5V/DIV)
100
2 s/DIV
10 1k 10k 100k 1M CLOCK FREQUENCY - Hz 10M 100M
TPC 13. AD5544 Large Signal Settling Time
TPC 16. AD5554 Power Supply Current vs. Clock Frequency
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AD5544/AD5554
100 90 80 400
PSRR - dB
600 VDD = 5V 10% TA = 25 C VDD = 5V VREF = 10V TA = 25 C
500
70
IDD - A
60 50 40
300
200
100 30 20 100 0 1k 10k 100k CLOCK FREQUENCY - Hz 1M 0 1 2 3 LOGIC INPUT VOLTAGE - Volts 4 5
TPC 17. AD5544/AD5554 Power Supply Rejection vs. Frequency
TPC 19. AD5544/AD5554 Power Supply Current vs. Logic Input Voltage
55 54 53
SUPPLY CURRENT - A
VDD = 5V VREF = 10V LOGIC = VDD
52 51 50 49 48 47 46 -50
-25
0
25 50 75 TEMPERATURE - C
100
125
150
TPC 18. AD5544/AD5554 Power Supply Current vs. Temperature
CIRCUIT OPERATION
The AD5544 and AD5554 contain four, 16-bit and 14-bit, current-output, digital-to-analog converters respectively. Each DAC has its own independent multiplying reference input. Both AD5544/AD5554 use 3-wire SPI compatible serial data interface, with a configurable asynchronous RS pin for half-scale (MSB = 1) or zero-scale (MSB = 0) preset. In addition, an LDAC strobe enables four channel simultaneous updates for hardware synchronized output voltage changes.
D/A Converter Section
with both negative or positive reference voltages. The VDD power pin is only used by the logic to drive the DAC switches ON and OFF. Note that a matching switch is used in series with the internal 5 k feedback resistor. If users are attempting to measure the value of RFB, power must be applied to VDD in order to achieve continuity. An additional VSS bias pin is used to guard the substrate during high temperature applications to minimize zero-scale leakage currents that double every 10C. The DAC output voltage is determined by VREF and the digital data (D) as: VOUT = -VREF x D 65536 D 16384 (For AD5544) (Equation 1)
Each part contains four current-steering R-2R ladder DACs. Figure 4 shows a typical equivalent DAC. Each DAC contains a matching feedback resistor for use with an external I-to-V converter amplifier. The RFBX pin is connected to the output of the external amplifier. The IOUTX terminal is connected to the inverting input of the external amplifier. The AGNDX pin should be Kelvin-connected to the load point in the circuit requiring the full 16-bit accuracy. These DACs are designed to operate
VOUT = -VREF x
(For AD5554)
(Equation 2)
Note that the output polarity is opposite to the VREF polarity for dc reference voltages.
-12-
REV. 0
AD5544/AD5554
VDD VREFX 2R R 2R R 2R R R S2 5k S1 IOUTX AGNDF AGNDX FROM OTHER DACS AGND VSS DGND RFBX
DIGITAL INTERFACE CONNECTIONS OMITTED FOR CLARITY. SWITCHES S1 AND S2 ARE CLOSED, VDD MUST BE POWERED.
FFFFH B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 ZS
GAIN - 12dB/DIV
VDD = 5V VREF = 100mV rms TA = 25 C
Figure 4. Typical Equivalent DAC Channel
These DACs are also designed to accommodate ac reference input signals. Both AD5544/AD5554 will accommodate input reference voltages in the range of -12 V to +12 V. The reference voltage inputs exhibit a constant nominal input resistance of 5 k, 30%. On the other hand, the DAC outputs IOUTA, B, C, D are code-dependent and produce various output resistances and capacitances. The choice of external amplifier should take into account the variation in impedance generated by the AD5544/AD5554 on the amplifiers' inverting input node. The feedback resistance, in parallel with the DAC ladder resistance, dominates output voltage noise. For multiplying mode applications, an external feedback compensation capacitor (CFB) may be needed to provide a critically damped output response for step changes in reference input voltages. Figures 5 and 6 show the gain vs. frequency performance at various attenuation settings using a 23 pF external feedback capacitor connected across the IOUTX and RFBX terminals for AD5544 and AD5554 respectively. In order to maintain good analog performance, power supply bypassing of 0.01 F, in parallel with 1 F, is recommended. Under these conditions, clean power supply with low ripple voltage capability should be used. Switching power supplies is usually not suitable for this application due to the higher ripple voltage and PSS frequency-dependent characteristics. It is best to derive the AD5544/AD5554's 5 V supply from the systems' analog supply voltages. (Do not use the digital 5 V supply.) See Figure 7.
