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1 ltc1591/ltc1597 14-bit and 16-bit parallel low glitch multiplying dacs with 4-quadrant resistors descriptio n u the ltc ? 1591/ltc1597 are pin compatible, parallel input 14-bit and 16-bit multiplying current output dacs that oper- ate from a single 5v supply. inl and dnl are accurate to 1lsb over the industrial temperature range in both 2- and 4- quadrant multiplying modes. true 16-bit 4-quadrant multi- plication is achieved with on-chip 4-quadrant multiplication resistors. these dacs include an internal deglitcher circuit that reduces the glitch impulse to less than 2nv-s (typ). the asynchronous clr pin resets the ltc1591/ltc1597 to zero scale and ltc1591-1/ltc1597-1 to midscale. the ltc1591/ltc1597 are available in 28-pin ssop and pdip packages and are specified over the industrial tempera- ture range. for serial interface 16-bit current output dacs refer to the ltc1595/ltc1596 data sheet. n process control and industrial automation n direct digital waveform generation n software-controlled gain adjustment n automatic test equipment applicatio n s u n true 16-bit performance over industrial temperature range n dnl and inl: 1lsb max n on-chip 4-quadrant resistors allow precise 0v to 10v, 0v to C 10v or 10v outputs n pin compatible 14- and 16-bit parts n asynchronous clear pin ltc1591/ltc1597: reset to zero scale ltc1591-1/ltc1597-1: reset to midscale n glitch impulse < 2nv-s n 28-lead ssop package n low power consumption: 10 m w typ n power-on reset features , ltc and lt are registered trademarks of linear technology corporation. typical applicatio n u ltc1591/ltc1591-1 integral nonlinearity ltc1597/ltc1597-1 integral nonlinearity digital input code 0 integral nonlinearity (lsb) 1.0 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1.0 16384 32768 1591/97 ta03 49152 65535 v ref = 10v v out = 10v bipolar digital input code 0 integral nonlinearity (lsb) 1.0 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 1.0 4096 8192 1591/97 ta02 12288 16383 v ref = 10v v out = 10v bipolar 16-bit, 4-quadrant multiplying dac with a minimum of external components v cc ltc1597-1 r fb r fb r ofs r ofs 5v ld ld 32 98 28 23 15pf 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 15pf v out = ? ref to v ref 1591/97 ta01 agnd dgnd + lt 1468 wr 10 to 21, 24 to 27 wr clr clr v ref + lt1468 16-bit dac r1 r2 16 data inputs
2 ltc1591/ltc1597 absolute m axi m u m ratings w ww u v cc to agnd ............................................... C 0.5v to 7v v cc to dgnd .............................................. C 0.5v to 7v agnd to dgnd ............................................. v cc + 0.5v dgnd to agnd ............................................. v cc + 0.5v ref, r ofs , r fb , r1, r com to agnd, dgnd .......... 25v digital inputs to dgnd ............... C 0.5v to (v cc + 0.5v) i out1 to agnd ............................ C 0.5v to( v cc + 0.5v) maximum junction temperature .......................... 125 c operating temperature range ltc1591c/ltc1591-1c ltc1597c/ltc1597-1c .......................... 0 c to 70 c ltc1591i/LTC1591-1I ltc1597i/ltc1597-1i ....................... C 40 c to 85 c storage temperature range ................ C 65 c to 150 c lead temperature (soldering, 10 sec)................. 300 c (note 1) package/order i n for m atio n w u u order part number order part number ltc1591cg ltc1591cn ltc1591ig ltc1591in ltc1591-1cg ltc1591-1cn LTC1591-1Ig LTC1591-1In ltc1597acg ltc1597acn ltc1597bcg ltc1597bcn ltc1597-1acg ltc1597-1acn ltc1597-1bcg ltc1597-1bcn ltc1597aig ltc1597ain ltc1597big ltc1597bin ltc1597-1aig ltc1597-1ain ltc1597-1big ltc1597-1bin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 top view g package 28-lead plastic ssop n package 28-lead narrow pdip 28 27 26 25 24 23 22 21 20 19 18 17 16 15 clr nc nc d0 d1 v cc dgnd d2 d3 d4 d5 d6 d7 d8 ref r com r1 r ofs r fb i out1 agnd ld wr d13 d12 d11 d10 d9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 top view g package 28-lead plastic ssop n package 28-lead narrow pdip 28 27 26 25 24 23 22 21 20 19 18 17 16 15 clr d0 d1 d2 d3 v cc dgnd d4 d5 d6 d7 d8 d9 d10 ref r com r1 r ofs r fb i out1 agnd ld wr d15 d14 d13 d12 d11 t jmax = 125 c, q ja = 95 c/ w (g) t jmax = 125 c, q ja = 70 c/ w (n) consult factory for military grade parts. t jmax = 125 c, q ja = 95 c/ w (g) t jmax = 125 c, q ja = 70 c/ w (n)
