View LTC6930CMS8-819PBF_6666842.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

ltc6930-x.xx 1 6930fb C0.10 0.10 6930 ta01b C0.05 0.05 0 frequency error (%) 70 60 40 20 50 30 10 units 0 t a = 25c v + = 3v div = 0 1045 units typical application features applications description 32.768khz to 8.192mhz precision power oscillators the ltc ? 6930 series is a family of very low power precision silicon oscillators with a frequency error less than 0.09%. for each oscillator, the user can select one of 8 frequen- cies between 32.768khz and 8.192mhz. based on a ? xed master oscillator frequency, internal frequency dividers between 1 and 128 provide the 8 different frequencies. the ltc6930 requires no external components other than power supply bypass capacitors. requiring only a single 1.7v to 5.5v supply enables operation from a single li-ion cell or 2 aa alkaline cells. the ltc6930 features a proprietary control architecture that allows for ultralow power operation while maintaining industry leading accuracy and jitter speci? cations. the exceptionally fast start-up time, combined with the low power consumption, is ideal for battery operated applica- tions with frequent power-up cycles. any frequency from 32.768khz to 8.192mhz can be pro- vided by the factory. minimum order sizes apply for custom frequencies. please consult ltc marketing for details. 4mhz micropower clock generator n frequency error <0.09% max at 25c n start-up time <110s at all frequencies n 1.7v to 5.5v single supply operation n 105a typical supply current at 32khz, v + = 3v n 490a typical supply current at 8mhz, v + = 3v n typical rms period jitter <0.15% at v + = 3v n no external components to set frequency n 5 options cover 32.768khz to 8.192mhz: ltc6930-4.19: 4.194304mhz n ltc6930-5.00: 5.000000mhz n ltc6930-7.37: 7.373800mhz n ltc6930-8.00: 8.000000mhz n ltc6930-8.19: 8.192000mhz n where n = 1, 2, 4, 8, 16, 32, 64, 128 (n determined by state of diva, divb, divc pins) n C40c to 125c operating temperature range n tiny 2mm 3mm dfn or ms8 package n digitally controlled oscillator n microprocessor clock n power supply clock n portable and battery operated devices typical frequency error distribution 4mhz 0.1f 6930 ta01a v + = 1.7v to 5.5v i s = 325a at 3v dc v + gnd gnd out divb diva divc v + ltc6930-8.00 l , lt, ltc, ltm, linear technology and the linear logo are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. protected by u.s. patents, including 6342817, 6614313.
ltc6930-x.xx 2 6930fb absolute maximum ratings total supply voltage (v + to gnd) ............................................. C0.3v to 6v any input pin to gnd (div pins) ......................................C0.3v to v + + 0.3v operating temperature range (note 2) ltc6930c ............................................ C40c to 85c ltc6930i.............................................. C40c to 85c ltc6930h .......................................... C40c to 125c (note 1) top view v + out gnd divc v + gnd diva divb dcb package 8-lead (2mm s 3mm) plastic dfn 9 3 4 2 1 6 5 7 8 t jmax = 125c, ja = 64c/w exposed pad (pin 9) must be soldered to gnd 1 2 3 4 v + gnd diva divb 8 7 6 5 v + out gnd divc top view ms8 package 8-lead plastic msop t jmax = 150c, ja = 300c/w (single-layer board) pin configuration speci? ed temperature range (note 3) ltc6930c ................................................ 0c to 70c ltc6930i.............................................. C40c to 85c ltc6930h .......................................... C40c to 125c storage temperature range ................... C65c to 150c lead temperature (soldering, 10 sec) .................. 