ANALOG DEVICES High-Speed (Ay-, = 10) Programmable Micropower Operational Amplifier OP-32 FEATURES * Programmable Supply Current ............ssec0 500nA to 2mA * Single Supply Operation ...........ccccccsesesesneees +3V to +30V * Dual Supply Operation ........ sees 1,5V to +15V * Low Input Offset Voltage ............csssccesssseseeseeeeseeseens 100L.V * Low Input Offset Voltage Drift ............ccssssseereeeeee 0.5pV/C * High Common-Mode Input Range V- to V+ (-1.5V) * High CMRR and PSAR ...... ccc ccsesseseeenennescensnseneanes 115dB * High Open-Loop Gain ....... ce csccsecensenereeneneereenes 2000V/mV * +30V Input Overvoltage Protection FASE oo. ceecccsteeerensseetsteseeseresnensrenenenoess 1V/us @ I, = 300nA * LM4250 Pinout * Compensated for Minimum Gain of 10 e Availabie in Die Form ORDERING INFORMATION ' T, = 25C PACKAGE OPERATING Vos MAX CERDIP PLASTIC TEMPERATURE (uV) 8-PIN 8-PIN RANGE 300 - OP32AZ* MIL 300 OP32EP OP32EZ IND 500 OP32FP OP32FZ IND 1000 OP32GP OP32GZ IND For devices processed in total compliance to MIL-STD-883, add /883 after part number. Consult factory for 883 data sheet. t Burn-in is available on commercial and industrial temperature range parts in CerDIP, plastic DIP, and TO-can packages. GENERAL DESCRIPTION The OP-32 is a high-speed, high-gain programmable opera- tional amplifier. Both offset voltage and offset current are low, and both are stable with changes in temperature, supply voltage, and set current. High CMRR and PSRR ensure SIMPLIFIED SCHEMATIC precision performance when the OP-32 is used with an unregulated battery or vehicular electrical system. The wide input voltage range, including the negative supply or ground, allows use in single-battery applications. The OP-32 is characterized over a wide supply range of +1.5V to +15V. This guarantees predictable performance with any commonly available supply. The ability to operate at relatively high speed with low power consumption makes this amplifier ideal for remote applica- tions where power is limited. The programmability allows each amplifier in a system to be set for the minimum power consumption necessary for each specific application. Programmability also makes it possible to adjust the band- width and phase shift. The OP-32 pinout is identical to the LM4250 and many other micropower operational amplifiers. This allows easy up- grading of system performance. PIN CONNECTIONS 8-PIN EPOXY DIP (P-Suffix) 8-PIN HERMETIC DIP (Z-Suffix) * DO NOT SHORT Iseq TO V- OR GROUND SEE APPLICATIONS INFORMATION Oo V+ O- OH |e a2 oo Saks 7X AN p-O OUTPUT AN JX o Yb [ fa be bf NULL NULLOP-32 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage 0.0.0... eccccccecssscesereesseeesceeecceeserceseaeeeaceusers +18V Differential Input Voltage ............ ee eeeeesseeteseeeseeseoreneeeeenes +30 Input Voltage ........... ee eceeseeeceeseeeeneteaeeneeeaeeeeee Supply Voltage Storage Temperature Range Z Package ...........cecceesscesessneeceeeseeeersenteesenees 65C to +150C P Package .......cccc cece cee seen senses seseeneees 55C to +125C Operating Temperature Range OP-32A 0... eeeeeeseeseeeneeen ee centres reasesssseasses ~55C to +125C OP-32E, F, G ose eee teeeeceeeteeeeeeessnnesessees 25C to +85C Lead Temperature Range (Soldering, 60 sec) .............. 300C Junction Temperature ............ cesses eteeeees 65C to +150C PACKAGE TYPE @,, (Note 2) B UNITS 8-Pin Hermetic DIP (2) 148 16 CAV 8-Pin Plastic DIP (P) 103 4 CWV NOTES: 1. Absolute maximum ratings apply to both DICE and packaged parts, unless otherwise noted. 2. @, is specified for worst case mounting conditions, i.e., 8 a '8 Specified for device in socket for CerDIP and P-DIP packages. ELECTRICAL CHARACTERISTICS at Vs = +1.5V to +15V, 15uA < Isy < 450A, Ta = +25C, unless otherwise noted. OP-32A/E OP-32F OP-32G PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Input Offset Voltage Vos 100 300 200 500 400 1000 uv Input Offset current los Vem =0 _ _ 2 _ _ 2 _ _ 3 nA Igy = 154A -- 3 65 - 65 75 - 5 10 | t Bi Note , Current ie Igy = 15044 2 35 224 35 30 50 nA Igy = 450A _ 60 90 _ 70 ~=100 _ 80 125 Input Voltage Range IVR Vg = +15V -15.0/13.5 _ -15.0/13.5 _ -15.0/13.5 _- - Vv Cc on-Mod Rejection Ratio CMRR Vs = 215V 100 8115 _ 95 110 _ 85 100 dB } ~15V < Voy < +13.5V (Note 2) Power Supply Vg = 1.5V to +15V; Rejection Ratio PSRR and V- = OV, _ 1 6 _- 3 12 _ 10 25 BV/V (Note 2) V+ = 3V to 30V. Large-Signal Vs = = 18, voite oe ocin Avo Ry, = 100k, Igy = 154A 1000 2000 _ 750 1500 _ 500 1000 - V/mV 9 Ry = 10k0), 150pA < Igy < 4502 Vg = +1.5V Ri. = 100k, Igy = 154A +0.8 +0.88 _ +0.8 +0.88 _ +0.75 +0.85 - Vv Output Voltage V R, = 10k, 150uA < Igy < 450uA . oO Swing Vg + 15V Ry, = 100k, Igy = 154A +14 +14.2 _ +14 +14.2 _ +13.8 414.2 _- Vv Ry, = 10k0, 150pA < Igy S 450A Gain-Bandwidth Igy = 15#A, Ry = 100kN 100 100 020 kHz Product Isy = 450A, Ry = 10k 4500 - 4500 _ 4500 _ Vg = +15V, Igy = 450pA, R _ 15 _ _ 1.5 _ _ 1.5 _ Slew Rate SR Ry = 10k V/us Vg = +15V, Iget= 1KA 6 1 - 6 19 - 6 21 Iget = 10pA 150 170 150 190 150 200 pA Supply Current _ _ _ No Load lev Ige7 = 30nA 450 525 450 600 450 650 (Note 3) Vg = 1.5V, Ige7 = 1HA 105 12.5 - an} 15 cd 11 18 Ige7 = 10nA 105 125 110 150 110 180 bA Ise7 = 30nA 350 400 350 450 350 500 NOTES: 1. 2. 3. lp and log are measured at Vey = 0. PSRR and CMRR measured with Vog unnulled and Ige7 held constant. The supply current (Igy) is dependent on the set current (Is_e7) and supply voltage as follows: sy ~10+ (V+) (V-) Iset 6 The range of Isy/Iser is approximately 10.5 to 15 over the specified operating range of V5 = +1.5V to Vg = +15V.OP-32 ELECTRICAL CHARACTERISTICS at V, = +1.5V to +15V, 15pA <I, < 450HA, 55C < T, < +125C, unless otherwise