3 ltc1591/ltc1597 electrical characteristics v cc = 5v 10%, v ref = 10v, i out1 = agnd = dgnd = 0v, t a = t min to t max , unless otherwise noted. ltc1591/-1 ltc1597b/-1b ltc1597a/-1a symbol parameter conditions min typ max min typ max min typ max units accuracy resolution l 14 16 16 bits monotonicity l 14 16 16 bits inl integral nonlinearity (note 2) t a = 25 c 1 2 0.25 1 lsb t min to t max l 1 2 0.35 1 lsb dnl differential nonlinearity t a = 25 c 1 1 0.2 1 lsb t min to t max l 1 1 0.2 1 lsb ge gain error unipolar mode (note 3) t a = 25 c 4 16 2 16 lsb t min to t max l 6 24 3 16 lsb bipolar mode (note 3) t a = 25 c 4 16 2 16 lsb t min to t max l 6 24 3 16 lsb gain temperature coefficient (note 4) d gain/ d temperature l 1 2 1 2 1 2 ppm/ c bipolar zero-scale error t a = 25 c 3 10 5 lsb t min to t max l 5 16 8 lsb i lkg out1 leakage current (note 5) t a = 25 c 5 5 5na t min to t max l 15 15 15 na psrr power supply rejection ratio v cc = 5v 10 l 0.1 1 0.4 2 0.4 2 lsb/v v cc = 5v 10%, v ref = 10v, i out1 = agnd = dgnd = 0v, t a = t min to t max , unless otherwise noted. symbol parameter conditions min typ max units reference input r ref dac input resistance (unipolar) (note 6) l 4.5 6 10 k w r1/r2 r1/r2 resistance (bipolar) (notes 6, 13) l 91220 k w r ofs , r fb feedback and offset resistances (note 6) l 91220 k w ac performance (note 4) output current settling time (notes 7, 8) 1 m s midscale glitch impulse (note 12) 2 nv-s digital-to-analog glitch impulse (note 9) 1 nv-s multiplying feedthrough error v ref = 10v, 10khz sine wave 1 mv p-p thd total harmonic distortion (note 10) 108 db output noise voltage density (note 11) 10 nv/ ? hz harmonic distortion unipolar mode (note 14) (digital waveform generation) 2nd harmonic 94 db 3rd harmonic 101 db sfdr 94 db bipolar mode (note 14) 2nd harmonic 94 db 3rd harmonic 101 db sfdr 94 db
4 ltc1591/ltc1597 electrical characteristics v cc = 5v 10%, v ref = 10v, i out1 = agnd = dgnd = 0v, t a = t min to t max , unless otherwise noted. symbol parameter conditions min typ max units analog outputs (note 4) c out output capacitance (note 4) dac register loaded to all 1s: c out1 l 115 130 pf dac register loaded to all 0s: c out1 l 70 80 pf digital inputs v ih digital input high voltage l 2.4 v v il digital input low voltage l 0.8 v i in digital input current l 0.001 1 m a c in digital input capacitance (note 4) v in = 0v l 8pf timing characteristics t ds data to wr setup time l 60 20 ns t dh data to wr hold time l 0 C12 ns t wr wr pulse width l 60 25 ns t ld ld pulse width l 110 55 ns t clr clear pulse width l 60 40 ns t lwd wr to ld delay time l 0ns power supply v dd supply voltage l 4.5 5 5.5 v i dd supply current digital inputs = 0v or v cc l 10 m a the l denotes specifications that apply over the full operating temperature range. note 1: absolute maximum values are those beyond which the life of a device may be impaired. note 2: 1lsb = 0.006% of full scale = 61ppm of full scale for the ltc1591/ltc1591-1. 1lsb = 0.0015% of full scale = 15.3ppm of full scale for the ltc1597/ltc1597-1. note 3: using internal feedback resistor. note 4: guaranteed by design, not subject to test. note 5: i (out1) with dac register loaded to all 0s. note 6: typical temperature coefficient is 100ppm/ c. note 7: i out1 load = 100 w in parallel with 13pf. note 8: to 0.006% for a full-scale change, measured from the rising edge of ld for the ltc1591/ltc1591-1. to 0.0015% for a full-scale change, measured from the rising edge of ld for the ltc1597/ltc1597-1. note 9: v ref = 0v. dac register contents changed from all 0s to all 1s or all 1s to all 0s. note 10: v ref = 6v rms at 1khz. dac register loaded with all 1s. note 11: calculation from e n = ? 4ktrb where: k = boltzmann constant (j/ k), r = resistance ( w ), t = temperature ( k), b = bandwidth (hz). note 12: midscale transition code: 01 1111 1111 1111 to 10 0000 0000 0000 for the ltc1591/ltc1591-1 and 0111 1111 1111 1111 to 1000 0000 0000 0000 for the ltc1597/ltc1597-1. note 13: r1 and r2 are measured between r1 and r com , ref and r com . note 14: measured using the lt1468 op amp in unipolar mode for i/v converter and lt1468 i/v and lt1001 reference inverter in bipolar mode. sample rate = 50khz, signal frequency = 1khz, v ref = 5v, t a = 25 c.
