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1 LT1638/lt1639 1.2mhz, 0.4v/ m s over-the-top tm micropower rail-to-rail input and output op amps features descriptio n u n operates with inputs above v + n rail-to-rail input and output n low power: 230 m a per amplifier max n gain bandwidth product: 1.2mhz n slew rate: 0.4v/ m s n high output current: 25ma min n specified on 3v, 5v and 15v supplies n reverse battery protection to 18v n no supply sequencing problems n high voltage gain: 1500v/mv n single supply input range: C 0.4v to 44v n high cmrr: 98db n no phase reversal applicatio n s u n battery- or solar-powered systems portable instrumentation sensor conditioning n supply current sensing n battery monitoring n micropower active filters n 4ma to 20ma transmitters v cc v cc v1 v2 v0 + a 1/2 LT1638 + b 1/2 LT1638 v cc 1m 1m 1m 10k 10k v cc = 5v, v cm = 0v to 44v, t pd = 27 m s 1638/39 ta01 1m over-the-top comparator with 100mv hysteresis centered at 0mv typical applicatio n u output voltage vs input voltage 5v 0v the lt ? 1638 is a low power dual rail-to-rail input and output operational amplifier available in the standard 8-pin pdip and so packages as well as the 8-lead msop package. the lt1639 is a low power quad rail-to-rail input and output operational amplifier offered on the standard 14-pin pdip and surface mount packages. the LT1638/lt1639 op amps operate on all single and split supplies with a total voltage of 2.5v to 44v drawing only 170 m a of quiescent current per amplifier. these amplifiers are reverse battery protected and draw no current for reverse supply up to 18v. the input range of the LT1638/lt1639 includes both supplies, and a unique feature of this device is its capability to operate over the top with either or both of its inputs above v + . the inputs handle 44v, both differential and common mode, independent of supply voltage. the input stage incorporates phase reversal protection to prevent false outputs from occurring even when the inputs are 22v below the negative supply. protective resistors are included in the input leads so that current does not become excessive when the inputs are forced below the negative supply. the LT1638/lt1639 can drive loads up to 25ma and still maintain rail-to-rail capability. the op amps are unity-gain stable and drive all capacitive loads up to 1000pf when optional output compensation is used. , ltc and lt are registered trademarks of linear technology corporation. over-the-top is a trademark of linear technology corporation. 1638/39 ta02
2 LT1638/lt1639 absolute m axi m u m ratings w ww u specified temperature range (note 3) .. C 40 c to 85 c junction temperature ........................................... 150 c storage temperature range ................. C 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c total supply voltage (v + to v C ) .............................. 44v input differential voltage ......................................... 44v input current ...................................................... 25ma output short-circuit duration (note 2) .........continuous operating temperature range ................ C 40 c to 85 c package/order i n for m atio n w u u order part number order part number LT1638cms8 LT1638cs8 LT1638is8 LT1638cn8 LT1638in8 ms8 part marking s8 part marking 1638i 1638 top view s package 14-lead plastic so n package 14-lead pdip 1 2 3 4 5 6 7 14 13 12 11 10 9 8 a b c 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 d order part number lt1639cs lt1639is lt1639cn lt1639in t jmax = 150 c, q ja = 110 c/ w (n) t jmax = 150 c, q ja = 150 c/ w (s) 1 2 3 4 out a ?n a +in a v 8 7 6 5 v+ out b ?n b +in b top view ms8 package 8-lead plastic msop t jmax = 150 c, q ja = 250 c/ w (ms8) 1 2 3 4 8 7 6 5 top view n8 package 8-lead pdip s8 package 8-lead plastic so v + out b in b +in b a b out a in a +in a v t jmax = 150 c, q ja = 130 c/ w (n8) t jmax = 150 c, q ja = 190 c/ w (s8) ltcy symbol parameter conditions min typ max units v os input offset voltage LT1638 n, s packages 200 600 m v 0 c t a 70 c l 850 m v C40 c t a 85 c l 950 m v lt1639 n, s packages 300 700 m v 0 c t a 70 c l 950 m v C40 c t a 85 c l 1050 m v LT1638c ms8 package 350 900 m v 0 c t a 70 c l 1150 m v C40 c t a 85 c l 1250 m v input offset voltage drift LT1638/lt1639 n, s packages l 26 m v/ c (note 7) LT1638cms8 l 2.5 7 m v/ c i os input offset current l 16 na v cm = 44v (note 4) l 2.5 m a v s = 3v, 0v; v s = 5v, 0v; v cm = v out = half supply, t a = 25 c, unless otherwise noted. (note 3) consult factory for military grade parts. electrical characteristics (note 1)
3 LT1638/lt1639 electrical characteristics symbol parameter conditions min typ max units i b input bias current l 20 50 na v cm = 44v (note 4) l 830 m a v s = 0v 0.1 na input noise voltage 0.1hz to 10hz 1 m v p-p e n input noise voltage density f = 1khz 20 nv/ ? hz i n input noise current density f = 1khz 0.3 pa/ ? hz r in input resistance differential 1 2.5 m w common mode, v cm = 0v to 44v 1.4 5.5 m w c in input capacitance 5pf input voltage range l 044v cmrr common mode rejection ratio v cm = 0v to v cc C 1v l 88 98 db v cm = 0v to 44v (note 8) l 80 88 db a vol large-signal voltage gain v s = 3v, v o = 500mv to 2.5v, r l = 10k 200 1500 v/mv 0 c t a 70 c l 133 v/mv C40 c t a 85 c l 100 v/mv v s = 5v, v o = 500mv to 4.5v, r l = 10k 400 1500 v/mv 0 c t a 70 c l 250 v/mv C40 c t a 85 c l 200 v/mv v ol output voltage swing low v s = 3v, no load l 38 mv v s = 3v, i sink = 5ma l 250 450 mv v s = 5v, no load l 38 mv v s = 5v, i sink = 10ma l 500 700 mv v oh output voltage swing high v s = 3v, no load l 2.94 2.98 v v s = 3v, i source = 5ma l 2.25 2.40 v v s = 5v, no load l 4.94 4.98 v v s = 5v, i source = 10ma l 3.8 4.0 v i sc short-circuit current (note 2) v s = 3v, short to gnd 10 15 ma v s = 3v, short to v cc 15 25 ma v s = 5v, short to gnd 15 20 ma v s = 5v, short to v cc 15 25 ma psrr power supply rejection ratio v s = 3v to 12.5v, v cm = v o = 1v l 90 100 db reverse supply voltage i s = C 100 m a per amplifier l 18 27 v minimum operating supply voltage l 2.4 2.7 v i s supply current per amplifier 170 230 m a (note 5) l 275 m a gbw gain bandwidth product f = 5khz 650 1075 khz (note 4) 0 c t a 70 c l 550 khz C40 c t a 85 c l 500 khz sr slew rate a v = C 1, r l = 0.210 0.38 v/ m s (note 6) 0 c t a 70 c l 0.185 v/ m s C40 c t a 85 c l 0.170 v/ m s v s = 3v, 0v; v s = 5v, 0v; v cm = v out = half supply, t a = 25 c, unless otherwise noted. (note 3)
4 LT1638/lt1639 electrical characteristics v s = 15v, v cm = 0v, v out = 0v, t a = 25 c, unless otherwise noted. (note 3) symbol parameter conditions min typ max units v os input offset voltage LT1638 n, s packages 250 800 m v 0 c t a 70 c l 1000 m v C40 c t a 85 c l 1100 m v lt1639 n, s packages 350 900 m v 0 c t a 70 c l 1100 m v C40 c t a 85 c l 1200 m v LT1638c ms8 package 400 1050 m v 0 c t a 70 c l 1250 m v C40 c t a 85 c l 1350 m v input offset voltage drift LT1638/lt1639 n, s packages l 26 m v/ c (note 7) LT1638cms8 l 2.5 7 m v/ c i os input offset current l 16 na i b input bias current l 20 50 na input noise voltage 0.1hz to 10hz 1 m v p-p e n input noise voltage density f = 1khz 20 nv/ ? hz i n input noise current density f = 1khz 0.3 pa/ ? hz r in input resistance differential 1 2.5 m w common mode, v cm = C 15v to 14v 500 m w c in input capacitance 4.5 pf