300c order information lead free finish tape and reel (mini) tape and reel part marking* package description temperature range ltc6930cdcb-4.19#trmpbf ltc6930cdcb-4.19#trpbf lckt 8-lead (2mm 3mm) plastic dfn 0c to 70c ltc6930idcb-4.19#trmpbf ltc6930idcb-4.19#trpbf lckt 8-lead (2mm 3mm) plastic dfn C40c to 85c ltc6930hdcb-4.19#trmpbf ltc6930hdcb-4.19#trpbf lckt 8-lead (2mm 3mm) plastic dfn C40c to 125c ltc6930cdcb-5.00#trmpbf ltc6930cdcb-5.00#trpbf lckv 8-lead (2mm 3mm) plastic dfn 0c to 70c ltc6930idcb-5.00#trmpbf ltc6930idcb-5.00#trpbf lckv 8-lead (2mm 3mm) plastic dfn C40c to 85c ltc6930hdcb-5.00#trmpbf ltc6930hdcb-5.00#trpbf lckv 8-lead (2mm 3mm) plastic dfn C40c to 125c ltc6930cdcb-7.37#trmpbf ltc6930cdcb-7.37#trpbf lckw 8-lead (2mm 3mm) plastic dfn 0c to 70c ltc6930idcb-7.37#trmpbf ltc6930idcb-7.37#trpbf lckw 8-lead (2mm 3mm) plastic dfn C40c to 85c ltc6930hdcb-7.37#trmpbf ltc6930hdcb-7.37#trpbf lckw 8-lead (2mm 3mm) plastic dfn C40c to 125c ltc6930cdcb-8.00#trmpbf ltc6930cdcb-8.00#trpbf lckx 8-lead (2mm 3mm) plastic dfn 0c to 70c ltc6930idcb-8.00#trmpbf ltc6930idcb-8.00#trpbf lckx 8-lead (2mm 3mm) plastic dfn C40c to 85c ltc6930hdcb-8.00#trmpbf ltc6930hdcb-8.00#trpbf lckx 8-lead (2mm 3mm) plastic dfn C40c to 125c ltc6930cdcb-8.19#trmpbf ltc6930cdcb-8.19#trpbf lcky 8-lead (2mm 3mm) plastic dfn 0c to 70c ltc6930idcb-8.19#trmpbf ltc6930idcb-8.19#trpbf lcky 8-lead (2mm 3mm) plastic dfn C40c to 85c ltc6930hdcb-8.19#trmpbf ltc6930hdcb-8.19#trpbf lcky 8-lead (2mm 3mm) plastic dfn C40c to 125c trm = 500 pieces.
ltc6930-x.xx 3 6930fb ac electrical characteristics the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. unless otherwise noted, speci? cations apply over the full range of operating supply voltage and frequency output: v + = 1.7v to 5.5v and all div settings with c load = 5pf, r load = . symbol parameter conditions min typ max units ? initial frequency accuracy diva = divb = divc = 0, t a = 25c, v + = 3v 0.08 0.09 % f frequency accuracy (note 4) v + = 3v C 3.6v ltc6930c ltc6930i ltc6930h l l l 0.1 0.1 0.1 0.45 0.65 1 % % % v + = 2v C 3.6v ltc6930c ltc6930i ltc6930h l l l 0.1 0.1 0.1 0.52 0.65 1.1 % % % v + = 1.7v C 5.5v ltc6930c ltc6930i ltc6930h l l l 0.1 0.1 0.1 0.8 0.95 1.3 % % % f/ t frequency drift over temperature ms8 package dcb package l l 0.0001 0.001 %/c %/c f/ v frequency drift over supply l 0.07 %/v long-term frequency stability (note 5) l 30 ppm/ khr order information lead free finish tape and reel part marking* package description temperature range ltc6930ims8-4.19#pbf ltc6930ims8-4.19#trpbf ltckz 8-lead plastic msop C40c to 85c ltc6930hms8-4.19#pbf ltc6930hms8-4.19#trpbf ltckz 8-lead plastic msop C40c to 125c ltc6930cms8-5.00#pbf ltc6930cms8-5.00#trpbf ltclb 8-lead plastic msop 0c to 70c ltc6930ims8-5.00#pbf ltc6930ims8-5.00#trpbf ltclb 8-lead plastic msop C40c to 85c ltc6930hms8-5.00#pbf ltc6930hms8-5.00#trpbf ltclb 8-lead plastic msop C40c to 125c ltc6930cms8-7.37#pbf ltc6930cms8-7.37#trpbf ltclc 8-lead plastic msop 0c to 70c ltc6930ims8-7.37#pbf ltc6930ims8-7.37#trpbf ltclc 8-lead plastic msop C40c to 85c ltc6930hms8-7.37#pbf ltc6930hms8-7.37#trpbf ltclc 8-lead plastic msop C40c to 125c ltc6930cms8-8.00#pbf ltc6930cms8-8.00#trpbf ltcld 8-lead plastic msop 0c to 70c ltc6930ims8-8.00#pbf ltc6930ims8-8.00#trpbf ltcld 8-lead plastic msop C40c to 85c ltc6930hms8-8.00#pbf ltc6930hms8-8.00#trpbf ltcld 8-lead plastic msop C40c to 125c ltc6930cms8-8.19#pbf ltc6930cms8-8.19#trpbf ltclf 8-lead plastic msop 0c to 70c ltc6930ims8-8.19#pbf ltc6930ims8-8.19#trpbf ltclf 8-lead plastic msop C40c to 85c ltc6930hms8-8.19#pbf ltc6930hms8-8.19#trpbf ltclf 8-lead plastic msop C40c to 125c *temperature grades are identi? ed by a label on the shipping container. consult ltc marketing for parts speci? ed with wider operating temperature ranges. consult ltc marketing for information on lead based ? nish parts. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel speci? cations, go to: http://www.linear.com/tapeandreel/
ltc6930-x.xx 4 6930fb the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. unless otherwise noted, speci? cations apply over the full range of operating supply voltage and frequency output: v + = 1.7v to 5.5v and all div settings with c load = 5pf, r load = . dc electrical characteristics symbol parameter conditions min typ max units v s supply voltage applied between v + and gnd l 1.7 5.5 v i s,dc v + combined supply current ltc6930-4.19 diva = divb = divc = 0, v + = 1.7v diva = divb = divc = 0, v + = 3v diva = divb = divc = 0, v + = 5.5v diva = divb = divc = 1, v + = 1.7v diva = divb = divc = 1, v + = 3v diva = divb = divc = 1, v + = 5.5v l l l l l l 170 260 490 80 105 130 290 420 750 160 190 355 a a a a a a ltc6930-5.00 diva = divb = divc = 0, v + = 1.7v diva = divb = divc = 0, v + = 3v diva = divb = divc = 0, v + = 5.5v diva = divb = divc = 1, v + = 1.7v diva = divb = divc = 1, v + = 3v diva = divb = divc = 1, v + = 5.5v l l l l l l 201 307 579 95 124 154 430 570 960 176 212 375 a a a a a a i s,dc v + combined supply current ltc6930-7.37 diva = divb = divc = 0, v + = 1.7v diva = divb = divc = 0, v + = 3v diva = divb = divc = 0, v + = 5.5v diva = divb = divc = 1, v + = 1.7v diva = divb = divc = 1, v + = 3v diva = divb = divc = 1, v + = 5.5v l l l l l l 296 453 853 139 183 226 480 660 1310 220 273 440 a a a a a a ltc6930-8.00 diva = divb = divc = 0, v + = 1.7v diva = divb = divc = 0, v + = 3v diva = divb = divc = 0, v + = 5.5v diva = divb = divc = 1, v + = 1.7v diva = divb = divc = 1, v + = 3v diva = divb = divc = 1, v + = 5.5v l l l l l l 321 491 926 151 198 246 520 740 1380 240 295 475 a a a a a a ltc6930-8.19 diva = divb = divc = 0, v + = 1.7v diva = divb = divc = 0, v + = 3v diva = divb = divc = 0, v + = 5.5v diva = divb = divc = 1, v + = 1.7v diva = divb = divc = 1, v + = 3v diva = divb = divc = 1, v + = 5.5v l l l l l l 310 500 880 150 190 210 490 760 1400 270 325 540 a a a a a a v ih minimum high level input voltage, all digital input pins l 1.25 1.4 v ac electrical characteristics the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. unless otherwise noted, speci? cations apply over the full range of operating supply voltage and frequency output: v + = 1.7v to 5.5v and all div settings with c load = 5pf, r load = . symbol parameter conditions min typ max units rms period jitter diva = divb = divc = 0, v + = 3v ltc6930-4.19 (4.194304mhz) ltc6930-5.00 (5.000000mhz) ltc6930-7.37 (7.372800mhz) ltc6930-8.00 (8.000000mhz) ltc6930-8.19 (8.192000mhz) 320 1.7 225 1.2 180 0.97 130 0.8 130 0.8 ps rms ns p-p ps rms ns p-p ps rms ns p-p ps rms ns p-p ps rms ns p-p