5 ltc1591/ltc1597 typical perfor a ce characteristics uw unipolar multiplying mode signal-to-(noise + distortion) vs frequency (ltc1591/ltc1597) frequency (hz) ?0 signal/(noise + distortion) (db) ?0 ?0 ?0 10 1k 10k 100k 1591/97 g03 110 100 ?0 ?0 100 v cc = 5v using an lt1468 c feedback = 30pf reference = 6v rms 500khz filter 80khz filter 30khz filter midscale glitch impulse time ( s) 0 output voltage (mv) ?0 0 10 0.6 1.0 1591/97 g01 ?0 ?0 ?0 0.2 0.4 0.8 20 30 40 using an lt1468 c feedback = 30pf v ref = 10v 1nv-s typical full-scale settling waveform gated settling waveform 500 m v/div ld pulse 5v/div 500ns/div 1591/97 g02 using lt1468 op amp c feedback = 20pf 0v to 10v step bipolar multiplying mode signal-to-(noise + distortion) vs frequency, code = all zeros frequency (hz) ?0 signal/(noise + distortion) (db) ?0 ?0 ?0 10 1k 10k 100k 1591/97 g04 110 100 ?0 ?0 100 v cc = 5v using two lt1468s c feedback = 15pf reference = 6v rms 500khz filter 80khz filter 30khz filter bipolar multiplying mode signal-to-(noise + distortion) vs frequency, code = all ones frequency (hz) ?0 signal/(noise + distortion) (db) ?0 ?0 ?0 10 1k 10k 100k 1591/97 g05 110 100 ?0 ?0 100 v cc = 5v using two lt1468s c feedback = 15pf reference = 6v rms 500khz filter 80khz filter 30khz filter supply current vs input voltage intput voltage (v) 0 supply current (ma) 3 4 5 4 1591/97 g06 2 1 0 1 2 3 5 v cc = 5v all digital inputs tied together logic threshold vs supply voltage supply voltage (v) 0 0 logic threshold (v) 0.5 1.0 1.5 2.0 3.0 1 234 1591/97 g07 57 6 2.5
6 ltc1591/ltc1597 typical perfor a ce characteristics uw digital input code 0 1.0 integral nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 4096 8192 1591 g01 0.6 0.6 0.8 0.2 12280 16383 integral nonlinearity (inl) reference voltage (v) ?0 integral nonlinearity (lsb) 0.2 0.6 1.0 6 1591 g03 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 integral nonlinearity vs reference voltage in unipolar mode digital input code 0 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 4096 8192 1591 g02 0.6 0.6 0.8 0.2 12280 16383 differential nonlinearity (dnl) integral nonlinearity vs reference voltage in bipolar mode reference voltage (v) ?0 integral nonlinearity (lsb) 0.2 0.6 1.0 6 1591 g04 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 differential nonlinearity vs reference voltage in unipolar mode reference voltage (v) ?0 differential nonlinearity (lsb) 0.2 0.6 1.0 6 1591 g05 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 (ltc1591) differential nonlinearity vs reference voltage in bipolar mode reference voltage (v) ?0 differential nonlinearity (lsb) 0.2 0.6 1.0 6 1591 g06 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 integral nonlinearity vs supply voltage in unipolar mode supply voltage (v) 0 1.0 integral nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1591 g07 0.6 0.6 0.8 0.2 1 3 6 7 v ref = 10v v ref = 2.5v v ref = 10v v ref = 2.5v integral nonlinearity vs supply voltage in bipolar mode supply voltage (v) 0 1.0 integral nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1591 g08 0.6 0.6 0.8 0.2 1 3 6 7 v ref = 10v v ref = 2.5v v ref = 10v v ref = 2.5v differential nonlinearity vs supply voltage in unipolar mode supply voltage (v) 0 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1591 g09 0.6 0.6 0.8 0.2 1 3 6 7 v ref = 10v v ref = 2.5v v ref = 10v v ref = 2.5v
7 ltc1591/ltc1597 typical perfor a ce characteristics uw (ltc1591) differential nonlinearity vs supply voltage in bipolar mode supply voltage (v) 0 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1591 g10 0.6 0.6 0.8 0.2 1 3 6 7 v ref = 10v v ref = 10v v ref = 2.5v v ref = 2.5v bipolar multiplying mode frequency response vs digital code unipolar multiplying mode frequency response vs digital code bipolar multiplying mode frequency response vs digital code frequency (hz) 100 attenuation (db) ?0 ?0 0 10 1k 10k 10m 1m *dac zero voltage output limited by bipolar zero error to 84db typical (70db max) 100 100k ?0 ?0 d13 and d12 on d13 and d11 on d13 and d10 on d13 and d9 on d13 and d8 on d13 and d7 