noted. OP-32A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Average Input Offset Voltage Drift (Note 1) TCVog Unnulled ~ 05 2.0 wveC Input Offset Voltage Vos - 175 400 pV Input Offset Current los Vom=0 - - 2 nA Average input Offset Current Drift TClos (Notes 1, 2) 7 1 10 parc Input Bias Current Ipy= 1SHA ~ 3 5 (Note 2) Ip Igy = 150pA - 20 35 nA ly = 450pnA - 60 90 Input Voltage Range IVR V, =t15V -15.0/13.5 - - Vv Common-Mode san ev 4185 Rejection Ratio CMRR cM . (Note 3) Iser = 10HA "10 _ dB Ise = 1HA 80 90 ~ Power Supply Vg =1.5V to t15V & Rejection Ratio PSRR V-=0V, - 2 10 pviV (Note 3) V+=3V to 30V(V,,,= 1.5V) V, =t15V Si s tere Sone Avo R, = 100k0, Igy = 15HA 200 400 - vimv 9 R, = 10kQ, 150HA <I. < 450nA 500 1000 - V,=41.5V R, = 100kQ, I. = 15pA L 'SY - Output Voltage Vv R, = 10kQ, 150pA <I, 5 450pA 0.65 40.75 V i oO Swing V, = 15V R, = 100kQ, i. = 15pA L "'SY 7 14. - R, = 10kQ, 150HA < Ig < 450pA #136 #140 V Vs =+15V loeg = THA - 16 18 lgeq = 1OHA - 160 180 pA Supply Current Igeq = S0pA - 450 550 No Load Isy (Note 4) V,=41 5V lgey = 1A - 12 14 leet = 10HA - 120 140 pA Ige7 = SOWA - 360 450 NOTES: 1. Sample tested. 2. Igand Igg are measured at Voy = 0. BURN-IN CIRCUIT* 3. PSRR and CMRR measured with Vog unnulled and Ige7 held constant. 4. The supply current (Igy) isdependent on the set current (Ige7) and supply voltage as follows: +18Vv Isy 40+ (V+) - (V-) IseT 2]. 7 OP-32 6 OUTPUT 3 4 8 -18V Other circuits may apply at ADIs discretion.OP-32 ELECTRICAL CHARACTERISTICS at Vs = 1.5V to +15V, 15yA < Igy < 450nA, -25C <= Ta = + 85C, unless otherwise noted. OP-32E OP-32F OP-32G PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Average Input Offset T _ . . - : . . . Voltage Drift (Note 1) 'Cos Unnutled 05 15 10 20 1530 ywec Input Offset Voltage Vos 100 400 200 600 500 1200 uv Input Offset Current log Vom = 9 _ _ 2 _ ad 2 _ _ 3 nA Average Input Offset TCl _ _ _ e Current Drift Clos (Notes 1, 2) 2 10 3 15 5 25 parc . Igy = 152A 3 5 - 5 75 _ 5 10 i tB t Note o Curren Ip Igy = 150uA 20 35 24 36 30 50 nA Igy = 450uA 60 9 70 100 80 125 Input Voltage Range IVR Vg = +15V -15.0/13.5 - -15.0/13.5 - -1.0/13.5 - V Common-Mode Vg = 15V & j i 110 _ 9 105 _ 8 1 - Rejection Ratio CMRR ~18V < Voy S +13.5V 95 10 0 0 00 dB (Note 3) Power Supply Vg =+1.5V to +15V & Rejection Ratio PSRR V-=0V, - 32 10 _ 10 32 _ 32 56 pV/V (Note 3) V+ =3V to 30V Large-Signal Vs = =18V, , x in Avo R, = 100k, Igy = 154A 750 1000 500 1000 400 1000 Wmv omage Sa R_ = 10k0, 150uA < Igy < 450nA 750 1000 500 1000 400 1000 Vg = +1.5V R, = 100kN, Igy = 15nA +0.70 0.75 _ +0.65 +0.75 _ +06 +07 _ v Output Voltage Vv R, = 10kN, 150pA S Igy S 450KA Swing Vg = 15V Ry, = 100k9, Igy = 152A #13.8 +14.1 _ +13.6 +141 _ +13.0 +14.0 _ v Rx. = 10k, 150uA < Igy S 450nA Vg = 15V, Igep = 1HA - 6 18 6 2 6 2 Iger = 102A 160 180 160 200 160 250 BA Supply Current _ _ _ No Load Isy Iser = 30nA 450 550 450 