input voltage range l C15 29 v cmrr common mode rejection ratio v cm = C15v to 29v l 80 88 db a vol large-signal voltage gain v o = 14v, r l = 10k 200 500 v/mv 0 c t a 70 c l 125 v/mv C40 c t a 85 c l 100 v/mv v o output voltage swing no load l 14.9 14.95 v i out = 10ma l 13.7 14.0 v i sc short-circuit current (note 2) short to gnd 25 40 ma 0 c t a 70 c l 20 ma C40 c t a 85 c l 15 ma psrr power supply rejection ratio v s = 1.5v to 22v l 90 100 db i s supply current per amplifier 205 280 m a l 350 m a gbw gain bandwidth product f = 5khz 750 1200 khz 0 c t a 70 c l 650 khz C40 c t a 85 c l 600 khz sr slew rate a v = C 1, r l = , v o = 10v, 0.225 0.4 v/ m s 0 c t a 70 c l 0.2 v/ m s C40 c t a 85 c l 0.18 v/ m s the l denotes specifications which apply over the full specified temperature range. note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: a heat sink may be required to keep the junction temperature below absolute maximum. this depends on the power supply voltage and how many amplifiers are shorted. note 3: the LT1638c/lt1639c are guaranteed to meet 0 c to 70 c specifications and are designed, characterized and expected to meet the extended temperature limits, but are not tested at C 40 c and 85 c. the LT1638i/lt1639i are guaranteed to meet the extended temperature limits. note 4: v s = 5v limits are guaranteed by correlation to v s = 3v and v s = 15v tests. note 5: v s = 3v limits are guaranteed by correlation to v s = 5v and v s = 15v tests. note 6: guaranteed by correlation to slew rate at v s = 15v and gbw at v s = 3v and v s = 15v tests. note 7: this parameter is not 100% tested. note 8: the spec implies a typical offset voltage at v cm = 44 of 2mv and a maximum offset voltage at v cm = 44 of 5mv.
5 LT1638/lt1639 typical perfor m a n ce characteristics u w minimum supply voltage input bias current vs common mode voltage output saturation voltage vs load current (output high) 0.1hz to 10hz noise voltage noise voltage density vs frequency supply voltage (v) 0 supply current per amplifier ( m a) 10 20 25 45 1638/39 g01 300 280 260 240 220 200 180 160 140 120 100 515 30 35 40 t a = 125 c t a = 25 c t a = 55 c supply current vs supply voltage total supply voltage (v) 0 change in input offset voltage ( m v) 200 400 4 1638/39 g02 0 200 100 300 100 300 400 1 2 3 5 t a = 125 c t a = ?5 c t a = 25 c common mode voltage (v) 4.0 input bias current (na) 10000 8000 6000 60 40 20 0 ?0 ?0 5.6 1638/39 g03 4.4 4.8 5.2 44 t a = 125 c t a = ?5 c t a = 25 c v s = 5v, 0v frequency (hz) 1 input noise voltage density (nv/ ? hz) 10 100 1k 1638/39 g09 70 60 50 40 30 20 10 0 time (sec) 013579 noise voltage (400nv/div) 2468 1638/39 g07 10 v s = 2.5 frequency (hz) 1 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 10 100 1k 1638/39 g08 input noise current density (pa/ hz) sourcing load current (ma) 0.001 0.01 output saturation voltage (v) 0.1 1 0.01 0.1 1 10 1638/39 g04 v s = 2.5v v od = 30mv t a = 125 c t a = 55 c t a = 25 c sinking load current (ma) 0.001 0.001 output saturation voltage (v) 0.1 0.01 1 0.01 0.1 1 10 1638/39 g05 v s = 2.5v v od = 30mv t a = 125 c t a = 55 c t a = 25 c input overdrive (mv) 10 output saturation voltage (mv) 30 100 1638/39 g06 1 10 20 100 90 80 70 60 50 40 0 v s = 2.5v no load output high output low output saturation voltage vs input overdrive output saturation voltage vs load current (output low) input noise current density vs frequency