100
1k
10k 100k FREQUENCY - Hz
1M
10M
Figure 5. AD5554 Reference Multiplying Bandwidth vs. Code
3FFFH B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 ZS VDD = 5V VREF = 100mV rms TA = 25 C CF = 23pF 1k 10k 100k FREQUENCY - Hz 1M 10M
GAIN - 12dB/DIV
100
Figure 6. AD5554 Reference Multiplying Bandwidth vs. Code
15V 2R ANALOG POWER SUPPLY
+
R
5V
VDD
AD5544
VREFX 2R R 2R R 2R R R S2 5k 15V S1 IOUTX AGNDF AGNDX FROM OTHER DACS AGND VSS DIGITAL INTERFACE CONNECTIONS OMITTED. FOR CLARITY SWITCHES S1 AND S2 ARE CLOSED, VDD MUST BE POWERED. DGND A1 VCC VOUT VEE RFBX
+
LOAD
Figure 7. Recommended Kelvin-Sensed Hookup
REV. 0
-13-
AD5544/AD5554
VREF A B C D CS EN CLK
AD5544
VDD
SDI
SDO
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 A0 A1
16
RFBA INPUT REGISTER R DAC A REGISTER R DAC A IOUTA AGNDA
RFBB INPUT REGISTER R DAC A B C D 2:4 DECODE RFBC INPUT REGISTER R DAC C REGISTER R DAC C IOUTC AGNDC DAC B REGISTER R DAC B IOUTB AGNDB
RFBD INPUT REGISTER R DAC D REGISTER R DAC D IOUTD AGNDD SET MSB SET MSB
POWERON RESET
AGNDF
DGND
MSB
LDAC
RS
VSS
Figure 8. System Level Digital Interfacing
SERIAL DATA INTERFACE
The AD5544/AD5554 uses a 3-wire (CS, SDI, CLK) SPI compatible serial data interface. Serial data of AD5544 and AD5554 is clocked into the serial input register in an 18-bit and 16-bit data-word format respectively. MSB bits are loaded first. Table II defines the 18 data-word bits for AD5544. Table III defines the 16 data-word bits for AD5554. Data is placed on the SDI pin, and clocked into the register on the positive clock edge of CLK subject to the data setup and data hold time requirements specified in the Interface Timing Specifications. Data can only be clocked in while the CS chip select pin is active low. For AD5544, only the last 18 bits clocked into the serial register will be interrogated when the CS pin returns to the logic high state, extra data bits are ignored. For AD5554, only the last 16 bits clocked into the serial register will be interrogated when the CS pin returns to the logic high state. Since most microcontrollers output serial data in 8-bit bytes, three right-justified data bytes can be written to the AD5544. Keeping the CS line low between the first, second, and third byte transfers will result in a successful serial register update. Similarly, two right-justified data bytes
can be written to the AD5554. Keeping the CS line low between the first and second byte transfer will result in a successful serial register update. Once the data is properly aligned in the shift register, the positive edge of the CS initiates the transfer of new data to the target DAC register, determined by the decoding of address bits A1 and A0. For AD5544, Tables I, III, V, and Figure 2 define the characteristics of the software serial interface. For AD5554, Tables II, IV, V, and Figure 3 define the characteristics of the software serial interface. Figures 8 and 9 show the equivalent logic interface for the key digital control pins for AD5544. AD5554 has similar configuration, except with 14 data bits. Two additional pins RS and MSB provide hardware control over the preset function and DAC Register loading. If these functions are not needed, the RS pin can be tied to logic high. The asynchronous input RS pin forces all input and DAC registers to either the zero-code state (MSB = 0), or the half-scale state (MSB = 1)
-14-
REV. 0
AD5544/AD5554
TO INPUT REGISTER A B C D
APPLICATIONS
CS
ADDRESS DECODER
The AD5544/AD5554 are inherently 2-quadrant multiplying D/A converters. That is, they can be easily set up for unipolar output operation. The full-scale output polarity is the inverse of the reference-input voltage. In some applications it may be necessary to generate the full 4quadrant multiplying capability or a bipolar output swing. This is easily accomplished using an additional external amplifier (A2) configured as a summing amplifier (see Figure 11). In this circuit the first and second amplifiers (A1 and A2) provide a total gain-of-2 which increases the output voltage span to 20 V. Biasing the external amplifier with a 10 V offset from the reference voltage results in a full 4-quadrant multiplying circuit. The transfer equation of this circuit shows that both negative and positive output voltages are created as the input data (D) is incremented from code zero (VOUT = -10 V) to midscale (VOUT = 0 V) to full-scale (VOUT = 10 V).
D VOUT = - 1 x VREF (For AD5544) 32768
EN CLK SDI SDO SHIFT REGISTER
19TH/17TH CLOCK
Figure 9. AD5544/AD5554 Equivalent Logic Interface
POWER-ON RESET
When the VDD power supply is turned ON, an internal reset strobe forces all the Input and DAC registers to the zero-code state or half-scale, depending on the MSB pin voltage. The VDD power supply should have a smooth positive ramp without drooping in order to have consistent results, especially in the region of VDD = 1.5 V to 2.3 V. The VSS supply has no effect on the power-ON reset performance. The DAC register data will stay at zero or half-scale setting until a valid serial register data load takes place.
ESD Protection Circuits
(Equation 3)
All logic-input pins contain back-biased ESD protection Zeners connected to ground (DGND) and VDD as shown in Figure 9.
VDD 5k
D VOUT = - 1 x VREF (For AD5554) 8192
10k 10k 10V VREF 5k A2
(Equation 4)
VOUT
DIGITAL INPUTS
AD588 -10V < VOUT < +10V VDD
DGND
VREFX ONE CHANNEL AD5544
RFBX IOUTX A1 AGNDX
Figure 10. Equivalent ESD Protection Circuits
PCB LAYOUT
VSS
AGNDF
In PCB layout, all analog ground, AGNDX, should be tied together. Amplifiers suitable for I-to-V conversion include: * High Accuracy: OP97, OP297 * Speed and Accuracy: OP42 * 5 V Applications: OP162/OP262/OP462, OP184/OP284/ OP484
DIGITAL INTERFACE CONNECTIONS OMITTED FOR CLARITY.
Figure 11. Four-Quadrant Multiplying Application Circuit
REV. 0
-15-
AD5544/AD5554
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
28-Lead SSOP (RS-28)
0.407 (10.34) 0.397 (10.08)
28
15
1
14
0.078 (1.98) PIN 1 0.068 (1.73)
0.07 (1.79) 0.066 (1.67)
0.008 (0.203) 0.0256 (0.65) 0.002 (0.050) BSC
8 0.015 (0.38) 0 SEATING 0.009 (0.229) 0.010 (0.25) PLANE 0.005 (0.127)
0.03 (0.762) 0.022 (0.558)
-16-
REV. 0
PRINTED IN U.S.A.
C3563-8-4/00 (rev. 0) 00943
0.311 (7.9) 0.301 (7.64)
0.212 (5.38) 0.205 (5.21)

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