600 450 650 (Note 4) Vg = +1.5V, Iget = 1A - 2 14 - 2 17 12 2 get = 102A 120 140 120 170 120 200 nA Ise7 = 30pA 360 450 360 500 360 550 NOTES: 4. The supply current (Igy) is dependent on the set current (Igeq) and supply 1. Sample tested. voltage as follows: 2. |, and |, are measured at Vy, = 0. Igy 10 (V+)-(V-) 3. PSRR and CMRR measured with V,, unnulled and |... held constant. i at 5. SET DICE CHARACTERISTICS 1. BALANCE 2. INVERTING INPUT 3. NONINVERTING INPUT 4. V- 5. BALANCE 6. OUTPUT 7. V+ 8. sey DIE SIZE 0.070 X 0.050 inch, 3500 sq. mils (1.78 X 1.27 mm, 2.26 sq. mm) -4- Z4- Aye aOP-32 WAFER TEST LIMITS at V, = #1.5V to +15V, 15yA s |... < 450A, T, = 25C, unless otherwise noted. OP-32N OP-32G OP-32GR PARAMETER SYMBOL CONDITIONS LIMIT LIMIT LIMIT UNITS input Offset Voltage Vos 300 500 1000 pV MAX Input Offset Current los Vom =O 2 2 3 nA MAX Input Bias Current \ isy - teOuA : oe 0 (Note 1) 8 sy = 150p 35 35 50 nA MAX ley = 450nA 90 100 125 Input Voltage Range IVR Vg = #15V -15/13.5 -15/13.5 -15/13.5 V MIN Common-Mode V. = #15V Rejection Ratio CMRR Se. Vv 13.5V 100 95 85 dB MIN (Note 2) Nom = #0" Power Supply V, =21.5V to +15V & Rejection Rati PSRR S ejection Ratio Ss V_ = OV, V+ =3V to 30V 6 12 25 uV/V MAX (Note 2) V, = 2t5V Large-Signal s A R, = 100kQ, Io, = 15pA 1 Voltage Gain vo = 100 sy M 000 750 500 VimV MIN A, = 10k2, 150nA s Igy s 450pA 1000 750 500 Vg =+1.5V . RL = 100kQ, Isy = 15pA +0.8 +0.8 20.75 V MIN Output Voltage Vv R, = 100k22, 150pA <1, = 450nA Swi oO wing Vg = #15V R, = 100kQ, Isy = 15pA +14 214 213.8 V MIN R, = 10k, 150pA 1.) = 450nA Vg =#1-5V, Iggy = THA 12.5 15 18 ! = 10pA 12 1 Supply Current hee 30uA 400 a0 500 No Load Igy set = SH (Note 3) Vg = #15V, Ioe7 = THA 17 19 21 lger = 10nA 170 190 200 yA MAX Ioet = 30pA 525 600 650 NOTES: 1. 1, and1o, are measured at Vom =0. Igy 10 (V+)-(V-) 2. PSRR and CMRR measured with V,, unnulled and |,-, held constant. | =l0+ 6 SET 3. The supply current (ey) is dependent on the set current (tgeq) and supply voltage as follows: Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed for standard product dice. Consultt factory to negotiate specifications based on dice lot qualification through sample lot assembly and testing. TYPICAL DC PERFORMANCE CHARACTERISTICS OFFSET VOLTAGE vs TEMPERATURE 78 50 25 Vs = Igy = 150 TO 450: | +1.5V TO oo AVog luv) o A Pam Igy = 154A Vg = 11.5 TO +15 | 25 50 75 100 125 TEMPERATURE (C) OFFSET CURRENT (pA} OFFSET CURRENT vs TEMPERATURE Igy = 150uA Vg = 41.5V TO t15V -75 -50 -25 0 25 50 75 TEMPERATURE (C} 5- 100 125 BIAS CURRENT (nA), Igy = 15uA -60 BIAS CURRENT Igy = 154A Vg = #1.5V TO +15V -25 Q 25 50 75 TEMPERATURE (C) vs TEMPERATURE 100 BIAS CURRENT (nA), Igy = 150uA 0 125OP-32 TYPICAL DC PERFORMANCE CHARACTERISTICS OFFSET VOLTAGE OFFSET CURRENT BIAS CURRENT vs SUPPLY CURRENT vs SUPPLY CURRENT vs SUPPLY CURRENT 1000 Vg = 