6 LT1638/lt1639 typical perfor m a n ce characteristics u w psrr vs frequency output impedance vs frequency load resistance (k w ) 1 gain bandwidth product (khz) phase margin (deg) 1500 1400 1300 1200 1100 1000 900 800 10 100 1638/39 g17 60 50 40 30 20 10 0 ?0 v s = 2.5v a v = ? r f = r g = 100k f = 1khz phase margin gain bandwidth product gain and phase shift vs frequency frequency (khz) 1 10 gain (db) phase shift (deg) 20 30 40 50 10 100 1000 1638/39 g12 0 ?0 ?0 80 60 70 40 50 60 70 80 30 20 10 0 90 100 v s = 2.5v phase gain frequency (khz) power supply rejection ratio (db) 90 80 70 60 50 40 30 20 10 0 ?0 1 10 100 1000 1638/39 g16 v s = 2.5v positive supply negative supply temperature ( c) ?0 slew rate (v/ m s) 0 50 75 1638/39 g14 ?5 25 100 125 rising, v s = 15v rising, v s = 2.5v falling, v s = 2.5v 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 falling, v s = 15v slew rate vs temperature gain bandwidth product and phase margin vs supply voltage total supply voltage (v) 0 1000 gain bandwidth product (khz) 1200 1500 10 20 25 45 1638/39 g15 1100 1400 1300 phase margin (deg) 10 30 60 20 50 40 515 30 35 40 phase margin gain bandwidth gain bandwidth product and phase margin vs load resistance frequency (khz) common mode rejection ratio (db) 120 110 100 90 80 70 60 50 40 30 20 1 10 100 1000 1638/39 g18 v s = 15v cmrr vs frequency frequency (khz) 0.1 channel separation (db) 130 120 110 100 90 80 70 60 1 10 100 1638/39 g19 v s = 15v channel separation vs frequency frequency (khz) output impedance ( w ) 10k 1k 100 10 1 0.1 0.1 10 100 1000 1638/39 g20 1 a v = 1 a v = 100 a v = 10 v s = 2.5v temperature ( c) ?0 gain bandwidth product (khz) 1500 1400 1300 1200 1100 1000 900 800 0 50 75 1638/39 g13 ?5 25 100 125 v s = 15v v s = 2.5v f = 1khz gain bandwith product vs temperature
7 LT1638/lt1639 typical perfor m a n ce characteristics u w settling time to 0.1% vs output step capacitive load handling, overshoot vs capacitive load settling time ( m s) 0 ?0 output step (v) ? ? ? 0 10 4 10 20 25 1638/39 g21 ? 6 8 2 515 30 35 a v = ? a v = ? a v = 1 a v = 1 v s = 15v undistorted output swing vs frequency total harmonic distortion + noise vs frequency total harmonic distortion + noise vs load resistance total harmonic distortion + noise vs output voltage open-loop gain large-signal response small-signal response 1638/39 g28 1638/39 g29 v s = 15v a v = 1 v s = 15v a v = 1 c l = 15pf output voltage (5v/div) change in input offset voltage (50 m v/div) 1638/39 g27 10v 20v 0v 10v 20v r l = 2k v s = 15v r l = 10k r l = 50k capacitive load (pf) overshoot (%) 100 90 80 70 60 50 40 30 20 10 0 10 100 1000 10000 1638/39 g22 a v = 1 a v = 5 a v = 10 v s = 5v, 0v v cm = 2.5v i source = 150 m a frequency (khz) 0.1 output swing (v p-p ) 1 10 100 1638/39 g23 35 30 25 20 15 10 5 0 distortion 1% r l = 20k v s = 2.5v v s = 15v frequency (hz) thd + noise (%) 0.01 1 10 100 1638/39 g24 0.1 10 1 0.1 0.01 0.001 v s = 3v, 0v v out = 2v p-p v cm = 1.2v r l = 20k a v = 1 a v = 1 load resistance to ground (k ) 0.01 thd + noise (%) 0.1 1 10 0.1 10 100 1638/39 g25 0.001 1 v s = 3v total a v = 1 v in = 2v p-p at 1khz v s = 1.5v v in = 1v v s = 3v, 0v v in = 0.5v to 2.5v v s = 3v, 0v v in = 0.2v to 2.2v output voltage (v p-p ) thd + noise (%) 10 1 0.1 0.01 0.001 023 1638/39 g26 1 r l = 10k, f = 1khz v cm = half supply a v = 1, v s = 1.5v a v = 1, v s = 3v, 0v a v = 1, v s = 1.5v a v = 1, v s = 3v, 0v
