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1 lt 2078/lt 2079 micropower, dual and quad, single supply, precision op amps features n so package with standard pinout n supply current per amplifier: 50 m a max n offset voltage: 70 m v max n offset current: 250pa max n voltage noise: 0.6 m v p-p , 0.1hz to 10hz n current noise: 3pa p-p , 0.1hz to 10hz n offset voltage drift: 0.4 m v/ c n gain bandwidth product: 200khz n slew rate: 0.07v/ m s n single supply operation input voltage range includes ground output swings to ground while sinking current no pull-down resistors needed n output sources and sinks 5ma load current descriptio n u the lt ? 2078 is a micropower dual op amp in 8-pin small outline, standard surface mount package, and lt2079 is a micropower quad op amp offered in the standard 14-pin surface mount package. both devices are optimized for single supply operation at 5v. 15v specifications are also provided. micropower performance of competing devices is achieved at the expense of seriously degrading precision, noise, speed and output drive specifications. the design effort of the lt2078/lt2079 was concentrated on reducing sup- ply current without sacrificing other parameters. the offset voltage achieved is the lowest on any dual or quad nonchopper stabilized op ampCCmicropower or other- wise. offset current, voltage and current noise, slew rate and gain bandwidth product are all two to ten times better than on previous micropower op amps. both the lt2078/lt2079 can be operated from a single supply (as low as one lithium cell or two nicd batteries). the input range goes below ground. the all npn output stage swings to within a few millivolts of ground while sinking currentCCno power consuming pull-down resis- tors are needed. for applications requiring dip packages refer to the lt1078/lt1079. , ltc and lt are registered trademarks of linear technology corporation. n battery or solar-powered systems portable instrumentation remote sensor amplifier satellite circuitry n micropower sample-and-hold n thermocouple amplifier n micropower filters typical applicatio n u single battery, micropower, gain = 100, instrumentation amplifier distribution of input offset voltage input offset voltage ( v) 120 number of op amps 0 80 2078/79 ?ta02 80 40 40 800 700 600 500 400 300 200 100 0 120 v s = 5v, 0v 5000 op amps + + inverting ?nput 1m 2 3 1 6 5 7 a 1/2 lt2078 10.1k 1m 10.1k noninverting +input b 1/2 lt2078 4 8 3v (li-ion) out typical performance input offset voltage = 40 v input offset current = 0.2na total power dissipation = 240 w common mode rejection = 110db (amplifier limited) gain bandwidth product = 200khz output noise = 85 v p-p 0.1hz to 10hz = 300 v rms over full bandwidth input range = 0.03v to 1.8v output range = 0.03v to 2.3v (0.3mv v in + ?v in 23mv) outputs sink current?o pull-down resistors lt2078/79 ?ta01 applicatio n s u
2 lt2078/lt 2079 absolute m axi m u m ratings w ww u supply voltage ...................................................... 22v differential input voltage ....................................... 30v input voltage ............... equal to positive supply voltage ............5v below negative supply voltage output short-circuit duration .......................... indefinite specified temperature range commercial ............................................. 0 c to 70 c industrial ............................................ C 40 c to 85 c storage temperature range ................. C 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c t jmax = 150 c, q ja = 150 c/ w t jmax = 150 c, q ja = 190 c/ w consult factory for military grade parts. v s = 5v, 0v, v cm = 0.1v, v o = 1.4v, t a = 25 c, unless otherwise noted. lt2078ac/lt2078ai lt2078c/lt2078i lt2079ac/lt2079ai lt2079c/lt2079i symbol parameter conditions (note 1) min typ max min typ max units v os input offset voltage lt2078 30 70 40 120 m v lt2079 35 110 40 150 m v d v os long term input offset 0.4 0.5 m v/mo d time voltage stability i os input offset current 0.05 0.25 0.05 0.35 na i b input bias current 6 8 6 10 na e n input noise voltage 0.1hz to 10hz (note 2) 0.6 1.2 0.6 m v p-p input noise voltage density f o = 10hz (note 2) 29 45 29 nv ? hz f o = 1000hz (note 2) 28 37 28 nv ? hz i n input noise current 0.1hz to 10hz (note 2) 2.3 4.0 2.3 pa p-p input noise current density f o = 10hz (note 2) 0.06 0.10 0.06 pa ? hz f o = 1000hz 0.02 0.02 pa ? hz input resistance (note 3) differential mode 400 800 300 800 m w common mode 6 6 g w input voltage range 3.5 3.8 3.5 3.8 v 0 C 0.3 0 C 0.3 v cmrr common mode rejection ratio v cm = 0v to 3.5v 95 110 92 108 db psrr power supply rejection ratio v s = 2.3v to 12v 100 114 98 114 db electrical characteristics order part number lt2078acs8 LT2078AIS8 lt2078cs8 lt2078is8 2078a 2078ai 2078 2078i part marking package/order i n for m atio n w u u order part number lt2079ac lt2079ai lt2079c lt2079i 1 2 3 4 8 7 6 5 top view v + out b in b +in b out a in a +in a v s8 package 8-lead plastic so a b top view s package 14-lead plastic so 1 2 3 4 5 6 7 14 13 12 11 10 9 8 out a in a +in a v + +in b in b out b out d in d +in d v +in c in c out c a d b c
3 lt 2078/lt 2079 electrical characteristics v s = 5v, 0v, v cm = 0.1v, v o = 1.4v, t a = 25 c, unless otherwise noted. lt2078ac/lt2078ai lt2078c/lt2078i lt2079ac/lt2079ai lt2079c/lt2079i symbol parameter conditions (note 1) min typ max min typ max units a vol large-signal voltage gain v o = 0.03v to 4v, no load 200 1000 150 1000 v/mv v o = 0.03v to 3.5v, r l = 50k 150 600 120 600 v/mv maximum output voltage output low, no load 3.5 6 3.5 6 mv swing output low, 2k to gnd 0.55 1.0 0.55 1.0 mv output low, i sink = 100 m a 95 130 95 130 mv output high, no load 4.2 4.4 4.2 4.4 v output high, 2k to gnd 3.5 3.9 3.5 3.9 v sr slew rate a v = 1, v s = 2.5v 0.04 0.07 0.04 0.07 v/ m s gbw gain bandwidth product f o 20khz 200 200 khz i s supply current per amplifier 38 50 39 55 m a channel separation d v in = 3v, r l = 10k, f 10hz 110 110 db minimum supply voltage (note 4) 2.2 2.3 2.2 2.3 v v s = 5v, 0v, v cm = 0.1v, v o = 1.4v, C 40 c t a 85 c for i grades, unless otherwise noted. lt2078ai/lt2079ai lt2078i/lt2079i symbol parameter conditions min typ max min typ max units v os input offset voltage lt2078 l 70 250 95 370 m v lt2079 l 80 280 100 400 m v d v os input offset voltage drift lt2078 l 0.4 1.8 0.5 2.5 m v/ c d t (note 5) lt2079 l 0.6 3.0 0.6 3.5 m v/ c i os input offset current l 0.07 0.70 0.1 1.0 na i b input bias current l 710 712 na cmrr common mode rejection ratio v cm = 0.05v to 3.2v l 90 106 86 104 db psrr power supply rejection ratio v s = 3.1v to 12v l 96 110 92 110 db a vol large-signal voltage gain v o = 0.05v to 4v, no load l 110 600 80 600 v/mv v o = 0.05v to 3.5v, r l = 50k l 80 400 60 400 v/mv maximum output voltage output low, no load l 4.5 8 4.5 8 mv swing output low, i sink = 100 m a l 125 170 125 170 mv output high, no load l 3.9 4.2 3.9 4.2 v output high, 2k to gnd l 3.0 3.7 3.0 3.7 v i s supply current per amplifier l 43 60 45 70 m a lt2078ac/lt2079ac lt2078c/lt2079c symbol parameter conditions min typ max min typ max units v os input offset voltage lt2078 l 50 150 60 240 m v lt2079 l 60 180 70 270 m v d v os input offset voltage drift lt2078 l 0.4 1.8 0.5 2.5 m v/ c d t (note 5) lt2079 l 0.5 3.0 0.6 3.5 m v/ c i os input offset current l 0.06 0.35 0.06 0.50 na i b input bias current l 69 611 na cmrr common mode rejection ratio v cm = 0v to 3.4v l 92 108 88 106 db psrr power supply rejection ratio v s = 2.6v to 12v l 98 112 95 112 db v s = 5v, 0v, v cm = 0.1v, v o = 1.4v, 0 c t a 70 c, unless otherwise noted (note 6).