1.5V TO +15V Tp = 25C Ta = 25C z z x 100 = < g 2 = 5 Fe ra $ 3 f fr i 3 if 10 ic 4 5 ao NEGATIVE OFFSET 0 100 1000 10 100 1000 1 10 100 1000 SUPPLY CURRENT (A) SUPPLY CURRENT (uA) SUPPLY CURRENT (uA) MAXIMUM OUTPUT CURRENT BIAS CURRENT vs vs SUPPLY CURRENT AT OPEN-LOOP GAIN COMMON-MODE VOLTAGE Vs = + 15V, +5V AND +1.5V vs SUPPLY CURRENT 100 Ta = 25C : oe Igy = 450uA Ta = 425C z Igy = 15024 8 5 z 10 & & : 3 3 4 2 z 5 3 6 1 +15 +10 +5 0 - -10 0-15 1 10 100 1000 10 100 1000 COMMON-MODE VOLTAGE (VOLTS) SUPPLY CURRENT (uA) SUPPLY CURRENT (uA) SUPPLY CURRENT vs SET RESISTOR Vg =21 Ta= Aser TO SUPPLY CURRENT (nA) 10k 100k 1M 10M 100M SET RESISTOR (Q)OP-32 TYPICAL DC OPEN-LOOP INPUT-OUTPUT CHARACTERISTICS INPUT (uV) INPUT (uV) INPUT (uV) Igy = 1mA, R_ = 100kN. -20 -25 -20 -15 -10 -5 O 5 10 15 20 25 OUTPUT (VOLTS) | a 6 * 2 Isy = 100A, RL = -25 -20 -15 -10 -5 6 10 15 20 25 OUTPUT (VOLTS) Isy = 10uA, Ry = 100k0 -20 i ss 4 ri t Fs 0 OUTPUT {VOLTS) 5 10 15 20 25 -25 -20 -15 -10 -5 INPUT (xV) INPUT {nV} INPUT (nV) -25 -20 -25 -20 -25 -20 Igy = 1mA, Ry = 10k0 Isy = 1mA, RL = 2k0 > 2 b 2 a -1 -10 -5 0 5 10 15 20 25 -25 -20 -15 -10 - 0 5 10 15 20 25 OUTPUT (VOLTS) OUTPUT (VOLTS) Isy = 100uA, RL = 10k0 Isy = 100uA, RL = 2k0 > 7 bE > a < fs 3 -15 -10 -5 0 5 10 15 20 25 -25 -20 -15 -10 -5 0 6 10 15 20 25 OUTPUT (VOLTS) OUTPUT (VOLTS) Isy = 102A, Ry = 10k0 TEST CIRCUIT Vy ( Y ey = R2>R1,.R3 = 15 -10 vy -% 1 -15 -10 -5 0 5 10 15 20 25 Y= RF Ayoe VOUT OUTPUT (VOLTS)OP-32 TYPICAL AC PERFORMANCE CHARACTERISTICS GAIN-BANDWIDTH PRODUCT vs SUPPLY CURRENT 10M Vg = $15 _ Tg = 25C a = kb Yo > 1M a o ae a x - Q = Qa Z 100k ft @ 2 a a 10k 1 10 100 1000 SUPPLY CURRENT (uA) COMMON-MODE REJECTION vs FREQUENCY 140 NT | = Vg = 15V 120 | Ta = 25C Igy = 150uA 100 N S 80 oc = 60 Go nt 40 y N 20 0 10 100 1k 10k 100k IM FREQUENCY (Hz) TOTAL HARMONIC DISTORTION vs FREQUENCY 1.0 35 Ty = 25C 0.3 F- Igy = 1mA 30 = 01 OUTPUT 25 z SWING > Zi 0.03 20 4 6 = 0.01 15 ao 5 DISTORTION 0.003 10 0.001 5 0.0003 0 100 1k 10k 100k FREQUENCY (Hz) OUTPUT VOLTAGE SWING (dBV} SLEW RATE vs SUPPLY CURRENT 1 Vg= t15V Tp = 25C 3 3 0.4 wo e a o 2 w be @ =z 0.01 ws a Ww 0.001 1 10 100 1000 SUPPLY CURRENT (uA) COMMON-MODE REJECTION vs TEMPERATURE 150 Vg = +15V = 140 oO z 3 = 130 oO Ww a = 499 Igy = 1502 a 3 a 2 110 Igy = 154A ay s ~~ = 5 & 100 90 -75 -50 -25 0 25 50 75 100 125 TEMPERATURE (C) TOTAL HARMONIC DISTORTION vs FREQUENCY 1.0 35 Ta = 28C 0.3 F Igy = 10028 30 = 04 25 a 3 DISTORTION & 9,03 20 a z E 0.01 5 Oo a 5 0.003 10 OUTPUT SWING 0.001 5 0.0003 0 100 Tk 10k 100k FREQUENCY (Hz} OUTPUT VOLTAGE SWING (dBV) PSRR (dB) COMMON-MODE REJECTION (dB) jz} VOLTAGE NOISE (nv/ POWER SUPPLY REJECTION vs SUPPLY CURRENT OP32E AT Vg = 3V TO 30V Tat 25C OP32F AT Vg = 3V TO 30V OP32E AT Vg = 11 To OP32F AT Vg = 41.5 TO t15V OP32G AT Vg = 10 100 SUPPLY CURRENT (yA) 1000 COMMON-MODE REJECTION