8 LT1638/lt1639 applicatio n s i n for m atio n wu u u supply voltage the positive supply pin of the LT1638/lt1639 should be bypassed with a small capacitor (typically 0.1 m f) within an inch of the pin. when driving heavy loads an additional 4.7 m f electrolytic capacitor should be used. when using split supplies, the same is true for the negative supply pin. the LT1638/lt1639 are protected against reverse battery voltages up to 18v. in the event a reverse battery condition occurs, the supply current is less than 1na. the LT1638/lt1639 can be shut down by removing v + . in this condition the input bias current is less than 0.1na, even if the inputs are 44v above the negative supply. at temperatures greater than 70 c, when operating the LT1638/lt1639 on total supplies of 10v or more, the supply must not be brought up faster than 1v/ m s. increas- ing the bypass capacitor and/or adding a small resistor in series with the supply will limit the rise time. inputs the LT1638/lt1639 have two input stages, npn and pnp (see the simplified schematic), resulting in three distinct operating regions as shown in the input bias current vs common mode typical performance curve. for input voltages about 0.8v or more below v + , the pnp input stage is active and the input bias current is typically C 20na. when the input common mode voltage is within 0.5v of the positive rail, the npn stage is operating and the input bias current is typically 40na. increases in tempera- ture will cause the voltage at which operation switches from the pnp input stage to the npn input stage to move towards v + . the input offset voltage of the npn stage is untrimmed and is typically 600 m v. a schottky diode in the collector of each npn transistor allow the LT1638/lt1639 to operate over the top, with either or both of its inputs above v + . at about 0.3v above v + the npn input transistor is fully saturated and the input bias current is typically 8 m a at room temperature. the input offset voltage is typically 2mv when operating above v + . the LT1638/lt1639 will operate with its inputs 44v above v C regardless of v + . the inputs are protected against excursions as much as 22v below v C by an internal 1k resistor in series with each input and a diode from the input to the negative supply. the input stage of the LT1638/lt1639 incorporates phase reversal protection to prevent the output from phase reversing for inputs up to 22v below v C . there are no clamping diodes between the inputs and the maximum differential input voltage is 44v. output the output of the LT1638/lt1639 can swing within 20mv of the positive rail with no load, and within 3mv of the negative rail with no load. when monitoring voltages within 20mv of the positive rail or within 3mv of the negative rail, gain should be taken to keep the output from clipping. the LT1638/lt1639 are capable of sinking and sourcing over 40ma on 15v supplies; sourcing current capability is reduced to 20ma at 5v total supplies as noted in the electrical characteristics. the LT1638/lt1639 are internally compensated to drive at least 200pf of capacitance under any output loading conditions. a 0.22 m f capacitor in series with a 150 w resistor between the output and ground will compensate these amplifiers for larger capacitive loads, up to 1000pf, at all output currents. distortion there are two main contributors of distortion in op amps: output crossover distortion as the output transitions from sourcing to sinking current and distortion caused by non- linear common mode rejection. if the op amp is operating inverting there is no common mode induced distortion. if the op amp is operating in the pnp input stage (input is not within 0.8v of v + ), the cmrr is very good, typically 98db. when the LT1638 switches between input stages there is significant nonlinearity in the cmrr. lower load resis- tance increases the output crossover distortion, but has no effect on the input stage transition distortion. for low- est distortion the LT1638/lt1639 should be operated single supply, with the output always sourcing current and with the input voltage swing between ground and (v + C 0.8v). see the typical performance characteristics curves.
