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unisonic technologies co., ltd LMV393 linear integrated circuit www.unisonic.com.tw 1 of 11 copyright ? 2005 unisonic technologies co., ltd qw-r104-004,a dual general purpose, low volage, comparators ? description the utc LMV393 is a low voltage (2.7-5v) version of the dual comparators. its noise perform ance has been improved by using bipolar differential input and output stages. these comparators also have a unique characteristic in t hat the input common-mode voltage range includes ground even though operated from a single power supply voltage. the utc LMV393 is designed for applications in consumer automotive, mobile communications, notebooks and pda?s, battery powered electronics, general purpose portable device, general purpose low voltage applications. ? features * high precision comparator. * low operating voltage 2.7-5v. * low supply current 100 a/channel (typical). * low input bias current 100na (typical). * low input offset current 2na (typical). * input common mode voltage range includes ground. * low output saturation voltage 0.2v. *pb-free plating product number: LMV393l ? ordering information ordering number normal lead free plating package packing LMV393-d08-t LMV393l-d08-t dip-8 tube LMV393-s08-r LMV393l-s08-r sop-8 tape reel LMV393-s08-t LMV393l-s08-t sop-8 tube LMV393-sm1-r LMV393l-sm1-r msop-8 tape reel LMV393-sm1-t LMV393l-sm1-t msop-8 tube
LMV393 linear integrated circuit unisonic technologies co., ltd 2 of 11 www.unisonic.com.tw qw-r104-004,a ? pin configureation ? block diagram
LMV393 linear integrated circuit unisonic technologies co., ltd 3 of 11 www.unisonic.com.tw qw-r104-004,a ? absolute maximum ratings parameter symbol ratings unit supply voltage v cc 2.7 ~ 5.0 v differential input voltage v in(diff) v cc v voltage on any pin (referred to v- pin) 5.5 v junction temperature t j +150 c operating temperature t opr -40 ~ +85 c storage temperature t stg -65 ~ +150 c note absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only an d functional device operat ion is not implied. ? thermal characteristics parameter symbol ratings unit msop-8 190 dip-8 100 thermal resistance junction to ambient sop-8 ja 150 /w ? dc electrical characteristics (t j =25 , v - =0v, unless otherwise specified.) parameter symbol test conditions min typ max unit input offset voltage v in(off) 1.7 7 mv input offset voltage average drift i i(off) 5 v/ input bias current i i(bias) 100 250 na input offset current i i(off) 2 50 na input voltage range v in -0.1 4.2 v supply current i cc 100 200 a voltage gain g v 20 50 v/mv saturation voltage v sat i sink 4ma 200 400 mv 2.7v 5 40 output sink current 5.0v i sink v out 1.5v 10 50 ma output leakage current i leak 0.003 1 a ? ac electrical characteristics (t j =25 , r l =5.1k ? , v-=0v, unless otherwise specified.) parameter symbol test conditions min typ max unit 2.7v 9 5.0v input overdrive=10mv 8 2.7v 3.8 propagation delay (high to low) 5.0v t phl input overdrive=100mv 3.4 us 2.7v 2 5.0v input overdrive=10mv 3 2.7v 0.7 propagation delay (low to high) 5.0v t plh input overdrive=100mv 0.8 us
LMV393 linear integrated circuit unisonic technologies co., ltd 4 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits basic comparator a basic comparator circuit can convert analog signals to a digital output. the utc LMV393 needs a pull-up resistor connected to the positive supp ly voltage which can make output switch properly. so that when the internal output transistor is off, the output voltage will be pulled up to the extern al positive voltage. the resister should be chosen properly. the higher resister can reduce the power dissipation. the lower resister can improve the capacity of loading output. the range of resister should between 1k to 10k ? . the output voltage of the com parator will be high if the input voltage at the non-inverting pin is greater than the reference voltage at the inverting pi n. on the other hand it will be low. comparator with hysteresis the comparator may oscillate or produce a noisy outpu t if the applied differential input voltage is near the comparator?s offset voltage, especiall y when the input signal is moving slow ly across the comparator?s switching threshold. addition of hysteresis or pos itive feedback can solve this problem. inverting comparator with hysteresis it requires a three resistor network that is referenced to the supply voltage v cc of the comparat or. when the output voltage is high, these resistors can be represented as r1 // r3 in series with r2. the lower set input voltage is defined as:
LMV393 linear integrated circuit unisonic technologies co., ltd 5 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits(cont.) when v in > v a the output voltage is low close to ground. it can be presented as r 2 // r 3 in series with r 1 . the upper trip voltage v a2 is defined as the total hysteresis provided by the network is defined as: to assure that the comparator will always switch corre ctly, the resistors values should be chosen as follow: r pull-up << r load and r 1 > r pull-up . non-inverting comparator with hysteresis it requires a two resistor network to implement a non in verting comparator with hysteresis and with a voltage reference at the inverting input. so when v in is low, the output is also low. if t he output will switch from low to high, v in must rise up to v in1 , and v in1 can be calculated by: when v in is high, the output is also high, in order to make the comparator switch back to low, v in can be calculated by: the hysteresis of this circuit is the difference between v in1 and v in 2 .