4 lt2078/lt 2079 electrical characteristics lt2078ac/lt2079ac lt2078c/lt2079c symbol parameter conditions min typ max min typ max units a vol large-signal voltage gain v o = 0.05v to 4v, no load l 150 750 110 750 v/mv v o = 0.05v to 3.5v, r l = 50k l 110 500 80 500 v/mv maximum output voltage output low, no load l 4.0 7 4.0 7 mv swing output low, i sink = 100 m a l 105 150 105 150 mv output high, no load l 4.1 4.3 4.1 4.3 v output high, 2k to gnd l 3.3 3.8 3.3 3.8 v i s supply current per amplifier l 40 55 42 63 m a v s = 5v, 0v, v cm = 0.1v, v o = 1.4v, 0 c t a 70 c, unless otherwise noted. v s = 15v, t a = 25 c, unless otherwise noted. lt2078ac/lt2078ai lt2078c/lt2078i lt2079ac/lt2079ai lt2079c/lt2079i symbol parameter conditions min typ max min typ max units v os input offset voltage lt2078 50 250 70 350 m v lt2079 60 350 80 450 m v i os input offset current 0.05 0.25 0.05 0.35 na i b input bias current 6 8 6 10 na input voltage range 13.5 13.8 13.5 13.8 v C15.0 C15.3 C15.0 C15.3 v cmrr common mode rejection ratio v cm = 13.5v, C15v 98 114 95 114 db psrr power supply rejection ratio v s = 5v, 0v to 18v 100 114 98 114 db a vol large-signal voltage gain v o = 10v, r l = 50k 1000 5000 1000 5000 v/mv v o = 10v, r l = 2k 400 1100 300 1100 v/mv v out maximum output voltage r l = 50k 13.0 14.0 13.0 14.0 v swing r l = 2k 11.0 13.2 11.0 13.2 v sr slew rate 0.06 0.10 0.06 0.10 v/ m s i s supply current per amplifier 46 65 47 75 m a v s = 15v, C 40 c t a 85 c for i grades, unless otherwise noted. lt2078ai/lt2079ai lt2078i/lt2079i symbol parameter conditions min typ max min typ max units v os input offset voltage lt2078 l 90 430 120 600 m v lt2079 l 100 500 130 700 m v d v os input offset voltage drift lt2078 l 0.5 1.8 0.6 2.5 m v/ c d t (note 5) lt2079 l 0.6 3.0 0.7 3.8 m v/ c i os input offset current l 0.07 0.70 0.1 1.0 na i b input bias current l 710 712 na a vol large-signal voltage gain v o = 10v, r l = 5k l 200 700 150 700 v/mv cmrr common mode rejection ratio v cm = 13v, C14.9v l 92 110 88 110 db psrr power supply rejection ratio v s = 5v, 0v to 18v l 96 110 92 110 db maximum output voltage swing r l = 5k l 11.0 13.5 11.0 13.5 v i s supply current per amplifier l 52 80 54 95 m a
5 lt 2078/lt 2079 electrical characteristics v s = 15v, 0 c t a 70 c, unless otherwise noted (note 6). lt2078ac/lt2079ac lt2078c/lt2079c symbol parameter conditions min typ max min typ max units v os input offset voltage lt2078 l 70 330 90 460 m v lt2079 l 80 410 100 540 m v d v os input offset voltage drift lt2078 l 0.5 1.8 0.6 2.5 m v/ c d t (note 5) lt2079 l 0.6 3.0 0.7 3.8 m v/ c i os input offset current l 0.06 0.35 0.06 0.50 na i b input bias current l 69 611 na a vol large-signal voltage gain v o = 10v, r l = 5k l 300 1200 250 1200 v/mv cmrr common mode rejection ratio v cm = 13v, C15v l 95 112 92 112 db psrr power supply rejection ratio v s = 5v, 0v to 18v l 98 112 95 112 db maximum output voltage swing r l = 5k l 11.0 13.6 11.0 13.6 v i s supply current per amplifier l 49 73 50 85 m a the l denotes specifications which apply over the full operating temperature range. note 1: typical parameters are defined as the 60% yield of parameter distributions of individual amplifiers, i.e., out of 100 lt2079s (or 100 lt2078s) typically 240 op amps (or 120) will be better than the indicated specification. note 2: this parameter is tested on a sample basis only. all noise parameters are tested with v s = 2.5v, v o = 0v. note 3: this parameter is guaranteed by design and is not tested. note 4: power supply rejection ratio is measured at the minimum supply voltage. the op amps actually work at 1.8v supply but with a typical offset skew of C 300 m v. note 5: this parameter is not 100% tested. note 6: the lt2078c/lt2079c are designed, characterized and expected to meet the industrial temperature limits, but are not tested at C 40 c and 85 c. i-grade parts are guaranteed. typical perfor m a n ce characteristics u w input bias current vs common mode voltage common mode voltage (v) ? input bias current (na) 0 ? ? ? ? ?0 ?2 0123 lt2078/79 ?tpc03 4 t a = 125 c t a = 55 c v s = 5v, 0v t a = 25 c input bias and offset currents vs temperature temperature ( c) ?0 bias current (na) offset current (pa) 100 50 0 ? ? ? 0 50 75 lt2078/79 ?tpc02 ?5 25 100 125 i os i b v s = 5v, 0v to 15v distribution of offset voltage drift with temperature offset voltage drift with temperature ( v/ c) percent of units (%) 25 20 15 10 5 0 lt2078/79 ?tpc01 ? ? 0 1 2 v s = 5v, 0v v cm = 0.1v 80 lt2078's 25 lt2079's = 260 op amps