9 LT1638/lt1639 applicatio n s i n for m atio n wu u u typical applicatio n s u with 1.2mhz bandwidth, over-the-top capability, re- verse-battery protection and rail-to-rail input and output features, the LT1638/lt1639 are ideal candidates for general purpose applications. the lowpass slope limiting filter in figure 1 limits the maximum dv/dt (not frequency) that it passes. when the input signal differs from the output by one forward diode drop, d1 or d2 will turn on. with a diode on, the voltage across r2 will be constant and a fixed current, v diode /r2, will flow through capacitor c1, charging it linearly instead of exponentially. the maximum slope that the circuit will pass is equal to v diode divided by (r2)(c1). no matter how fast the input changes the output will never change any faster than the dv/dt set by the diodes and (r2)(c). + + 1/4 lt1639 + 1/4 lt1639 1/4 lt1639 d1 d2 v cc c1 v out v ee v in r5 100k r6 100k 1638/39 f02 lt1634-1.2v r3 100k r4 100k r2 r1 1k d3 d4 lt1634-1.2v for r2 = 50k, c1 = 500pf, maximum slope = 0.048v/ m s v out = d dt 1.2v (r2)(c1) gain the open-loop gain is almost independent of load when the output is sourcing current. this optimizes perfor- mance in single supply applications where the load is returned to ground. the typical performance curve of open-loop gain for various loads shows the details. v out v in response of slope limiting filter figure 2. lowpass slope limiting filter with 0tc + 1/2 LT1638 c1 v out 1638/39 f01 r2 d2 d1 r1 v in for r1 = 10k, r2 = 100k, c1 = 1000pf v out(max) = d dt v d (r2)(c1) v out(max) = 0.006v/ m s d dt a modification of this application is shown in figure 2 using references instead of diodes to set the maximum slope. by using references, the slope is independent of temperature. a scope photo shows a 1v p-p , 2khz input signal with a 2v pulse added to the sine wave; the circuit passes the 2khz signal but limits the slope of the pulse. the application in figure 3 utilizes the over-the-top capabilities of the LT1638. the 0.2 w resistor senses the load current while the op amp and npn transistor form a closed loop making the collector current of q1 figure 1. lowpass slope limiting filter 1638/39 ta02
10 LT1638/lt1639 typical applicatio n s u propor tional to the load current. as a convenient monitor, the 2k load resistor converts the current into a voltage. the positive supply rail, v + , is not limited to the 5v supply of the op amp and could be as high as 44v. the figure 4 application uses the LT1638 in conjunction with the lt1634 micropower shunt reference. the supply current of the op amp also biases the reference. the drop across resistor r1 is fixed at 1.2v generating an output current equal to 1.2v/r1. + 1/2 LT1638 5v v + 200 w 200 w 0.2 w 2k 0v to 4.3v 1638/39 f03 v out = (2 w )(i load ) q1 2n3904 load i load figure 4. current source figure 3. positive supply rail current sense si plified sche atic ww q10 d5 q9 q1 q7 r2 1k r3 1k r4 8k q8 q5 ?n +in q11 q12 d4 one amplifier d2 q2 d1 q6 q13 q14 r1 6k r5 8k q4 10 m a + q15 q19 d3 q3 q16 q18 q22 v + q17 q20 q21 out v 1638/39 ss package descriptio n u dimensions in inches (millimeters) unless otherwise noted. ms8 package 8-lead plastic msop (ltc dwg # 05-08-1660) msop (ms8) 1197 * dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.006" (0.152mm) per side ** dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.006" ( 0.152mm ) per side 0.021 0.006 (0.53 0.015) 0 ?6 typ seating plane 0.007 (0.18) 0.040 0.006 (1.02 0.15) 0.012 (0.30) ref 0.006 0.004 (0.15 0.102) 0.034 0.004 (0.86 0.102) 0.0256 (0.65) typ 12 3 4 0.192 0.004 (4.88 0.10) 8 7 6 5 0.118 0.004* (3.00 0.102) 0.118 0.004** (3.00 0.102) + 1/2 LT1638 r1 1.2v r1 i out = lt1634-1.2 i out 1638/39 f04 v cc v cc