ltc6930-x.xx 5 6930fb the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. unless otherwise noted, speci? cations apply over the full range of operating supply voltage and frequency output: v + = 1.7v to 5.5v and f out = 32.768khz to 8.192mhz with c load = 5pf, r load = . timing characteristics note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: ltc6930c is guaranteed functional over the operating range of C40c to 85c. note 3: the ltc6930c is guaranteed to meet speci? ed performance from 0c to 70c. the ltc6930c is designed, characterized and expected to meet speci? ed performance from C40c to 85c but is not tested or qa sampled at these temperatures. the ltc6930i is guaranteed to meet speci? ed performance from C40c to 85c. the ltc6930h is guaranteed to meet speci? ed performance from C40c to 125c. note 4: frequency accuracy and frequency drift are de? ned as deviation from the nominal frequency or the nominal frequency divided by the integer set through the div pins for each part. the nominal frequency for the ltc6930 family of parts are de? ned as follows: ltc6930-4.19 f nom = 4.194304mhz ltc6930-5.00 f nom = 5.000000mhz ltc6930-7.37 f nom = 7.372800mhz ltc6930-8.00 f nom = 8.000000mhz ltc6930-8.19 f nom = 8.192000mhz note 5: long-term drift of silicon oscillators is primarily due to the movement of ions and impurities within the silicon and is tested at 30c under otherwise nominal operating conditions. long-term drift is speci? ed as ppm/ khr due to the typically non-linear nature of the drift. to calculate drift for a set time period, translate that time into thousands of hours, take the square root and multiply by the typical drift number. for instance, a year is 8.77khr and would yield a drift of 89ppm at 30ppm/ khr . drift without power applied to the device may be approximated as 1/10th of the drift with power, or 3ppm/ khr for a 30ppm/ khr device. symbol parameter conditions min typ max units t rf output rise/fall time (10% to 90%) v + = 3v 3 ns dcy duty cycle diva = divb = divc = 0; v + = 2v to 5.5v diva = divb = divc = 0 diva or divb or divc 0 l l l 35 35 48 50 50 50 65 70 52 % % % d div div to f out delay edge of div signal to 1st accurate output cycle 1 cycle d pon power on delay v + > 1.7v to 1st accurate output cycle l 110 s the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. unless otherwise noted, speci? cations apply over the full range of operating supply voltage and frequency output: v + = 1.7v to 5.5v and all div settings with c load = 5pf, r load = . dc electrical characteristics symbol parameter conditions min typ max units v il maximum low level input voltage, all digital input pins l 0.7 1.25 v i in digital input leakage current, all digital input pins 0 < v in < v + l 1 a r out output resistance out pin, v + = 3v 40 v oh high level output voltage diva = divb = divc = 0, no load v + = 5.5v v + = 3v v + = 2v v + = 1.7v l l l 5.4 2.9 1.8 5.5 3 2 1.7 v v v v diva = divb = divc = 0, 1k load to gnd v + = 5.5v v + = 3v v + = 2v v + = 1.7v l l l 5 2.6 1.5 5.2 2.7 1.6 1.5 v v v v v ol low level output voltage diva = divb = divc = 0, no load v + = 5.5v v + = 3v v + = 2v v + = 1.7v l l l 0 0 0 0 0.1 0.1 0.1 v v v v diva = divb = divc = 0, 1k load to v + v + = 5.5v v + = 3v v + = 2v v + = 1.7v l l l 0.3 0.3 0.3 0.3 0.7 0.5 0.35 v v v v
ltc6930-x.xx 6 6930fb 6930 g09 40ns/div ltc6930-8.00 c load = 12pf 0.45v/div 6930 g08 400khz/div 10db/div temperature (c) C45 power supply current (a) 4216 g07 5 55 105 700 600 100 200 400 300 500 0 3v, 8.192mhz 1.7v, 32khz c load = 5pf 3v, 4.19mhz load capacitance (pf) 0 supply current (a) 4216 g05 10 20 30 40 50 60 2000 1000 800 600 200 400 1800 1600 1200 1400 0 ltc6930-8.19 div = 1 div = 2 div = 4 div = 8 div = 16 div = 32 div = 64 div = 128 v + = 3v t a = 25c temperature (c) C45 frequency error (%) 115 125 4216 g02 C25 C5 15 35 55 75 95 0.60 