6 lt2078/lt 2079 time (sec) 0 noise voltage (0.4 v/div) 8 lt2078/79 ?tpc04 2 4 6 10 channel a channel b t a = 25 c v s = 2.5v typical perfor m a n ce characteristics u w noise spectrum 0.01hz to 10hz noise time (sec) 0 noise voltage (0.4 v/div) 80 lt2078/79 ?tpc05 20 40 60 100 channel b t a = 25 c v s = 2.5v channel a 0.4 v frequency (hz) 0.1 1 100 10 voltage noise density (nv/ ? hz) current noise density (fa/ ? hz) 100 30 1000 300 10 1000 lt2078/79 ?tpc06 current noise voltage noise 1/f corner 0.7hz t a = 25 c v s = 2.5v (at v s = 15v voltage noise is 4% less current noise is unchanged) warm-up drift long term stability of two representative units (lt2078) 10hz voltage noise distribution voltage noise density (nv/ ? hz) 25 lt2078/79 ?tpc07 30 35 40 percent of units 35 30 25 20 15 10 5 0 t a = 25 c v s = 2.5v time after power-on (minutes) 0 change in offset voltage ( v) lt2078/79 ?tpc09 1 2 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 3 t a = 25 c v s = 15v warm up drift at v s = 5v, 0v is immeasurably low lt2079 lt2078 time (months) 0 offset voltage change ( v) 1234 lt2078/79 ?tpc08 5 15 10 5 0 ? 10 ?5 t a = 25 c, v s = 5v, 0v v cm = 0.1v 1a 2b 1b 2a output voltage swing vs load current output saturation vs temperature vs sink current minimum supply voltage positive supply voltage (v) 0 input offset voltage ( v) 100 0 100 200 300 400 500 lt2078/79 ?tpc10 1 23 v = 0v 0.1v v cm 0.4v 125 c ?5 c 0 c 25 c 70 c nonfunctional temperature ( c) ?0 saturation voltage (mv) 1000 100 10 1 25 125 lt2078/79 ?tpc11 0 25 50 100 75 i sink = 2ma i sink = 1ma i sink = 100 a i sink = 1 a no load r l = 5k to gnd i sink = 10 a v s = 5v, 0v sourcing or sinking load current (ma) 0.01 output voltage swing (v) v + v + ?1 v + ?2 v + 2 v + 1 v 10 lt2078/79 ?tpc11.5 0.1 1 125 c 25 c ?5 c 125 c ?5 c 25 c 0.1hz to 10hz noise
7 lt 2078/lt 2079 typical perfor m a n ce characteristics u w voltage gain vs load resistance load resistance to ground ( ) 100 100k voltage gain (v/v) 1m 10m 10k 100k 1k 1m lt2078/79 ?tpc14 25 c ?5 c 125 c 25 c ?5 c 125 c v s = 15v v s = 5v, 0v capacitive load handling gain, phase vs frequency frequency (khz) 30 30 20 10 0 ?0 100 300 ltc2078/79 tpc12 voltage gain (db) 100 120 140 160 180 200 phase shift (deg) 10 1000 phase margin 58 phase margin 46 5v, 0v 15v 15v 5v, 0v voltage gain vs frequency frequency (hz) 0.01 voltage gain (db) 1m lt2078/79 ?tpc13 1 100 10k 140 120 100 80 60 40 20 0 ?0 0.1 10 1k 100k v s = 15v v s = 5v, 0v t a = 25 c slew rate, gain bandwidth product and phase margin vs temperature temperature ( c) ?0 gain bandwidth product (khz) slew rate (v/ s) phase margin (deg) 0.12 0.10 0.08 0.06 0.04 240 220 200 180 160 75 65 55 45 0 50 75 lt2078/79 ?tpc15 ?5 25 100 125 slew = 15v gbw = 15v gbw = 5v, 0v slew = 5v, 0v f m = 15v f m = 5v, 0v f o = 20khz channel separation vs frequency frequency (hz) 1 channel separation (db) 120 100 80 60 40 20 0 10 100 1k 10k lt2078/79 ?tpc16 100k 1m t a = 25 c v s = 2.5v v in = 3v p-p r l = 10k capacitive load (pf) 10 overshoot (%) 120 100 80 60 40 20 0 10000 lt2078/79 ?tpc17 1000 100 t a = 25 c v s = 5v, 0v a v = 1 a v = 10 a v = 5 power supply rejection ratio vs frequency undistorted output swing vs frequency common mode rejection ratio vs frequency frequency (hz) 10 common mode rejection ratio (db) 100 1k 10k 100k lt2078/79 ?tpc19 1m t a = 25 c 120 100 80 60 40 20 0 v s = 15v v s = 5v, 0v frequency (khz) 0.01 peak-to-peak output swing, v s = 15v (v) peak-to-peak output swing, v s = 5v, 0v (v) 30 20 10 0 5 4 3 2 1 0 100 lt2078/79 ?tpc18 110 v s = 5v, 0v r l 3 100k v s = 15v r l 3 100k v s = 15v r l = 30k v s = 5v, 0v r l 3 1k t a = 25 c load r l , to gnd frequency (hz) 0.1 power supply rejection ratio (db) 120 100 80 60 40 20 0 100 10k lt2078/79 ?tpc20 110 1k 100k 1m t a = 25 c v s = 2.5v + 1v p-p sine wave positive supply negative supply