vs SUPPLY CURRENT 10 100 1000 SUPPLY CURRENT (pA) VOLTAGE NOISE vs FREQUENCY 0.1 1 10 100 FREQUENCY (Hz)TYPICAL AC PERFORMANCE CHARACTERISTICS SMALL-SIGNAL TRANSIENT RESPONSE vs SUPPLY CURRENT Isy = 1.5uA Isy = 7.5yA Isy = 15nA Isy = 150uA Igy = 450uA Isy = 750uA Isy=1.5mA TEST CIRCUIT V.1k&2 >-O OUTPUT > 100k 22OP-32 TYPICAL AC PERFORMANCE CHARACTERISTICS LARGE-SIGNAL TRANSIENT RESPONSE vs SUPPLY CURRENT Isy = 7.5uA Rez = 110k2, Re = IMO, R, = OPEN Req = 11k, Rez = 100k2, Ry = IM Req = 11k, Reg = 100k2, Ry = IMO Isy = 150uA Isy = 450A Isy = 750A ov MY _ Es Req = 1.1k2, Reg = 10k, Ry = 100k Rpq = 11k, Rpg = 10k2, Ry = 100k Req = 1.-1k2, Reg = 10k2, Ry = 1002 Isy=1.5mA TEST CIRCUIT Req Req = VK, Rpg = 10k, Ry = 100k2 ey -11-OP-32 APPLICATIONS INFORMATION CURRENT SETTING CIRCUITS SETTING SUPPLY CURRENT The op amp power supply current is determined by the current flowing out of pin 8. Pin 8 is at the V+ voltage less two diode drops, which is approximately V+ minus 1.1V. Do not connect pin 8 to ground or V- without a set resistor in series orexcessive supply current will be drawn which may damage the OP-32. The set resistor value is selected to make the power supply current optimum for the specific application. Adjusting the OP-32 power supply current determines the slew-rate, bandwidth, and the output current limits (see Performance Characteristics). The supply current is nominally 15 times the set current and the set resistor value is calculated from: V, (Vsuppcy 1.1V) set ~ ian 'pss 'ser Rs= , where Igy = 15 Iset (a) I seT (See graph below) Note that the set resistor can go to either negative supply or to ground. If the set resistor goes to negative supply, then Vsupecy = (V+) - (V-). Fora single-supply circuit, Vsuppty is simply (V+). If the supply voltage varies widely, set current can be stabilized with circuits (a), (b), or (c). The relationship between supply voltage, supply current and set current can be approximated by: - 2x Isy ~10+ WH) = (V=) (Ta = 25C) 2N930A IseT 6 The ratio at increases with temperature by approximately SET 0.05%/ C. (b) SUPPLY CURRENT vs TEMPERATURE = WA 2N930A SUPPLY CURRENT (uA), Igey SUPPLY CURRENT (nA), Iggy = 1024 4 lz 'seT 1 9 90 -75 -50 -25 Q 2 50 75 100 125 TEMPERATURE (C) (c) INPUT BIAS CURRENT Input bias current varies directly with set current. The set current required for a given supply current ranges from Isy/10.5 at + 1.5V supply voltage to Isy/15 at + 15V. Therefore, Ig will be highest at the minimum supply voltage condition of +1.5V (or 3V) for any given supply current. -12-OP-32 OFFSET NULLING CIRCUIT BATTERY-POWERED, GAIN-OF-100 AMPLIFIER OUTPUT Figure 1 OFFSET VOLTAGE ADJUSTMENT The offset voltage can be trimmed to zero using a 100k. potentiometer (see offset nulling circuit). Adjusting the pot wiper towards pin 5 causes the output to go positive. Adjustment