0.40 0.20 0 C0.20 C0.40 C0.60 v + = 3v supply voltage (v) 1.7 supply current (a) 4216 g06 2.2 2.7 3.2 3.7 4.2 4.7 5.2 1000 900 800 600 700 100 200 400 300 500 0 8.192mhz divide = 1 t a = 25c 4.194mhz div setting (log) 1 10 100 supply current (a) 600 8.192mhz, 3v 4.194mhz, 1.7v 500 400 300 200 100 0 6930 g04 4.194mhz, 3v 8.192mhz, 1.7v t a = 25c supply voltage (v) 1.7 frequency error (%, normalized to 3v) 4216 g01 2.7 3.7 4.7 0.25 0.20 0.15 0.05 0.10 C0.20 C0.15 C0.05 C0.10 0 C0.25 8.19mhz t a = 25c 4.19mhz temperature (c) C45 frequency error (%) 115 125 4216 g03 C25 C5 15 35 55 75 95 0.60 0.40 0.20 0 C0.20 C0.40 C0.60 v + = 3v typical performance characteristics typical supply current vs div setting typical supply current vs load capacitance typical supply current vs supply voltage typical supply current vs temperature typical output spectrum, 8mhz typical output waveform, 8mhz typical frequency error vs supply voltage frequency error vs temperature, ms8 package frequency error vs temperature, dfn package
ltc6930-x.xx 7 6930fb period error (ps) C450 samples 4216 g11 C300 C150 0 150 450 300 400 300 100 200 0 ltc6930-8.19 v + = 3v t a = 25c divide = 1 time (hours) 0 delta frequency (ppm) 4216 g17 500 1000 1500 2000 3000 2500 500 400 300 100 200 C400 C300 C100 C200 0 C500 25 parts shown t a = 30c 6930 g18 400ns/div time since power applied (s) 0 frequency error (%) 4216 g16 50 100 150 200 10 5 C10 C5 C20 C15 C25 0 C30 supply voltage (v) 1.7 output rise/fall time (ns) 4216 g13 2.2 2.7 3.2 3.7 4.2 4.7 5.2 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 fall time rise time c load = 5pf t a = 25c supply voltage (v) 1.7 output resistance () 4216 g14 2.2 2.7 3.2 3.7 4.2 4.7 5.2 100 90 80 60 70 10 20 40 30 50 0 t a = 25c div setting (log) 1 10 100 jitter (% rms) 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0 6930 g12 8.192mhz 4.194mhz v + = 3v t a = 25c supply voltage (v) 1.7 jitter (% rms) 4216 g10 2.2 2.7 3.2 3.7 4.2 4.7 5.2 0.30 0.25 0.20 0.15 0.10 0.05 0 8.192mhz 4.194mhz t a = 25c typical performance characteristics typical output rise/fall time vs supply typical output resistance vs supply voltage typical output duty cycle vs supply and divide ratio typical frequency settling from power-up typical frequency error vs time (long-term drift) typical output waveform at div pin change typical jitter vs supply in divide by 1 mode typical period jitter histogram typical jitter vs divider setting supply voltage (v) 1.7 duty cycle (%) 4216 g15 2.2 2.7 3.2 3.7 4.2 4.7 5.2 60 58 56 52 54 42 44 48 46 50 40 4mhz, divide by 1 divide by >1 8mhz, divide by 1
ltc6930-x.xx 8 6930fb v + (pins 1, 8): positive supply pins. each supply pin should be bypassed directly to the neighboring gnd pin with a 0.1f ceramic capacitor, and must be externally connected to the other v + pin (see recommended layout). gnd (pins 2, 6): ground pins. each should be connected to a low inductance ground plane and must be connected to the other gnd pin and on the dfn package, pin 9. diva, divb, divc (pins 3, 4, 5): output prescaler. se- lects divide ratio of master oscillator frequency used to generate the output. see frequency setting table 1 for function. these are standard cmos logic inputs with a typical threshold of 1.25v out (pin 7): oscillator output. drives up to 50pf capaci- tive or 1k resistive load (refer to supply current vs load capacitance in typical performance characteristics sec- tion). typical series resistance is less than 80 at 1.7v and less than 40 at 3v supply. the output trace