8 lt2078/lt 2079 typical perfor m a n ce characteristics u w supply current vs temperature temperature ( c) ?0 supply current per amplifier ( a) 55 50 45 40 35 30 25 25 75 lt2078/79 ?tpc21 ?5 0 50 100 125 v s = 15v v s = 5v, 0v small-signal transient response v s = 5v, 0v 20mv/div a v = 1 10 m s/div c l = 15pf input 50mv to 150mv lt2078/79 ? tpc24 0v closed-loop output impedance frequency (hz) output impedance ( ) 1k 100 10 1 0.1 lt2078/79 ?tpc23 10 100 1k 10k 100k a v = 100 a v = 10 a v = 1 small-signal transient response v s = 15v 20mv/div a v = 1 10 m s/div c l = 15pf lt2078/79 ? tpc26 0v common mode range vs temperature temperature ( c) ?0 common mode range (v) 25 0 25 50 75 lt2078/79 ?tpc22 125 v + v + ?1 v + ?2 v + 1 v v ?1 100 v + = 2.5v to 18v v = 0v to 18v small-signal transient response v s = 2.5v 20mv/div a v = 1 10 m s/div c l = 15pf lt2078/79 ? tpc25 0v large-signal transient response v s = 5v, 0v 1v/div a v = 1, no load 50 m s/div input pulse 0v to 3.8v lt2078/79 ? tpc27 large-signal transient response v s = 15v 5v/div a v = 1 100 m s/div no load lt2078/79 ? tpc28 0v 0v
9 lt 2078/lt 2079 sche m atic w w si plified 1/2 lt2078, 1/4 lt2079 10k 10k 2.2k 5.6k q5 q6 q11 600 600 q1 q21 q2 q22 q9 c2 175pf 6.2k q7 q28 4 1 q12 q3 q16 q14 q29 q4 q24 8.6k c1 50pf c5 2.5pf q27 v + q10 q17 q8 6.2k q19 q18 q15 q32 1.3k 3.6k q37 q30 1 3 q25 c4 4pf 2.9k 3k q31 c3 40pf q23 q20 1.35k 30 q34 q36 out q26 30 q35 5k q54 1 1 2 150k q33 10k v + q38 5.35k q45 q55 q51 q42 q44 v + v q46 q47 11.5k v + 12.5k q40 q41 q48 9.1k q43 v 700k 700k lt2078/79 ?simplified schem in ? in + q50 q49 j1 q39 q53 q52 4a
10 lt2078/lt 2079 applicatio n s i n for m atio n wu u u the lt2078/lt2079 devices are fully specified with v + = 5v, v C = 0v, v cm = 0.1v. this set of operating conditions appears to be the most representative for battery powered micropower circuits. offset voltage is internally trimmed to a minimum value at these supply voltages. when 9v or 3v batteries or 2.5v dual supplies are used, bias and offset current changes will be minimal. offset voltage changes will be just a few microvolts as given by the psrr and cmrr specifications. for example, if psrr = 114db (=2 m v/v), at 9v the offset voltage change will be 8 m v. similarly, v s = 2.5v, v cm = 0v is equivalent to a common mode voltage change of 2.4v or a v os change of 7 m v if cmrr = 110db (3 m v/v). a full set of specifications is also provided at 15v supply voltages for comparison with other devices and for com- pleteness. single supply operation the lt2078/lt2079 is quite tolerant of power supply bypassing. in some applications requiring faster settling time the positive supply pin of the lt2078/lt2079 should be bypassed with a small capacitor (about 0.1 m f). the same is true for the negative supply pin when using split supplies. the lt2078/lt2079 are fully specified for single supply operation, i.e., when the negative supply is 0v. input common mode range goes below ground and the output swings within a few millivolts of ground while sinking current. all competing micropower op amps either cannot swing to within 600mv of ground (op-20, op-220, op- 420) or need a pull-down resistor connected to the output to swing to ground (op-90, op-290, op-490, ha5141/42/ 44). this difference is critical because in many applica- tions these competing devices cannot be operated as micropower op amps and swing to ground simultaneously. as an example, consider the instrumentation amplifier shown on the front page. when the common mode signal is low and the output is high, amplifier a has to sink current. when the common mode signal is high and the output low, amplifier b has to sink current. the competing devices require a 12k pull-down resistor at the output of amplifier a and a 15k at the output of b to handle the specified signals. (the lt2078 does not need pull-down resistors.) when