on d13 and d6 on d13 and d5 on d13 and d4 on d13 and d3 on d13 and d2 on d13 and d1 on d13 and d0 on all bits on 1591 g12 15pf 12pf + + 12pf v ref v out 1 2 34 6 7 22 5 lt1468 lt1468 ltc1591 codes from midscale to full scale d13 on * frequency (hz) 100 attenuation (db) ?0 ?0 0 10 1k 10k 10m 1m 1591g13 100 100k ?0 ?0 *dac zero voltage output limited by bipolar zero error to 84db typical (70db max) 15pf 12pf + + 12pf v ref v out 1 2 34 6 7 22 5 lt1468 lt1468 ltc1591 codes from midscale to zero scale d12 on d12 and d11 on d12 to d10 on d12 to d9 on d12 to d8 on d12 to d7 on d12 to d6 on d12 to d5 on d12 to d4 on d12 to d3 on d12 to d2 on d12 to d1 on d12 to d0 on all bits off d13 on * frequency (hz) 100 attenuation (db) ?0 ?0 0 100 10k 100k 10m 1591g11 120 1k 1m ?0 ?0 all bits off + 30pf 3214 6 7 22 5 lt1468 ltc1591 v out v ref d9 on d8 on d6 on d5 on d4 on d3 on d2 on d1 on d13 on d12 on d11 on d10 on all bits on d7 on d0 on
8 ltc1591/ltc1597 typical perfor a ce characteristics uw integral nonlinearity (inl) integral nonlinearity vs reference voltage in unipolar mode differential nonlinearity (dnl) integral nonlinearity vs reference voltage in bipolar mode differential nonlinearity vs reference voltage in unipolar mode (ltc1597) differential nonlinearity vs reference voltage in bipolar mode integral nonlinearity vs supply voltage in unipolar mode integral nonlinearity vs supply voltage in bipolar mode differential nonlinearity vs supply voltage in unipolar mode digital input code 0 1.0 integral nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 16384 32768 1597 g01 0.6 0.6 0.8 0.2 49152 65535 digital input code 0 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 16384 32768 1597 g02 0.6 0.6 0.8 0.2 49152 65535 reference voltage (v) ?0 integral nonlinearity (lsb) 0.2 0.6 1.0 6 1597 g03 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 reference voltage (v) ?0 integral nonlinearity (lsb) 0.2 0.6 1.0 6 1597 g04 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 reference voltage (v) ?0 differential nonlinearity (lsb) 0.2 0.6 1.0 6 1597 g05 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 reference voltage (v) ?0 differential nonlinearity (lsb) 0.2 0.6 1.0 6 1597 g06 0.2 0.6 0 0.4 0.8 0.4 0.8 1.0 ? ? 2 ? 8 ? 0 4 10 supply voltage (v) 1.0 integral nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1597 g07 0.6 0.6 0.8 0.2 3 6 7 v ref = 10v v ref = 10v v ref = 2.5v v ref = 2.5v supply voltage (v) integral nonlinearity (lsb) 2.0 ?.0 0.5 0 2.0 1.0 2 4 5 1597 g08 ?.5 1.5 0.5 3 6 7 v ref = 10v v ref = 10v v ref = 2.5v v ref = 2.5v supply voltage (v) 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1597 g09 0.6 0.6 0.8 0.2 3 6 7 v ref = 10v v ref = 2.5v v ref = 10v v ref = 2.5v
9 ltc1591/ltc1597 typical perfor a ce characteristics uw (ltc1597) differential nonlinearity vs supply voltage in bipolar mode supply voltage (v) 1.0 differential nonlinearity (lsb) 0.8 0.4 0.2 0 1.0 0.4 2 4 5 1597 g10 0.6 0.6 0.8 0.2 3 6 7 v ref = 10v v ref = 10v v ref = 2.5v v ref = 2.5v frequency (hz) 100 120 attenuation (db) ?0 ?0 0 100 10k 100k 10m 1597g11 1k 1m ?0 ?0 d15 on d14 on d13 on d12 on all bits on d9 on d1 on d0 on + 30pf 3214 6 7 22 5 lt1468 ltc1597 v out v ref d11 on d10 on d8 on d7 on d6 on d5 on d4 on d3 on d2 on all bits off unipolar multiplying mode frequency response vs digital code frequency (hz) 100 attenuation (db) ?0 ?0 0 10 *dac zero voltage output limited by bipolar zero error to 96db typical (?8db max, a grade) 1k 10k 10m 1m 1597 g12 100 100k ?0 ?0 d15 and d14 on d15 and d13 on d15 and d12 on d15 and d11 on d15 and d10 on d15 and d9 on d15 and d8 on d15 and d7 on d15 and d6 on d15 and d5 on d15 and d4 on d15 and d3 on d15 and d2 on all bits on 15pf 12pf + + 12pf v ref v out 1 2 34 6 7 22 5 lt1468 lt1468 ltc1597 d15 on * d15 and d0 on d15 and d1 on codes from midscale to full scale bipolar multiplying mode frequency response vs digital code bipolar multiplying mode frequency response vs digital code frequency (hz) 100 attenuation (db) ?0 ?0 0 10 1k 10k 10m 1m 1597 g13 100 100k ?0 ?0 d14 on d14 and d13 on d14 to d12 on d14 to d11 on d14 to d10 on d14 to d9 on d14 to d8 on d14 to d7 on d14 to d6 on d14 to d5 on d14 to d4 on d14 to d3 on d14 to d2 on d14 to d1 on all bits off *dac zero voltage output limited by bipolar zero error to 96db typical (?8db max, a grade) 15pf 12pf + + 12pf v ref v out 1 2 34 6 7 22 5 lt1468 lt1468 ltc1597 d14 to d0 on d15 on * codes from midscale to zero scale