LMV393 linear integrated circuit unisonic technologies co., ltd 6 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits(cont.) square wave oscillator comparators are suitable for oscillat or applications. this application us es the minimum number of external components. the output frequency is set by the rc time co nstant which is determined by capacitor c1 and the resistor in the negative feedback r 4 of the comparator. capacitive load at the output would degrade the output slew rate and limit the maximum operating frequency. v + r4 100k 4.3k v + 0 v out r3 100k r2 100k r 1 100k v + c 1 75pf vc va t = 0 va 2 va 1 -vcc vc 1 squarewave oscillator - + t 0 v out at first, assume that the output is high, so the voltage at the inverting input v c is less than the voltage at the non-inverting input va, the capacitor c 1 has to be discharged. when it has charged up to value equal to the positive input voltage v a1 , the comparator output will switch. v a1 will be given by: if: r 1 =r 2 =r 3 then: when the output switches to ground, the value of va is reset by the resistor network: then capacitor c1 discharge through a resistor towards gr ound. the output will return to its high state when the voltage across the capacitor has discharged to a value equal to v a2 .the time to charge the capacitor can be calculated from: where v max =2v cc /3 and v c = v cc /3 one period will be given by: 1/freq = 2t or calc ulating the exponential gi ves: 1/freq = 2(0.694) r 4 c 1 resistors r 3 and r 4 must be at least two times larger than r 5 to insure a reasonable v o . the frequency stability of this circuit should strictly be a function of the external components.
LMV393 linear integrated circuit unisonic technologies co., ltd 7 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits(cont.) free running multivibrator this oscillator circuit can generate a train of stable clock for precise timekeeping applications. we can obtain it by using a resonator as the feedback component. a quartz crys tal in its series-resonant mode can make the circuit oscillating well. for the comparator be switching symmetrically about +v cc /2, the value of r 1 and r 2 must choose equal. the rc time constant of r3 and c 1 is set to be several times greater than the period of the oscillating frequency. when choose crystal, be sure to order seri es resonant with desired temperature coefficient. pulse generator with variable duty cycle: a pulse generator with variable duty cycle can be obtained by creating two separated paths for c 1 charge and discharge into the basic square wave generator. one path, through r 2 and d 2 will charge the capacitor and set the pulse width (t 1 ). the other path, r 1 and d 1 will discharge the capacitor and set the time between pulses (t 2 ). varying resistor r 1 , r 2 can alter the time between pulses and the puls e width. both controls also change the frequency of the generator. the pulse width and time between pulses can be found from: 141 1max (1 ) trc vv e ? =? rise time 251 1max trc vve ? = fall time where max 2 3 cc v v = and max 1 33 cc vv v == then 141 1 2 trc e ? = t 2 is then given by: 251 1 2 trc e ? =
LMV393 linear integrated circuit unisonic technologies co., ltd 8 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits(cont.) - + 15k d1 * r1 1m r2 100k d2 c 1 80pf r 5 1m v+ r 3 1m r 4 1m v out 6 s60 s t o t 1 t 2 -v + v + pulse generator *for large ratios of r1/r2. d1 can be omitted. 0 at last, we get, 141 ln 2 trc = 251 ln 2 trc = these terms have a slight error because v max is not exactly equal to 2/3 v cc but is actually reduced by the diode drop to: max 2 () 3 cc be vvv =? 141 1 2(1 ) trc be e v ? = ? 251 1 2(1 ) trc be e v ? = ? and that?s the exact value we get. 141 ln 2(1 ) be trc v =? 251 ln 2(1 ) be trc v =?
LMV393 linear integrated circuit unisonic technologies co., ltd 9 of 11 www.unisonic.com.tw qw-r104-004,a ? application circuits(cont.) positive peak detector: positive peak detector is basically the comparator operat ed as a unit gain follower with a large holding capacitor from the output to ground. additional transistor is added to the output to provide a low impedance current source. when the output of the comparator goes high, current is passed through the transistor to charge up the capacitor. the only discharge path will be the 1m ohm resistor shunti ng c1 and any load that is connected to the output. the decay time can be altered simply by changing the 1m ? resistor. the output should be used through a high impedance follower to a avoid loading the output of t he peak detector. negative peak detector: for the negative detector, the output transistor of the comparator acts as a low impedance current sink. the only discharge path will be the 1m ? resistor and any load impedance used. decay time is changed by varying the 1m ? resistor.
LMV393 linear integrated circuit unisonic technologies co., ltd 10 of 11 www.unisonic.com.tw qw-r104-004,a ? typical characteristics 1000 0 20 10 400 600 900 30 800 500 300 40 output voltage vs output current at 5v supply output current (ma) output voltage (mv) 50 700 200 +25 100 0 600 0 10 5 200 400 15 500 300 20 output voltage vs output current at 2.7 supply output current (ma) output voltage (mv) +85 +25 100 0 250 2.5 4.5 3.5 50 150 5.5 200 100 input bias current vs supply voltage supply voltage (v) input bias current (na) +85 +25 5 0 v in =0v 5 0 1 0.5 1 3 1.5 4 2 2 response time vs input overdrives negative transition time ( s) output voltage v out (v) 10mv 100 0 overdrive 100mv 20m v 0 input voltage v in (mv) 5 0 6 3 1 3 9 4 2 12 response time for input overdrive positive transition time ( s) output voltage v out (v) 5mv -100 0 overdrive 100mv 20mv 0 input voltage (mv) vcc=5v ta=25 r l =5.1k ? vcc=5v ta=25 r l =5.1k ? 0 1 0.5 1 3 1. 5 2 2 response time vs input overdrives negative transition time ( s) output voltage v out (v) 100 0 overdrive 100m v 20mv 0 input voltage v in (mv) vcc=2.7v ta=25 r l =5.1k ? ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ +85 1100 1200 1300 1400 1500 1600 1700 700 2.5 3 10mv
LMV393 linear integrated circuit unisonic technologies co., ltd 11 of 11 www.unisonic.com.tw qw-r104-004,a ? typical characteristics (cont.) output voltage v out (v) input voltage (mv) utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expe cted to result in personal injury. reproduction in whole or in part is prohibited without the prior writ ten consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.

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