the common mode input is high and the output is high these pull-down resistors draw 300 m a (150 m a each), which is excessive for micropower applications. the instrumentation amplifier is by no means the only application requiring current sinking capability. in seven of the nine single supply applications shown in this data sheet the op amps have to be able to sink current. in two of the applications the first amplifier has to sink only the 6na input bias current of the second op amp. the compet- ing devices, however, cannot even sink 6na without a pull-down resistor since the output of the lt2078/lt2079 cannot go exactly to ground, but can only approach ground to within a few millivolts, care should be exercised to ensure that the output is not saturated. for example, a 1mv input signal will cause the amplifier to set up in its linear region in the gain 100 configuration shown in figure 1, but is not enough to make the amplifier function properly in the voltage follower mode. single supply operation can also create difficulties at the input. the driving signal can fall below 0v inadvertently or on a transient basis. if the input is more than a few hundred millivolts below ground, two distinct problems can occur on previous single supply designs, such as the lm124, lm158, op-20, op-21, op-220, op-221, op-420 (1 and 2), op-90/290/490 (2 only): figure 1a. gain 100 amplifier figure 1b. voltage follower + 5v 1mv r 99r 100mv lt2078/79 ?f02a + 5v 1mv output saturation ? 3.5mv lt2078/79 ?f02b
11 lt 2078/lt 2079 applicatio n s i n for m atio n wu u u 1. when the input is more than a diode drop below ground, unlimited current will flow from the substrate (v C terminal) to the input. this can destroy the unit. on the lt2078/lt2079, resistors in series with the input protect the devices even when the input is 5v below ground. 2. when the input is more than 400mv below ground (at 25 c), the input stage saturates and phase reversal occurs at the output. this can cause lockup in servo systems. due to a unique phase reversal protection cir- cuitry, the lt2078/lt2079 output does not reverse, as illustrated in figure 2, even when the inputs are at C 1v. distortion there are two main contributors of distortion in op amps: distortion caused by nonlinear common mode rejection and output crossover distortion as the output transitions from sourcing to sinking current. the common mode rejection of the lt2078/lt2079 is very good, typically 108db. therefore, as long as the input operates in the normal common mode range, there will be very little common mode induced distortion. if the op amp is oper- ating inverting there is no common mode induced distor- tion. crossover distortion will increase as the output load resistance decreases. for the lowest distortion the lt2078/ lt2079 should be operated with the output always sourc- ing current, this is usually accomplished by putting a resistor from the output to v C . in an inverting configura- tion with no load, the output will source and sink current through the feedback resistor. high value feedback resis- tors will reduce crossover distortion and maintain micropower operation. matching specifications in many applications the performance of a system de- pends on the matching between two op amps, rather than figure 2. voltage follower with input exceeding the negative common mode range (v s = 5v, 0v) 2v 0v 6v p-p input 1ms/div C1v to 5v lt2078/79 ? f01a 1ms/div lt2078/lt2079 no phase reversal lt2078/79 ? f01c 2v 0v 4v 1ms/div op-90 exhibits output phase reversal lt2078/79 ? f01b 2v 0v 4v 4v table 1 lt2078ac/lt2079ac/lt2078ai/lt2079ai lt2078c/lt2079c/lt2078i/lt2079i parameter 50% yield 98% yield 50% yield 98% yield units v os match, d v os lt2078 30 110 50 190 m v lt2079 40 150 50 250 m v temperature coefficient d v os 0.5 1.2 0.6 1.8 m v/ c average noninverting i b 6 8610 na match of noninverting i b 0.12 0.4 0.15 0.5 na cmrr match 120 100 117 97 db psrr match 117 105 117 102 db