10 ltc1591/ltc1597 pi n fu n ctio n s uuu ltc1591 ref (pin 1): reference input and 4-quadrant resistor r2. typically 10v, accepts up to 25v. in 2-quadrant mode this is the reference input. in 4-quadrant mode, this pin is driven by external inverting reference amplifier. r com (pin 2): center tap point of the two 4-quadrant resistors r1 and r2. normally tied to the inverting input of an external amplifier in 4-quadrant operation, otherwise shorted to the ref pin. see figures 1a and 2a. r1 (pin 3): 4-quadrant resistor r1. in 2-quadrant opera- tion short to the ref pin. in 4-quadrant mode tie to r ofs (pin 4). r ofs (pin 4): bipolar offset resistor. typically swings 10v, accepts up to 25v. in 2-quadrant operation tie to r fb . in 4-quadrant operation tie to r1. r fb (pin 5): feedback resistor. normally tied to the output of the current to voltage converter op amp. swings to v ref . v ref is typically 10v. i out1 (pin 6): dac current output. tie to the inverting input of the current to voltage converter op amp. agnd (pin 7): analog ground. tie to ground. ld (pin 8): dac digital input load control input. when ld is taken to a logic high, data is loaded from the input register into the dac register, updating the dac output. wr (pin 9): dac digital write control input. when wr is taken to a logic low, data is loaded from the digital input pins into the 14-bit wide input register. db13 to d2 (pins 10 to 21): digital input data bits. dgnd (pin 22): digital ground. tie to ground. v cc (pin 23): the positive supply input. 4.5v v cc 3 5.5v. requires a bypass capacitor to ground. db1, db0 (pins 24, 25): digital input data bits. nc (pins 26, 27): no connect. clr (pin 28): digital clear control function for the dac. when clr is taken to a logic low, it sets the dac output and all internal registers to zero code for the ltc1591 and midscale code for the ltc1591-1. ltc1597 ref (pin 1): reference input and 4-quadrant resistor r2. typically 10v, accepts up to 25v. in 2-quadrant mode this is the reference input. in 4-quadrant mode, this pin is driven by external inverting reference amplifier. r com (pin 2): center tap point of the two 4-quadrant resistors r1 and r2. normally tied to the inverting input of an external amplifier in 4-quadrant operation, otherwise shorted to the ref pin. see figures 1b and 2b. r1 (pin 3): 4-quadrant resistor r1. in 2-quadrant opera- tion short to the ref pin. in 4-quadrant mode tie to r ofs (pin 4). r ofs (pin 4): bipolar offset resistor. typically swings 10v, accepts up to 25v. in 2-quadrant operation tie to r fb . in 4-quadrant operation tie to r1. r fb (pin 5): feedback resistor. normally tied to the output of the current to voltage converter op amp. swings to v ref . v ref is typically 10v. i out1 (pin 6): dac current output. tie to the inverting input of the current to voltage converter op amp. agnd (pin 7): analog ground. tie to ground. ld (pin 8): dac digital input load control input. when ld is taken to a logic high, data is loaded from the input register into the dac register, updating the dac output. wr (pin 9): dac digital write control input. when wr is taken to a logic low, data is loaded from the digital input pins into the 16-bit wide input register. db15 to d4 (pins 10 to 21): digital input data bits. dgnd (pin 22): digital ground. tie to ground. v cc (pin 23): the positive supply input. 4.5v v cc 3 5.5v. requires a bypass capacitor to ground. db3 to db0 (pins 24 to 27): digital input data bits. clr (pin 28): digital clear control function for the dac. when clr is taken to a logic low, it sets the dac output and all internal registers to zero code for the ltc1597 and midscale code for the ltc1597-1.