11 LT1638/lt1639 package descriptio n u dimensions in inches (millimeters) unless otherwise noted. 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. n8 package 8-lead pdip (narrow 0.300) (ltc dwg # 05-08-1510) n8 1197 0.100 0.010 (2.540 0.254) 0.065 (1.651) typ 0.045 ?0.065 (1.143 ?1.651) 0.130 0.005 (3.302 0.127) 0.020 (0.508) min 0.018 0.003 (0.457 0.076) 0.125 (3.175) min 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 () 12 3 4 87 6 5 0.255 0.015* (6.477 0.381) 0.400* (10.160) max *these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed 0.010 inch (0.254mm) 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 0996 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 * ** s8 package 8-lead plastic small outline (narrow 0.150) (ltc dwg # 05-08-1610) s14 0695 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) 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) n14 1197 0.255 0.015* (6.477 0.381) 0.770* (19.558) max 3 1 2 4 5 6 7 8 9 10 11 12 13 14 0.020 (0.508) min 0.125 (3.175) min 0.130 0.005 (3.302 0.127) 0.045 ?0.065 (1.143 ?1.651) 0.065 (1.651) typ 0.018 0.003 (0.457 0.076) 0.100 0.010 (2.540 0.254) 0.005 (0.125) min 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 14-lead pdip (narrow 0.300) (ltc dwg # 05-08-1510)
12 LT1638/lt1639 16389fs, sn16389 lt/tp 1098 4k ? printed in usa ? 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 the battery monitor in figure 5 also demonstrates the LT1638s ability to operate with its inputs above the positive rail. in this application, a conventional amplifier would be limited to a battery voltage between 5v and ground, but the LT1638 can handle battery voltages as high as 44v. when the battery is charging, amp b senses the voltage drop across r s . the output of amp b causes q2 to drain sufficient current through r b to balance the input of amp b. likewise, amp a and q1 form a closed r a , 2k q2 2n3904 s1 s1 = open, gain = 1 s1 = closed, gain = 10 r a = r b v s = 5v, 0v 10k 90.9k v out logic 1638/39 f05 logic high (5v) = charging logic low (0v) = discharging r g 10k q1 2n3904 r s , 0.2 w charger voltage r a ', 2k r b ' , 2k r b , 2k v batt = 12v i batt + load v out (r s )(r g /r a )(gain) v out gain i batt = = amps + a 1/4 lt1639 + b 1/4 lt1639 + c 1/4 lt1639 + d 1/4 lt1639 figure 5. battery monitor part number description comments lt1078/lt1079 dual/quad 55 m a max, single supply, precision op amps input/output common mode includes ground, 70 m v v os(max) lt2078/lt2079 and 2.5 m v/ c drift (max), 200khz gbw, 0.07v/ m s slew rate lt1178/lt1179 dual/quad 17 m a max, single supply, precison op amps input/output common mode includes ground, 70 m v v os(max) lt2178/lt2179 and 4 m v/ c drift (max), 85khz gbw, 0.04v/ m s slew rate lt1366/lt1367 dual/quad precision, rail-to-rail input and output op amps 475 m v v os(max) , 500v/mv a vol(min) , 400khz gbw lt1490/lt1491 dual/quad over-the-top micropower, rail-to-rail input and single supply input range: C 0.4v to 44v, micropower 50 m a output op amps per amplifier, rail-to-rail input and output, 200khz gbw lt1636 single over-the-top micropower rail-to-rail input and output 55 m a supply current, v cm extends 44v above v ee , op amp independent of v cc ; msop package, shutdown function related parts loop when the battery is discharging. the current through q1 or q2 is proportional to the current in r s and this current flows into r g and is converted into a voltage. amp d buffers and amplifies the voltage across r g . amp c compares the output of amp a and amp b to determine the polarity of current through r s . the scale factor for v out with s1 open is 1v/a. with s1 closed the scale factor is 1v/100ma and currents as low as 500 m a can be measured.

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