12 lt2078/lt 2079 applicatio n s i n for m atio n wu u u 4 v s = 5v, 0v 200 m s/div lt2078/79 ? f03 2 0 0 C100 input (mv) output (v) figure 3. comparator rise response time to 10mv, 5mv, 2mv overdrives v s = 5v, 0v 200 m s/div lt2078/79 ? f04 0 100 0 input (mv) output (v) 4 2 figure 4. comparator fall response time to 10mv, 5mv, 2mv overdrives the individual characteristics of the two devices, the two and three op amp instrumentation amplifier configura- tions shown in this data sheet are examples. matching characteristics are not 100% tested on the lt2078/lt2079. some specifications are guaranteed by definition. for example, 70 m v maximum offset voltage implies that mis- match cannot be more than 140 m v. 95db (= 17.5 m v/v) cmrr means that worst-case cmrr match is 89db (= 35 m v/v). however, table 1 can be used to estimate the expected matching performance at v s = 5v, 0v between the two sides of the lt2078, and between amplifiers a and d, and between amplifiers b and c of the lt2079. comparator applications the single supply operation of the lt2078/lt2079 and its ability to swing close to ground while sinking current lends itself to use as a precision comparator with ttl compatible output. typical applicatio n s u micropower, 10ppm/ c, 5v reference gain of 10 difference amplifier + 1m 1m 10m output 0.0035v to 2.4v 1/2 lt2078 bandwidth = 20khz output offset = 0.7mv output noise = 80 v p-p (0.1hz to 10hz) 260 v rms over full bandwidth the usefulness of difference amplifiers is limited by the fact that the input resistance is equal to the source resistance. the picoampere offset current and low current noise of the lt2078 allows the use of 1m source resistors without degradation in performance. in addition, with megohm resistors micropower operation can be maintained lt2078/79 ?ta04 ?n +in 10m 3v + + 2m 220k 120k 3 2 1 8 4 1/2 lt2078 9v 5v out 1m 6 5 7 lt1034bc-1.2 510k 1m 5.000v out ?v 510k 1% 20k 160k 1% 1/2 lt2078 supply current = 9v battery = 115 a 9v battery = 85 a output noise = 36 v p-p , 0.1hz to 10hz the lt2078 contributes less than 3% of the total output noise and drift with time and temperature. the accuracy of the 5v output depends on the matching of the two 1m resistors lt2078/79 ?ta03
13 lt 2078/lt 2079 typical applicatio n s u + 9 10 8 1/4 lt2079 + + + r2 1m r2 1m 1/4 lt2079 1/4 lt2079 1/4 lt2079 3 2 1 r1 1m r1 1m r g 200k 6 5 7 12 13 14 r3 9.1m r3 9.1m 9v 4 11 2r 20m output 4mv to 8.2v r 10m 2r 20m ?n +in gain = 1 + () 2r1 r g r3 r2 = 100 for values shown lt2078/79 ?ta05 input bias current typically < 150pa input resistance = 3r = 30m for values shown negative common mode limit = (i b )(2r) + 20mv ? 140mv gain bandwidth product = 1.8mhz picoampere input current, triple op amp instrumentation amplifier with bias current cancellation 85v, C100v common mode range instrumentation amplifier (a v = 10) + + 6 5 7 1/2 lt2078 100k 100k 1/2 lt2078 2 3 1 output 8v to 9v lt2078/79 ?ta06 bandwidth = 2khz output offset = 8mv output noise = 0.8mv p-p (0.1hz to 10hz) = 1.4mv rms over full bandwidth (dominated by resistor noise) 9v ?v 8 4 1m 10m 1m 10m 10m +in ?n input resistance = 10m absolute value circuit (full-wave rectifier) + + 5 6 7 1/2 lt2078 1/2 lt2078 2 3 1 output lt2078/79 ?ta08 v omin = 4mv no distortion to 100hz 5v 8 4 200k 200k input 1n4148 3.5v 3.5v 0v 3.5v half-wave rectifier + 1/2 lt2078 output lt2078/79 ?ta07 v omin = 6mv no distortion to 100hz 3v 2m 2m 1m input 1.8v ?.8v 1.8v 0v programmable gain amplifier (single supply) 13 12 14 out + 1/4 lt2079 9 10 + 1/4 lt2079 6 5 + 1/4 lt2079 2 3 88 3 1 2 7 4 9 a c b + 1/4 lt2079 7 cd4016b 13 5 6 11 4 11 1 3v to 18v 3v to 18v 1m 100k 10k 1.11k in lt2078/79 ?ta09 error due to switch on resistance, leakage current, noise and transients are eliminated cd4016b gain pin 13 pin 5 pin 6 1000 high low low 100 low high low 10 low low high