11 ltc1591/ltc1597 table 1 control inputs clr wr ld register operation 0 x x reset input and dac register to all 0s for ltc1591/ltc1597 and midscale for ltc1591-1/ltc1597-1 (asynchronous operation) 1 0 0 load input register with all 14/16 data bits 1 1 1 load dac register with the contents of the input register 1 0 1 input and dac register are transparent 1 clk = ld and wr tied together. the 14/16 data bits are loaded into the input register on the falling edge of the clk and then loaded into the dac register on the rising edge of the clk 1 1 0 no register operation truth table block diagra s m w ltc1591 96k 12k 12k 96k 48k 96k 48k 96k decoder d13 (msb) d11 d12 d13 d10 d9 d0 (lsb) load v cc ref r fb i out1 agnd clr 28 dgnd 22 1591 bd dac register 48k 48k 48k 48k 48k 48k 48k 12k 8 23 r1 3 r com 2 1 ld 9 10 d12 11 d2 21 d1 24 d0 25 nc 27 nc 26 wr 7 6 5 r ofs 4 ? 12k wr input register ??? rst rst
12 ltc1591/ltc1597 block diagra s m w ltc1597 96k 12k 12k 96k 48k 96k 48k 96k decoder d15 (msb) d13 d14 d15 d12 d11 d0 (lsb) load v cc ref r fb i out1 agnd clr 28 dgnd 22 1597 bd dac register 48k 48k 48k 48k 48k 48k 48k 12k 8 23 r1 3 r com 2 1 ld 9 10 d14 11 d4 21 d3 24 d2 25 d0 27 d1 26 wr 7 6 5 r ofs 4 ? 12k wr input register ??? rst rst ti i g diagra u w w data ld clr 1591/97td t wr t ds t ld t dh t lwd wr t clr
13 ltc1591/ltc1597 description the ltc1591/ltc1597 are 14-/16-bit multiplying, current output dacs with a full parallel 14-/16-bit digital interface. the devices operate from a single 5v supply and provide both unipolar 0v to C 10v or 0v to 10v and bipolar 10v output ranges from a 10v or C10v reference input. they have three additional precision resistors on chip for bipo- lar operation. refer to the block diagrams regarding the following description. the 14-/16-bit dacs consist of a precision r-2r ladder for the 11/13lsbs. the 3msbs are decoded into seven seg- ments of resistor value r. each of these segments and the r-2r ladder carries an equally weighted current of one eighth of full scale. the feedback resistor r fb and 4-quadrant resistor r ofs have a value of r/4. 4-quadrant resistors r1 and r2 have a magnitude of r/4. r1 and r2 together with an external op amp (see figure 2) inverts the reference input voltage and applies it to the 14-/16-bit dac input ref, in 4-quadrant operation. the ref pin presents a constant input impedance of r/8 in unipolar mode and r/12 in bipolar mode. the output impedance of the current output pin i out1 varies with dac input code. the i out1 capacitance due to the nmos current steering switches also varies with input code from 70pf to 115pf. an added feature of these devices, especially for waveform genera- tion, is a proprietary deglitcher that reduces glitch energy to below 2nv-s over the dac output voltage range. digital section the ltc1591/ltc1597 are 14-/16-bit wide full parallel data bus inputs. the devices are double-buffered with two 14-/16-bit registers. the double-buffered feature permits the update of several dacs simultaneously. the input register is loaded directly from a 16-bit microprocessor bus when the wr pin is brought to a logic low level. the second register (dac register) is updated with the data from the input register when the ld pin is brought to a logic high level. updating the dac register updates the dac output with the new data. to make both registers transparent for flowthrough mode, tie wr low and ld high. however, this defeats the deglitcher operation and output glitch impulse may increase. the deglitcher is activated on the rising edge of the ld pin. the versatility of the interface also allows the use of the input and dac registers in a master slave or edge-triggered configura- tion. this mode of operation occurs when wr and ld are tied together. the asynchronous clear pin resets the ltc1591/ltc1597 to zero scale and the ltc1591-1/ ltc1597-1 to midscale. clr resets both the input and dac registers. these devices also have a power-on reset. table 1 shows the truth table for the ltc1591/lt1597. unipolar mode (2-quadrant multiplying, v out = 0v to C v ref ) the ltc1591/ltc1597 can be used with a single op amp to provide 2-quadrant multiplying operation as shown in figure 1. with a fixed C 10v reference, the circuits shown give a precision unipolar 0v to 10v output swing. applicatio n s i n for m atio n wu u u figure 1a. unipolar operation (2-quadrant multiplication) v out = 0v to C v ref v cc ltc1591 r fb r fb r ofs r ofs 5v ld ld 3 2 98 28 27 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 33pf v out = 0v to ? ref 1591/97 f01a agnd dgnd wr 10 to 21, 24, 25 wr clr nc clr v ref + lt1001 14-bit dac r1 r2 14 data inputs unipolar binary code table digital input binary number in dac register ? ref (16,383/16,384) ? ref (8,192/16,384) = v ref / 2 ? ref (1/16,384) 0v lsb 1111 1111 11 0000 0000 00 0000 0000 01 0000 0000 00 analog output v out msb 1111 1000 0000 0000 26 nc