range is approximately +5mV at Vg= + 15V. The Vos adjust range is proportional to supply voltage. Resolu- tion of the nulling can be increased by using a smaller potin conjunction with fixed resistors. If power supply voltages vary widely and the set current is established bya resistor, the op amp supply currents will vary in proportion to the supply voltage changes. Vos will remain almost constant with supply current changes if the null pins (1 and 5) are not used. If a Vog adjust pot is used, current variations may flow through the offset pot causing an apparent Vos change. If a Vos adjust pot is used in combina- tion with widely-varying supply voltages, a set-current stabilizer circuit as shown in (a), (b), or (c) is recommended. APPLICATIONS EXAMPLE BATTERY-POWERED, GAIN-OF-100 AMPLIFIER The simple noninverting amplifier circuit shown in Figure 1 provides an accurate gain-of-100 while operating from a pair of 9V batteries. The circuit requires only 154A of supply current. Slew-rate is approximately 0.06V/ysec and output swing is +8V. A value of 500k was chosen for Ro. For a gain of 100, R; is calculated as: Avo = 1+ 22 100 = 1 + 200k Ry 2 Ry =5.05k0 2-632 OPERATIONAL AMPLIFIERS Using an OP-32B/F, we can expect an Ig+ Ios/2 of less than 8.5nA when operating at Isy of 15uA, so the input offset caused by IgR; will be negligible (8.5nA X 5.05kN ~ 43uV). The set resistor Rg needed for a supply current of 15uA is calculated from: Re = Vsuppty71.1V_ 18V-1.1V Ss Igy/15 1A . Rg = 16.9M2 Offset voltage adjustment is optional. An OP-32B/F has maximum input offset voltage of 500uV which would cause an output offset voltage of 50mV. Drift over temperature is very low, typically less than 1.0uV/ C, and is guaranteed to be less than 2.0uV/ C. PSRR is also low, only 6uV/V, so battery voltage change has negligible effect on offset. Most micropower programmable op amps lose open-loop gain and CMRR at low supply currents. The OP-32 design overcomes these limitations so accuracy is maintained at supply currents of only a few microamps. The OP-32B/F used in this example has a minimum open-loop gain of over 117dB. Gain error due to finite open-loop gain will be less than 100/750,000, which is only 133 PPM. CMRR will typically be 110dB, an error of 3PPM. Gain accuracy of the circuit is almost entirely dependent on the accuracy of the R;/Ro2 ratio; the op amp contributes less than 0.015% gain error. Considering all error sources, this simple <100 battery- powered circuit using an OP-32B/F is capable of achieving excellent accuracy. Without external adjustments of any kind, output offset will be less than 54mV and gain accuracy will be better than +0.015% (exclusive of R2/R, error). Gain linearity, slew-rate symmetry, and stability over temperature are all excellent with the OP-32, making circuit performance very predictable. REV. C