should be isolated as much as possible from pin 1 and pin 2. the out pin is held low during start-up, and remains free from glitches and runt pulses during div pin switching. exposed pad (pin 9, dfn only): the exposed pad must be soldered to a pcb plane connected to gnd. applications information theory of operation the ltc6930 is an entirely self contained all silicon oscil- lator which consists of a master oscillator, a control loop and an output frequency divider. the master oscillator operates between 4.2mhz and 8.2mhz and is factory programmed. the master oscillator frequency is accurately maintained over temperature and environmental extremes by a proprietary switched capacitor feedback loop. each ltc6930 oscillator has an output frequency divider which is controlled via the diva, divb and divc inputs. the divider divides the master frequency by 2 n , where n is an integer from 0 to 7 (divider ranges from 1 to 128). see table 1 for the full range of frequencies covered by the ltc6930 family. the presence of two sets of supply pins and careful internal layout reduce interference between the oscillator output and the control loop. this allows the ltc6930 to provide a clean output frequency with very little deterministic jitter, even in cases of heavy output loading and noisy operating environments. the supply voltage of the ltc6930 is internally regulated to maintain a very low frequency drift over supply. output driver and loading the output of the ltc6930 is a low series resistance 40 cmos driver with controlled rise/fall times to limit rf interference and power supply spikes generated by the output while preserving the ability to drive low impedance loads. especially at high frequencies, the capacitive loading of the output of the ltc6930 may cause the majority of the power supply dissipation of the part. the ltc6930 supply current is speci? ed at an output load of 5pf, which is equivalent to two standard hc logic inputs. the portion of the power supply current needed to drive a capacitive load may be calculated as: icvf supply load swing osc = ?? where c load is the 5pf load capacitance, v swing is the voltage swing, in this case up to 5.5v, and f osc is the frequency of the oscillator output. driving a 5.5v swing into a 5pf load at 8mhz takes an average of 220a. to calculate the portion of the supply current needed for a 50pf load, simply substitute 50pf for c load in the same equation: 50pf ? 5.5v ? 8mhz = 2.2ma the majority of this power is expended during the rise and fall time of the output signal, not while it is in a steady pin functions
ltc6930-x.xx 9 6930fb months 0 drift (%) 40 0.045 0.040 0.035 0.030 0.025 0.020 0.015 0.010 0.005 0 6930 f02 20 80 60 10ppm/ khr 30ppm/ khr 60ppm/ khr applications information state. the 2ns rise and fall times of the ltc6930 mean that the instantaneous power supply current required during the rise and fall portions of the waveform is much greater than the average. the instantaneous power supply current may be calculated by a similar formula: icv t peak load swing rf = ?? 