14 ltc1591/ltc1597 applicatio n s i n for m atio n wu u u v cc ltc1597 r fb r fb r ofs r ofs 5v ld ld 3 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 33pf v out = 0v to ? ref 1591/97 f01b agnd dgnd wr 10 to 21, 24 to 27 wr clr clr v ref + lt1001 16-bit dac r1 r2 16 data inputs unipolar binary code table digital input binary number in dac register ? ref (65,535/65,536) ? ref (32,768/65,536) = v ref /2 ? ref (1/65,536) 0v lsb 1111 1111 1111 0000 0000 0000 0000 0000 0001 0000 0000 0000 analog output v out msb 1111 1000 0000 0000 figure 1b. unipolar operation (2-quadrant multiplication) v out = 0v to C v ref bipolar mode (4-quadrant multiplying, v out = C v ref to v ref ) the ltc1591/ltc1597 contain on chip all the 4-quadrant resistors necessary for bipolar operation. 4-quadrant multiplying operation can be achieved with a minimum of external components, a capacitor and a dual op amp, as shown in figure 2. with a fixed 10v reference, the circuit shown gives a precision bipolar C 10v to 10v output swing. op amp selection because of the extremely high accuracy of the 14-/16-bit ltc1591/ltc1597, thought should be given to op amp selection in order to achieve the exceptional performance of which the part is capable. fortunately, the sensitivity of inl and dnl to op amp offset has been greatly reduced compared to previous generations of multiplying dacs. op amp offset will contribute mostly to output offset and gain and will have minimal effect on inl and dnl. for the ltc1597, a 500 m v op amp offset will cause about 0.55lsb inl degradation and 0.15lsb dnl degradation with a 10v full-scale range. the main effects of op amp offset will be a degradation of zero-scale error equal to the op amp offset, and a degradation of full-scale error equal to twice the op amp offset. for the ltc1597, the same 500 m v op amp offset (2mv offset for ltc1591) will cause a 3.3lsb zero-scale error and a 6.5lsb full-scale error with a 10v full-scale range. op amp input bias current (i bias ) contributes only a zero- scale error equal to i bias (r fb/ r ofs ) = i bias (6k). for a thorough discussion of 16-bit dac settling time and op amp selection, refer to application note 74, component and measurement advances ensure 16-bit dac settling time . reference input and grounding for optimum performance the reference input of the ltc1597 should be driven by a source impedance of less than 1k w . however, these dacs have been designed to minimize source impedance effects. an 8k w source im- pedance degrades both inl and dnl by 0.2lsb. as with any high resolution converter, clean grounding is important. a low impedance analog ground plane and star grounding should be used. agnd must be tied to the star ground with as low a resistance as possible.
15 ltc1591/ltc1597 applicatio n s i n for m atio n wu u u v cc ltc1591-1 r fb r fb r ofs r ofs 5v ld ld 3 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 33pf v out = ? ref to v ref 1591/97 f02a agnd dgnd + 1/2 lt1112 wr 10 to 21, 24, 25 wr clr clr v ref + 1/2 lt1112 14-bit dac r1 r2 14 data inputs bipolar offset binary code table digital input binary number in dac register v ref (8,191/8,192) v ref (1/8,192) 0v ? ref (1/8,192) ? ref lsb 1111 1111 11 0000 0000 01 0000 0000 00 1111 1111 11 0000 0000 00 analog output v out msb 1111 1000 1000 0111 0000 27 nc 26 nc figure 2a. bipolar operation (4-quadrant multiplication) v out = C v ref to v ref v cc ltc1597-1 r fb r fb r ofs r ofs 5v ld ld 3 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 33pf v out = ? ref to v ref 1591/97 f02b agnd dgnd + 1/2 lt1112 wr 10 to 21, 24 to 27 wr clr clr v ref + 1/2 lt1112 16-bit dac r1 r2 16 data inputs bipolar offset binary code table digital input binary number in dac register v ref (32,767/32,768) v ref (1/32,768) 0v ? ref (1/32,768) ? ref lsb 1111 1111 1111 0000 0000 0001 0000 0000 0000 1111 1111 1111 0000 0000 0000 analog output v out msb 1111 1000 1000 0111 0000 figure 2b. bipolar operation (4-quadrant multiplication) v out = C v ref to v ref