14 lt2078/lt 2079 typical applicatio n s u single supply, micropower, second order lowpass filter with 60hz notch + + 6 5 7 1/2 lt2078 2.64m 0.1% 2.64m 0.1% 1/2 lt2078 3 2 1 output typical offset ? 600 v lt2078/79 ?ta10 5v 8 4 1.35m 0.1% in 2000pf 0.5% 1000pf 0.5% 1000pf 0.5% 0.02 f 5.1m 1% 120k 5% 100pf 0.01 f 27.6k 0.1% 27.6k 0.1% f c = 40hz q = 30 micropower multiplier/divider + 6 5 13 12 1/4 lt2079 4 11 714 + 2 3 1/4 lt2079 1 + 9 10 1/4 lt2079 8 1.5v to 9v 9v 505k 0.1% 505k 0.1% 505k 0.1% 220pf 220pf 30k 5% 30k 5% q1 + 220pf 30k 5% y input (5mv to 50v) x input (5mv to 50v) q2 q4 499k 0.5% 10k gain z input (5mv to 50v) output (5mv to 8v) 1/4 lt2079 q1,q2, q3, q4 = mat-04 typical linearity = 0.01% of full-scale output q3 output = , positive inputs only (x)(y) (z) negative supply current = 165 a + x + y+ z + out 500k positive supply current = 165 a + bandwidth (< 3v p-p signal): x and y inputs = 10khz z input = 4khz out 500k lt2078/79 ?ta11 micropower dead zone generator + 2 3 1 1/4 lt2079 510k 1m** 1m** 1m* q1 2n4393 + 6 5 7 1/4 lt2079 + 9 10 8 1/4 lt2079 + 13 12 14 1/4 lt2079 1m** q4 q2 q3 470k 1m* gain 200k 510k 1m** 510k 4 11 9v 1m 1m 680k 1m 1n914 1n914 q5 ?v q6 2n4393 1000pf v set dead zone control input 0.4v to 5v v out lt2078/79 ?ta12 bipolar symmetry is excellent because one device, q2, sets both limits supply current ? 240 a bandwidth = 150khz input * ** 1% film ratio match 0.05% q2, q3, q4, q5 ca3096 transistor array v set v set v out v in
15 lt 2078/lt 2079 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. typical applicatio n s u lead-acid low-battery detector with system shutdown + + 2 3 1 6 5 7 8 4 1/2 lt2078 1/2 lt2078 2m 1% 2m 1% 255k 1% 280k 1% 910k 5% lt1004-1.2 lo = battery low (if v s < 10.90v) lo = system shutdown (if v s < 10.05v) battery output lt2078/79 ?ta13 total supply current = 105 a 12v dimensions in inches (millimeters) unless otherwise noted. package descriptio n u 1 2 3 4 0.150 ?0.157** (3.810 ?3.988) 14 13 0.337 ?0.344* (8.560 ?8.738) 0.228 ?0.244 (5.791 ?6.197) 12 11 10 9 5 6 7 8 0.016 ?0.050 0.406 ?1.270 0.010 ?0.020 (0.254 ?0.508) 45 0 ?8 typ 0.008 ?0.010 (0.203 ?0.254) s14 0695 0.053 ?0.069 (1.346 ?1.752) 0.014 ?0.019 (0.355 ?0.483) 0.004 ?0.010 (0.101 ?0.254) 0.050 (1.270) typ dimension does not include mold flash. mold flash shall not exceed 0.006" (0.152mm) per side dimension does not include interlead flash. interlead flash shall not exceed 0.010" (0.254mm) per side * ** s package 14-lead plastic small outline (narrow 0.150) (ltc dwg # 05-08-1610) s8 package 8-lead plastic small outline (narrow 0.150) (ltc dwg # 05-08-1610) 1 2 3 4 0.150 ?0.157** (3.810 ?3.988) 8 7 6 5 0.189 ?0.197* (4.801 ?5.004) 0.228 ?0.244 (5.791 ?6.197) 0.016 ?0.050 0.406 ?1.270 0.010 ?0.020 (0.254 ?0.508) 45 0 ?8 typ 0.008 ?0.010 (0.203 ?0.254) so8 0695 0.053 ?0.069 (1.346 ?1.752) 0.014 ?0.019 (0.355 ?0.483) 0.004 ?0.010 (0.101 ?0.254) 0.050 (1.270) bsc dimension does not include mold flash. mold flash shall not exceed 0.006" (0.152mm) per side dimension does not include interlead flash. interlead flash shall not exceed 0.010" (0.254mm) per side * **
16 lt2078/lt 2079 linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 l fax : (408) 434-0507 l telex : 499-3977 lt/gp 1096 7k ? printed in usa ? linear technology corporation 1996 platinum rtd signal conditioner with curvature correction + 3 2 1 8 4 1/2 lt2078 lt1004-1.2 + 6 5 7 1/2 lt2078 13k* 12.3k* 1k** 1k** 1k** r p 1k at 0 c 43.2k** 1.21m* (select at 110 c) 5k 220 c trim 1 f 10k* 50k 5 c trim 1 f 0.02v to 2.2v out = 2 c to 220 c 0.1 c 3v (lithium) r p ** * = rosemount 118mf = trw mar-6 0.1% = 1% metal film lt2078/79 ?ta14 related parts part number description comments lt1178/lt1179 dual/quad 17 m a max, single supply precision op amps 70 m v v os max and 2.5 m v/ c drift max, 85khz gbw, 0.04v/ m s slew rate, input/output common mode includes ground lt1211/lt1212 14mhz, 7v/ m s single supply dual and quad precision op amps 275 m v v os max, 6 m v/ c drift max input voltage range includes ground lt1490/lt1491 dual/ quad micropower rail-to-rail input and output op amps single supply input range: C0.4v to 44v, micropower 50 m a amplifier, rail-to-rail input and output, 200khz gbw lt2178/lt2179 dual/quad 17 m a max, single supply precision op amps so-8 and 14-lead standard pinout, 70 m v vos max, 85khz gbw typical applicatio n u

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