1 where t rf is the rise/fall time of the signal. in this case, 14ma spikes are generated by driving 5.5v into a 5pf load. power is supplied to the output driver of the ltc6930 from the v + and gnd pins on each side of the output pin (pins 6 and 8). allowances must be made in the design to provide for output load related supply current spikes, especially in high accuracy applications. a 0.1f ceramic capacitor connected between v + and gnd (pins 6 and 8) as close as possible to the device will decouple the rest of the circuit from spikes caused by powering a capacitive output load of up to 50pf. see figure 1. start-up time the start-up time of the ltc6930 is typically 50s from the time that valid power is applied to the ? rst output pulse. the output is held low for the ? rst 50s to prevent any glitches, runt pulses, or invalid frequency output during start-up. long-term drift long-term stability of silicon oscillators is speci? ed in ppm/ khr , which is typical of other silicon devices such as operational ampli? ers and voltage references. because drift in silicon-based oscillators is generated primarily by movement of ions in the silicon, most of the drift is ac- complished early in the life of the device and the drift can be expected to level off in the long term. the ppm/ khr unit models this time variant decay. crystal oscillators are often speci? ed with drift measured in ppm/year be- cause their drift mechanism is different. a comparison of various drift rates over a ? ve year time period is shown in figure 2. when calculating the amount of drift to be expected, it is important to consider the entire time in the calculation, because the relationship to time is not linear. the drift for 5 years is not 5 times the drift for one year. a sample figure 2. 5 year drift at various rates switching the div pins the ltc6930 is designed to quickly and cleanly respond to the digital inputs. the output will respond to the div pins within a single clock cycle without introducing any sliver or runt pulses. 6930 f01 out v + c2 0.1f c1 0.1f gnd gnd figure 1. recommended layout
ltc6930-x.xx 10 6930fb applications information table 1. frequency setting and available frequencies 1 2 4 8 16 32 64 128 div pin settings [divc][divb][diva] 000 001 010 011 100 101 110 111 ltc6930-4.19 4.194304mhz 2.097152mhz 1.048576mhz 524.288khz 262.144khz 131.072khz 65.536khz 32.768khz ltc6930-5.00 5.000mhz 2.500mhz 1.250mhz 625.0khz 312.5khz 156.25khz 78.125khz 39.0625khz ltc6930-7.37 7.3728mhz 3.6864mhz 1.8432mhz 921.6khz 460.8khz 230.4khz 115.2khz 57.6khz ltc6930-8.00 8.000mhz 4.000mhz 2.000mhz 1000khz 500.0khz 250.0khz 125.0khz 62.5khz ltc6930-8.19 8.192mhz 4.096mhz 2.048mhz 1024khz 512.0khz 256.0khz 128.0khz 64.0khz calculation for drift over 5 years at 30ppm/ khr is as follows: 5 years ? 365.25 days/year ? 24 hours/day = 43,830 hours = 43.830khr 43.830khr = 6.62 khr 6.62 khr ? 30ppm/ khr = 0.0198% over 5 years. drift calculations assume that the part is in continuous operation during the entire time period of the calculation. the movement of ions which results in drift is usually aided by electric ? elds in the operating parts, and the typical drift spec applies while the part is powered up. conservative calculations would use a tenth of the drift speci? cation for time when power is not applied to the part. setting the frequency the output frequency of the ltc6930 is chosen from the values in table 1 and set using the div pins, as noted in the table. master oscillator frequency is preset in the factory, and the div pins select an internal binary divider of up to 128. for example, if the desired oscillator output frequency is 2.5mhz, ? nding 2.5mhz in table 1 shows that the ltc6930-5.00 should be ordered, having a master oscil- lator frequency of 5mhz, and a div value of [001] should be used. this would equate to grounding divc and divb, while connecting diva to the positive supply. frequencies other than those shown in table 1 may be requested.