16 ltc1591/ltc1597 typical applicatio n s u v cc ltc1597 r fb r fb r ofs r ofs 5v ld ld 3 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 33pf v out = 0v to v ref 1591/97 f06 agnd dgnd + 1/2 lt1112 wr 10 to 21, 24 to 27 wr clr clr v ref + 1/2 lt1112 16-bit dac r1 r2 16 data inputs noninverting unipolar operation (2-quadrant multiplication) v out = 0v to v ref
17 ltc1591/ltc1597 typical applicatio n s u 16-bit v out dac programmable unipolar/bipolar configuration v cc ltc1597 r fb r fb r ofs r ofs 5v ld ld 3 3 ltc203ac 2 1 6 4 2 unipolar/ bipolar 15v 14 15 16 2 98 28 23 7 22 r1 r com 1 ref 45 0.1 f 6 i out1 15pf v out 1591/97 f04 agnd dgnd + lt1001 + lt1468 wr 10 to 21, 24 to 27 wr clr clr + lt1468 16-bit dac r1 r2 16 data inputs lt1236a-10
18 ltc1591/ltc1597 typical applicatio n s u v cc ltc1597 r fb r fb r ofs r ofs 5v ld 3 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 15pf 1591/97 f05 agnd dgnd + wr 10 to 21, 24 to 27 clr + lt1468 16-bit dac r1 r2 16 data inputs lt1001 6 4 2 15v lt1236a-10 lowpass filter (m)(f c ) 2 n f o = sin rom lookup table parallel delta phase register m phase register phase truncation 16 bits phase accumulator frequency control n = 24 to 32 bits clock n n n n n serial or byte load register s f o digital waveform generator
19 ltc1591/ltc1597 package descriptio n u g package 28-lead plastic ssop (0.209) (ltc dwg # 05-08-1640) dimensions in inches (millimeters) unless otherwise noted. n28 1197 0.255 0.015* (6.477 0.381) 1.370* (34.789) max 34 5 6 7 8 9 10 11 12 21 13 14 15 16 18 17 19 20 22 23 24 25 26 2 27 1 28 0.020 (0.508) min 0.125 (3.175) min 0.130 0.005 (3.302 0.127) 0.065 (1.651) typ 0.045 ?0.065 (1.143 ?1.651) 0.018 0.003 (0.457 0.076) 0.005 (0.127) min 0.100 0.010 (2.540 0.254) 0.009 ?0.015 (0.229 ?0.381) 0.300 ?0.325 (7.620 ?8.255) 0.325 +0.035 0.015 +0.889 0.381 8.255 () *these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 inch (0.254mm) n package 28-lead pdip (narrow 0.300) (ltc dwg # 05-08-1510) g28 ssop 0694 0.005 ?0.009 (0.13 ?0.22) 0 ?8 0.022 ?0.037 (0.55 ?0.95) 0.205 ?0.212** (5.20 ?5.38) 0.301 ?0.311 (7.65 ?7.90) 1234 5 6 7 8 9 10 11 12 14 13 0.397 ?0.407* (10.07 ?10.33) 25 26 22 21 20 19 18 17 16 15 23 24 27 28 0.068 ?0.078 (1.73 ?1.99) 0.002 ?0.008 (0.05 ?0.21) 0.0256 (0.65) bsc 0.010 ?0.015 (0.25 ?0.38) dimensions do not include mold flash. mold flash shall not exceed 0.006" (0.152mm) per side dimensions do not include interlead flash. interlead flash shall not exceed 0.010" (0.254mm) per side * ** 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
20 ltc1591/ltc1597 ? linear technology corporation 1998 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 l fax: (408) 434-0507 l www.linear-tech.com typical applicatio n u 15917f lt/tp 1298 4k ? printed in usa 17-bit sign magnitude dac with bipolar zero error of 140 m v (0.92lsb at 17 bits) at 25 c v cc 15pf ltc1597 r fb r fb r ofs r ofs 5v ld ld 3 3 ltc203ac 2 1 6 4 2 15v 14 15 16 2 98 28 23 7 22 r1 r com 1 ref 4 5 0.1 f 6 i out1 20pf v out 1591/97 f03 agnd dgnd + lt1468 wr 10 to 21, 24 to 27 sign bit wr clr clr + lt1468 16-bit dac r1 r2 16 data inputs lt1236a-10 part number description comments op amps lt1001 precision operational amplifier low offset, low drift lt1112 dual low power, precision picoamp input op amp low offset, low drift lt1468 90mhz, 22v/ m s, 16-bit accurate op amp precise, 1 m s settling to 0.0015% dacs ltc1595/ltc1596 serial 16-bit current output dacs low glitch, 1lsb maximum inl, dnl ltc1650 serial 16-bit voltage output dac low noise and glitch rail-to-rail vout ltc1658 serial 14-bit voltage output dac low power, 8-lead msop rail-to-rail vout adcs ltc1418 14-bit, 200ksps 5v sampling adc 16mw dissipation, serial and parallel outputs ltc1604 16-bit, 333ksps sampling adc 2.5v input, sinad = 90db, thd = 100db ltc1605 single 5v, 16-bit 100ksps adc low power, 10v inputs references lt1236 precision reference ultralow drift, 5ppm/ c, high accuracy 0.05% related parts

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