ltc6930-x.xx 11 6930fb information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. package description 3.00 0.10 (2 sides) 2.00 0.10 (2 sides) note: 1. drawing is not a jedec package outline 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package 0.40 0.10 bottom view?exposed pad 0.75 0.05 r = 0.115 typ r = 0.05 typ 1.35 ref 1 4 8 5 pin 1 bar top mark (see note 6) 0.200 ref 0.00 ? 0.05 (dcb8) dfn 0106 rev a 0.23 0.05 0.45 bsc pin 1 notch r = 0.20 or 0.25 45 chamfer 0.25 0.05 1.35 ref recommended solder pad pitch and dimensions apply solder mask to areas that are not soldered 2.10 0.05 0.70 0.05 3.50 0.05 package outline 0.45 bsc 1.35 0.10 1.35 0.05 1.65 0.10 1.65 0.05 msop (ms8) 0307 rev f 0.53 0.152 (.021 .006) seating plane note: 1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.18 (.007) 0.254 (.010) 1.10 (.043) max 0.22 ? 0.38 (.009 ? .015) typ 0.1016 0.0508 (.004 .002) 0.86 (.034) ref 0.65 (.0256) bsc 0 ? 6 typ detail ?a? detail ?a? gauge plane 12 3 4 4.90 0.152 (.193 .006) 8 7 6 5 3.00 0.102 (.118 .004) (note 3) 3.00 0.102 (.118 .004) (note 4) 0.52 (.0205) ref 5.23 (.206) min 3.20 ? 3.45 (.126 ? .136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.42 0.038 (.0165 .0015) typ 0.65 (.0256) bsc ms8 package 8-lead plastic msop (reference ltc dwg # 05-08-1660 rev f) dcb package 8-lead plastic dfn (2mm 3mm) (reference ltc dwg # 05-08-1718 rev a)
ltc6930-x.xx 12 6930fb linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2008 lt 0809 rev b ? printed in usa related parts typical application part number description comments ltc1799 1khz to 33mhz thinsot oscillator, resistor set wide frequency range ltc6900 1khz to 20mhz thinsot oscillator, resistor set low power, wide frequency range ltc6902 multiphase oscillator with spread spectrum modulation 2-, 3- or 4-phase outputs ltc6903/ltc6904 1khz to 68mhz serial port programmable oscillator 0.1% frequency resolution, i 2 c or spi interface ltc6905 17mhz to 170mhz thinsot oscillator, resistor set high frequency, 100s start-up, 7ps rms jitter ltc6905-xxx fixed frequency thinsot oscillator family, up to 133mhz no trim components required ltc6906 micropower 10khz to 1mhz thinsot oscillator, resistor set 12a supply current at 100khz, 0.65% frequency accuracy ltc6907 micropower 40khz to 4mhz thinsot oscillator, resistor set 36a supply current at 400khz, 0.65% frequency accuracy ltc6908 multiphase oscillator with spread spectrum modulation 2 outputs shifted by either 180 or 90 5v 0.1f 18 27 36 45 v out1 v in1 5v 1f 2k 3.48k 5v 6930 ta02 ltc1569-7 in + in C gnd v C out v + r x div/clk 0.1f 18 27 36 45 v out2 v in2 5v 1f 2k 3.48k 5v ltc1569-7 in + in C gnd v C out v + r x div/clk 0.1f 18 27 36 45 0.1f ltc6930-8.192 v + gnd diva divb diva divb divc v + out gnd divc frequency (khz) 1 gain (db) 0 C20 C40 C60 C80 C100 10 100 1000 32khz f cutoff = 8khz 128khz f osc dual, matched, digitally programmable, lowpass filter, 2khz to 256khz amplitude response divc, divb, diva 000 001 010 011 100 101 110 111 f cutoff 256khz 128khz 64khz 32khz 16khz 8khz 4khz 2khz

▲Up To Search▲

Price & Availability of LTC6930CMS8-819PBF

	To Download LTC6930CMS8-819PBF Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .