ANALOG DEVICES Low Noise, Precision, High Speed Operational Amplifier (Ay, = 5) OP-37 FEATURES @ Low Noise .................. 80nV p-p (0.1Hz to 10Hz) eee e eee ce eee een ees 3nV/V Hz at 1kHz Low Drift .... 0... .. cee cc eee ere eens 0.2nV/C High Speed .....................0.66. 17V/yus Slew Rate chee ee eee e neces 63MHz Gain Bandwidth Low Input Offset Voltage 10nV Excellent CMRR ... 126dB (Common-Voltage of +11V) High Open-Loop Gain 1.8 Million Replaces 725, OP-05, OP-06, OP-07, AD510, ADS517, $E5534 in Gains >5 Available in Die Form ORDERING INFORMATION |! PACKAGE Ty = +25C OPERATING Vos MAX CERDIP PLASTIC Lcc TEMPERATURE quv) TO-99 8-PIN 8-PIN 20-CONTACT RANGE 25 OP37Au* OP37AZ* - - MIL 25 OP37EJ. OP37EZ OP37EP - INDICOM 60 OP37Bu" OP37BZ* - OP37BRC/883 MIL 60 OP37FJ OP37FZ OP37FP - IND/COM 100 OP37CJ* OP37CZ - - MIL 100 OP37GJ OP37GZ OP37GP - XIND 100 - - OP37GStt - XIND For devices processed in total compliance to MIL-STD-883, add /883 after part number. Consult factory for 883 data sheet. Burn-in is available on commercial and industrial temperature range parts in CerDIP, plastic DIP, and TO-can packages. For availability and burn-in information on SO package, contact your local sales office. tt GENERAL DESCRIPTION The OP-37 provides the same high performance as the OP-27, but the design is optimized for circuits with gains greater than five. This design change increases slew rate to 17V/usec and gain-bandwidth product to 63MHz. SIMPLIFIED SCHEMATIC The OP-37 provides the low offset and drift of the OP-07 plus higher speed and lower noise. Offsets down to 25zV and drift of 0.6nV/C maximum make the OP-37 ideal for precision instrumentation applications. Exceptionally low noise (e,=3.5nV// Hz at 10Hz), alow 1/f noise corner frequency of 2.7Hz, and the high gain of 1.8 million, allow accurate high-gain amplification of low-level signals. The lowinput bias current of t 10nA and offset current of 7nAare achieved by using a bias-current-cancellation circuit. Over the military temperature range this typically holds Ig and log to +20nA and 15nA respectively. The output stage has good load driving capability. A guaran- teed swing of + 10V into 6002 and low output distortion make the OP-37 an excellent choice for professional audio applications. PIN CONNECTIONS 8 Vos TRIM Vog TRIM 1 7 V4 IN2 6 OUT +IN3 SNC. 4V- (CASE) 8-PIN HERMETIC DIP - (Z-Suftix) (sSuttlx) EPOXY MINI-DIP (P-Suftix) 8-PIN SO (S-Suffix) OP-37BRC/883 LCC PACKAGE (RC-Suffix) L R3 Ra 02 ) @ Nag 06 t 8 T - c1 Vog Adi- 022 r-K axe rie R2* R23 R24 My > 021 Ro q 023 24 020) 019 bo OUTPUT NON- R12 INDUT aye a1 J a1 02B [02a an c3 Bh R5 R11 C4 INVERTING a3 PO I ROS INPUT (-) Ms o Ro | ait | ar2 KE 027 28 *R1& R2 ARE PERMANENTLY ADJUSTED 4 AT WAFER TEST FOR MINIMIM OFFSET VOLTAGE. ) q oV-OP-37 PSRR and CMRR exceed 120dB. These characteristics, coupled with long-term drift of 0.24V/month, allow the circuit designer to achieve performance levels previously attained only by discrete designs. Low-cost, high-volume production of the OP-37 is achieved by using on-chip zener-zap trimming. This reliable and stable offset trimming scheme has proved its effectiveness over many years of production history. The OP-37 brings low-noise instrumentation-type perfor- mance to such diverse applications as microphone, tape- head, and RIAA phono preamplifiers, high-speed signal con- ditioning for data acquisition systems, and wide-bandwidth instrumentation. ABSOLUTE MAXIMUM RATINGS (Note 4) Supply Voltage 0... cecesssseesessesserseeseeeeesessecsenseeseeeneens +22V Internal Voltage (Note 1) oo... eee eeseeeecereeteeeseeseneeterees +22V Output Short-Circuit Duration Indefinite Differential Input Voltage (Note 2) oo... eee cceseeeeeeteeee BO.7V Differential Input Current (Note 2) .... Storage Temperature Range 65C to 1 50C Operating Temperature Range OP-37A, OP-37B, OP-37C (J, Z, RC).........-55C to +125C OP-37E, OP-37F (J, Z) ...cccesessssesssssseeesseeees ~25C to +85C OP-37E, OP-37F (P) .......cccccessssesseescssssssetsneneenes 0C to +70C OP-37G (P, S, J, Z)... 40C to +85C Lead Temperature Range (Soldering, 60 sec) sadeaneaneeanes 300C Ju nction Temperature seseovesscaceseaceeseaesesseceeees 65C to +150C PACKAGE TYPE , , (NOTE 3) Be UNITS TO-99 (J) 150 18 C/W 8-Pin Hermetic DIP (Z) 148 16 C/W 8-Pin Plastic DIP (P) 103 43 C/W 20-Contact LCC (RC, TC) 98 38 Chw 8-Pin SO (S) 158 43 C NOTES: 1. For supply voltages less than +22V, the absolute maximum input voltage is equal to the supply voltage. The OP-37's inputs are protected by back-to-back diodes. Current limiting resistors are not used in order to achieve low noise. If differential input voltage exceeds +0.7V, the input current should be limited to 25mA. @,, is specified for worst case mounting conditions, i.e., Gin is specified for device in socket for TO, CerDIP, P-DIP, and LCC packages; @, , is specified for device soldered to printed circuit board for SO package. Absolute maximum ratings apply to both DICE and packaged parts, unless otherwise noted. 2. ELECTRICAL CHARACTERISTICS at Vs = +15V, Ta = 25C, unless otherwise noted. OP-37A/E OP-37B/F OP-37C/G PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Input Offset Voitage Vos (Note 1) _ 10 25 _ 20 60 _ 30 100 uv Long-Term V, g a os Vos/Time (Notes 2, 3) - 0.2 1.0 _ 0.3 1.6 _ 0.4 2.0 p//Mo Stability Input Offset Current los - 7 35 _ 9 50 - 12 75 nA Input Bias Current Ig _ +10 +40 _ +12 +55 _ +15 +80 nA 0.1Hz to 10Hz Input Noise Voltage enp- _ 0.08 0.18 _ 0.08 0.18 _ 0.09 0.25 Vp- P np-p (Notes 3, 5) HYP-P . fo = 10Hz (Note 3) _ 3.5 .5 _ 3.5 5.5 _ 3.8 8.0 Input Noise . en fo = 30Hz (Note 3) _ 34 4.5 _ 31 4.5 _ 3.3 .6 AVA Hz Voltage Density fg = 1000Hz (Note 3) ~ 3.0 3.8 _ 3.0 3.8 _ 3.2 45 Input Noise fo = 10Hz (Notes 3, 6) _ LZ 4.0 _ 17 4.0 _ 1.7 _ P . in fo = 30Hz (Notes 3, 6) _ 4.0 2.3 _ 1.0 2.3 _ 1.0 pAl/ Hz Current Density fo = 1000Hz (Notes 3, 6) _ 0.4 0.6 _ 0.4 0.6 _ 0.4 0.6 Input Resistance P . Rin (Note 7} 1.3 6 _ 0.94 5 _ 0.7 4 _ MQ Differential-Mode Input Resistance R - 3 _ _ 25 _ _ 2 _ Go Common-Mode INCM Input Voltage Range IVR 411.0 +12.3 _ $11.0 +123 _ +11.0 =12.3 _ Vv Common-Mode oa. . CMRR Vom = +11V 114 126 _ 106 123 _ 100 120 _ dB Rejection Ratio Power Supply ow. . PSSR Vg = +4V to 18V _ 1 10 _ 1 10 _ 2 20 wv Rejection Ratio R, = 2k0, Vo = 10V 1000 1800 _ 1000 1800 _ 700 1500 _ Large-Signal Ry, 2 1k, Vo = +10V 800 1500 800 1500 400 1500 _ , Voltage Gain Avo R, = 6000, Vg = +1V View g L ou 250 700 250 700 200 500 Vg = 44V, (Note 4) Output Voltage V, Ry, 2 2k0. +12.0 +13.8 _ #12.0 +13.8 _ 411.5 113.5 _ Vv Swing R, 2 6000 +10.0 11.65 _ #100 +115 _ 410.0 =11.5 _ Slew Rate SR R, = 2kQ (Note 4) 11 7 _ an 7 _ 11 17 _ V/ us . fo = 10kHz (Note 4) 45 63 _ 45 63 _ 45 63 _ Gain Bandwidth Prod. GBW MHz . fo = 1MHz _ 40 _ _ 40 _ _ 40 _OP-37 ELECTRICAL CHARACTERISTICS at Vs = + 15V, Ta = 25C, unless otherwise noted. (Continued) OP-37A/E OP-37B/F OP-37C/G PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Open-Loop Output R Vn=0.In=0 70 70 Resistance Onno 7 ~ ~ ~ 70 7 a Power Consumption Pg Vo =0 _ 90 140 _ 90 140 _ 100 170 mw Offset Adjustment Rp = 10k. _ +4.0 _ _ +40 _ _ +4.0 _ mV Range NOTES: 1. Input offset voltage measurements are performed by automated test equipment approximately 0.5 seconds after application of power. A/E grades guaranteed fully warmed up. Long-term input offset voltage stability refers to the average trend line of days are typically 2.54V refer to typical performance curve. Sample tested. Guaranteed by design. See test circuit and frequency response curve for 0.1Hz to 10Hz tester. See test circuit for current noise measurement. Guaranteed by input bias current. Vog vs. Time over extended periods after the first 30 days of operation. Excluding the initial hour of operation, changes in Vog during the first 30 NO & ELECTRICAL CHARACTERISTICS for Vs = +15V, -55C < Ta = + 125C, unless otherwise noted. OP-37A OP-37B OP-37C PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Input Offset Voltage Vos (Note 1) _ 30 60 _ 50 200 - 70 300 EV Average Input TCV Note 2 verage inp os (Note 2) _ 0.2 0.6 _ 0.3 13 _ 0.4 18 uVP?C Offset Drift TCVosn (Note 3) Input Offset Current log 15 50 - 22 85 _ 30 135 nA input Bias Current Ig _ +20 +60 +28 +95 _ +35 +150 nA Input Voltage Range IVR +10.3 411.5 _ +10.3 11.5 _ +10.2 #115 _ Vv Common-Mode . CMRR Vom = t10V 108 122 _ 100 119 _ 94 116 _ qB Rejection Ratio Power Supply oo | PSRR Vg = +4.5V to +18V - 2 16 _ 2 20 _ 4 51 uVv/V Rejection Ratio Li -Si | arge-Signal Avo Ry, = 2k, Vg =+10V 600 1200 500 1000 _ 300800 - V/mV Voltage Gain t Volt Output Voltage Vo Ry > 2k0 +116 +135 ~ 110 +18.2 +105 +13.0 ~ v Swing ELECTRICAL CHARACTERISTICS for V, =+1 5V,-25C <T, $ +85C for OP-37EJ/FJ and OP-37EZ/FZ, 0C<T, < +70C for OP-37EP/FP and 40C < T, < +85 for OP-37GP/GS/GJ/GZ, unless otherwise noted. OP-37E OP-37F OP-37G PARAMETER SYMBOL CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS Input Offset Voltage Vog _ 20 50 _ 40 140 _ 55 220 BV Average Input TCNos (Note 2) _ 0.2 0.6 - 0.3 1.3 - 0.4 18 wwe Offset Drift TCVosn (Note 3) Input Offset Current los _ 10 50 _ 14 85 - 20 135 nA input Bias Current lp +14 +60 - +18 +95 _ +25 +150 nA Input Voltage Range IVR +10.5 11.8 _ +105 +11.8 - +10.5 41.8 _ Vv Common-Mode CMRR Vom = 10V 110 124 _ 402 421 ~ 96 118 _ dB Rejection Ratio Power Supply PSRR Vg = 4.5V to +18V _ 2 15 - 2 16 _ 2 32 uVV Rejection Ratio Large-Signal Avo Ry > 2k, Vg =+10V 750 1500 700 1300 _ 450 1000 _ vim Voltage Gain Output Voltage Vo Ry > 2k +7 #13.6 _ +114 413.5 _ +110 +13.3 _ v Swing NOTES: 2. The TCVog performance is within the specifications unnulled or when 1. Input offset voltage measurements are performed by automated test nulled with Rp= 8k to 20k. TC Veg is 100% tested for A/E grades, sample equipment approximately 0.5 seconds after application of power. A/E tested for B/C/F/G grades. grades guaranteed fully warmed up. 3. Guaranteed by design.OP-37 DICE CHARACTERISTICS DIE SIZE 0.098 < 0.056 inch, 5488 sq. mils (2.49 < 1.42 mm, 3.54 sq. mm) NULL (-) INPUT (+) INPUT v- OUTPUT V+ NULL SN DEON o WAFER TEST LIMITS at Vs = + 15V, Ta = 25C for OP-37N, OP-37G and OP-37GR devices; Ta = 125 C for OP-37NT and OP-37GT devices, unless otherwise noted. OP-37NT OP-37N OP-37GT OP-37G OP-37GR PARAMETER SYMBOL CONDITIONS LIMIT LIMIT LIMIT LIMIT LIMIT UNITS Input Offset Voltage Vos (Note 1} 60 35 200 60 100 pV MAX Input Offset Current los 50 35 85 50 75 nA MAX Input Bias Current lg 60 +40 +95 +55 +80 nA MAX Input Voltage Range IVR 10.3 a1 +10.3 a1 +1 V MIN Gommon- Mode CMRR Vom =11V 108 114 100 106 100 = dBMIN Rejection Ratio Power Supply Ta = 25C, Vg = 4V to +18V 10 10 10 10 20 V/V MAX Rejection Ratio PSAR Ta = 125C, Vg = +4.5V to +18V 16 - 20 _ # - =+ 1 700 Large Signal Avo R_ = 2k, Vo =+10V 600 1000 500 000 V/mV MIN Voltage Gain R, 2 1kf, Vo = +10V _ 800 - 800 - . R,_ 2 2kn +115 12.0 +11.0 +12.0 115 Output Voltage Swing Yo R_ = 6000 +10.0 +10.0 +10.0 V MIN Power Consumption Pg Vo=0 - 140 - 140 170 mW MAX NOTES: For 25C characteristics of OP-37NT and OP-37GT devices, see OP-37N and OP-37G characteristics, respectively. 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. Consult factory to negotiate specifications based on dice lot qualification through sample lot asembly and testing. TYPICAL ELECTRICAL CHARACTERISTICS at Vs = + 15V, Ta = + 25C, unless otherwise noted. OP-37NT OP-37N OP-37GT OP-37G OP-37GR PARAMETER SYMBOL CONDITIONS TYPICAL TYPICAL TYPICAL TYPICAL TYPICAL UNITS Average Input Offset TCVog or Nulled or Unnulled 2 0.2 0.3 5 F Voltage Drift TCVogn Rp= 8kQ to 20kQ 08 04 wVhC Average Input Offset Current Drift TClog 80 80 130 130 180 parc Average Input Bias Current Drift TClp 100 100 160 160 200 pa/ec Input Noise fo = 10Hz 3.5 3.5 3.5 3.5 3.8 Voltage Densit en fo = 30Hz 3.1 3.1 3.1 3.1 3.3 W/V Hz 9 y fo = 1000Hz 3.0 3.0 3.0 3.0 32 Input Noise fo = 10Hz. 1.7 1.7 1.7 1.7 17 Crtent Donsit in fo = 30Hz 1.0 1.0 1.0 1.0 10 pah/Hz y fo = 1000Hz 0.4 04 0.4 0.4 0.4 Input Noise Voltage Cnp-p 0.1Hz to 10Hz 0,08 0.08 0.08 0.08 0.09 uVp.p Slew Rate SR R,_ 2 2kQ 17 7 W 7 7 Wns Gain Bandwidth Product GBW fo = 10kHz 63 63 68 63 63 MHz NOTE: 1. Input offset voltage measurements are performed by automated test equipment approximately 0.5 seconds after application of power.OP-37 TYPICAL PERFORMANCE CHARACTERISTICS NOISE-TESTER FREQUENCY RESPONSE (0.1Hz TO 10Hz) GAIN (dB) TEST TIME OF 10sec MUST BE USED TO LIMIT LOW FREQUENCY (<0.1Hz) GAIN, 0.01 0.1 1.0 10 100 FREQUENCY (Hz) INPUT WIDEBAND VOLTAGE NOISE vs BANDWIDTH (0.1Hz TO FREQUENCY INDICATED) 10 Ta = 25C Vg = +15V S 3 w a1 3 z= iat Qo gq F a > w 01 = x 0.01 100 1k 10k 100k BANDWIDTH (Hz) VOLTAGE NOISE DENSITY vs SUPPLY VOLTAGE | Ta = 25C e* AT 10Hz = eee ae wy AT 1kHz 23 = 3 2 al oO < BE a 2 > 1 0 10 20 30 40 TOTAL SUPPLY VOLTAGE (V+ V) (VOLTS) VOLTAGE NOISE DENSITY __v8 FREQUENCY Ta = 25C Vg = #15V Hz) ao veeo If CORNER = 27Hz VOLTAGE NOISE (nV/ 1 10 100 1000 FREQUENCY (Hz) TOTAL NOISE vs SOURCE RESISTANCE Ta = 25C a vs = 15V i> Hz) TOTAL NOISE (nVA RESISTOR NOISE ONLY 100 1k SOURCE RESISTANCE (9) 10k CURRENT NOISE DENSITY _ _v8 FREQUENCY _ CURRENT NOISE (pAA/Hz) I/f CORNER = 140Hz 10 100 Ik FREQUENCY (Hz) 10k A COMPARISON OF OP AMP VOLTAGE _ NOISE SPECTRA 741 Hz) 1/f CORNER LOW NOISE 10 AUDIO Vf CORNER OP AMP 27Hz 1V/t CORNER OP-37 VOLTAGE NOISE inv/ INSTRUMENTATION AUDIO RANGE RANGE, TO DC TO 20kHz a 10 100 1000 FREQUENCY (Hz) VOLTAGE NOISE DENSITY vs TEMPERATURE T T Vg = +15V Hz) AT 10Hz alt AT 1kHz La VOLTAGE NOISE (nV/A -50 ~25 0 25 50 75 100 125 - TEMPERATURE (C) SUPPLY CURRENT vs SUPPLY VOLTAGE 0, Ta = 25C BE - 2.0 Z| Ta = 55C SUPPLY CURRENT (mA) w 10 | 5 15 25 35 45 TOTAL SUPPLY VOLTAGE (VOLTS)OPEN-LOOP VOLTAGE GAIN (dB) OP-37 TYPICAL PERFORMANCE CHARACTERISTICS 60 40 20 20 OFFSET VOLTAGE (uv) 40 -60 75 -50 -25 O08 25 50 75 w 3 N a 20 a 3 ABSOLUTE CHANGE IN INPUT OFFSET VOLTAGE (u:V)} a | N OFFSET VOLTAGE DRIFT OF EIGHT REPRESENTATIVE UNITS vs TEMPERATURE OP-37C OP-37B OP-37A. OP-37B OP-37. OP-37A TRIMMING WITH 10k POT DOES NOT CHANGE TCVos OP-37C 100 125 150 175 TEMPERATURE (C) OFFSET VOLTAGE CHANGE DUE TO THERMAL SHOCK Vg = 18V Ta= | Ta= 70C 26C DEVICE IMMERSED iN 70C OIL BATH 20 40 60 80 TIME (SEC) 100 OPEN-LOOP GAIN vs FREQUENCY Ta = +25C Vg = =15V Ry > 2k2 103 104 105 FREQUENCY (Hzi 10 102 PHASE MARGIN (DEG) SLEW RATE (V/us) LONG-TERM OFFSET VOLTAGE DRIFT OF SIX REPRESENTATIVE UNITS on FO CHANGE IN OFFSET VOLTAGE (:V} 0 1 2 3 4 5 6 TIME (MONTHS} INPUT BIAS CURRENT vs TEMPERATURE 50 a on On a ] 40 Vg = +15V +4 g 5 al N 30 \ OP-37 2 | KN 2 ool | NN 2 WN 'N MN OP-37B 2 NARS : 2 10 pL i] |! oP-37A 0 LU 50 25 0 2% 50 75 TEMPERATURE (@C) 700 125 SLEW RATE, GAIN BANDWIDTH PRODUCT, PHASE MARGIN vs TEMPERATURE 80 90 75 Vg = +15V 85 70 80 150 10kHz) 65 60 55 30 25 20 16 10 -50 -25 0 425 TEMPERATURE (C} +50 +75 75 70 65 60 55 50 45 GAIN-BANDWIDTH PRODUCT (MHz) (f 40 +100 +125 GAIN (dB) -10 100k 1M WARM-UP OFFSET VOLTAGE DRIFT Ta = +25C Vg = +15V OP-37C/G OP-37B/F OP-37A/E CHANGE IN INPUT OFFSET VOLTAGE (pV) 1 2 3 4 5 TIME AFTER POWER ON (MINUTES) INPUT OFFSET CURRENT vs TEMPERATURE 50 a 5 Vg = #15V we a INPUT OFFSET CURRENT {nA} N 5 | OP-37A 0 ~75 50 25 0 25 50 75 TEMPERATURE (C) 100 125 GAIN, PHASE SHIFT vs FREQUENCY 60 -80 : eee Ue 40 -120 30 -140 20 -160 PHASE SHIFT (DEG) -180 ~200 -220 100M 10M FREQUENCY (Hz)OP-37 TYPICAL PERFORMANCE CHARACTERISTICS OPEN-LOOP VOLTAGE GAIN vs SUPPLY VOLTAGE PERCENT OVERSHOOT 2.5 T RL = 2k2 volta - ose AS > Ta= 2sre LY RL = 1k2 & 1) ae 2 Z15 z YY oO i Lo 91.0 7 4 2 a 1 6 0.5 4 0.0 0 10 20 30. 40 50 TOTAL SUPPLY VOLTAGE (VOLTS) SMALL-SIGNAL OVERSHOOT vs CAPACITIVE LOAD 80 7 - Vg = 15V VIN = 20mV Ay= +6 (160, 2500) | 60 7 | 4 20 / 0 Q 500 1000 1800 CAPACITIVE LOAD (pF) 2000 SHORT-CIRCUIT CURRENT vs TIME 60 50 Ty = 425 N Vg = t15V 40 S= Isc(+) 30 SHORT-CIRCUIT CURRENT (mA) " | 10 | 0 1 2 3 4 5 TIME FROM OUTPUT SHORTED TO GROUND (MINUTES) -10V CMRR (dB} PEAK-TO-PEAK AMPLITUDE (VOLTS) 140 120 100 80 60 40 MAXIMUM OUTPUT SWING vs FREQUENCY Vg = 15V = 25 Tp = 25C 104 10 108 FREQUENCY (Hz} 107 LARGE-SIGNAL TRANSIENT Vg = +15V Ay = 45 (1k2, 2502) Ty = +25C CMRR vs FREQUENCY TTT | Vg = 18V Ta = +25C TT Yon = 10v TT \ | 10k 100k FREQUENCY (Hz) 10M MAXIMUM OUTPUT (VOLTS) +50mV ov -50mV COMMON-MODE RANGE (VOLTS} MAXIMUM OUTPUT VOLTAGE vs LOAD RESISTANCE POSITIVE SWING NEGATIVE SWING Ta = 25C Vg = 15V 100 1k 10k LOAD RESISTANCE (22) SMALL-SIGNAL TRANSIENT RESPONSE _ Vg = 15V Ay +5 (1kQ, 2502} Ty = 425C COMMON-MODE INPUT RANGE vs SUPPLY VOLTAGE Ta = 58C Ta = 125C Ta = 25C Ta = -55C Ta = 26C Ta = 125C QO +5 +10 +15 SUPPLY VOLTAGE (VOLTS) +20OP-37 TYPICAL PERFORMANCE CHARACTERISTICS NOISE TEST CIRCUIT (0.1Hz TO 10Hz ) VOLTAGE GAIN = 60,000 VOLTAGE NOISE (nV) NOTE: NOTE: ALL CAPACITOR VALUES ARE FOR NON-POLARIZED CAPACITORS ONLY. PSRR vs FREQUENCY TA = 25C a & o Ty = +25C Vg = 15V Ay = +5 Vg = 20Vp-p = u = S a NEGATIVE SUPPLY 2 5 POSITIVE SUPPLY 2 3 SLEW RATE (V/us) POWER SUPPLY REJECTION RATIO (dB) & o y o 1 1 10 100) 1k 610k 100k IM 10M 100M 100 FREQUENCY (Hz} Tk APPLICATIONS INFORMATION OP-37 Series units may be inserted directly into 725, OP-06, OP-07, and OP-05 sockets with or without removal of external compensation or nulling components. Additionally, the OP- 37 may be fitted to unnulled 741-type sockets; however, if conventional 741 nulling circuitry is in use, it should be modi- fied or removed to ensure correct OP-37 operation. OP-37 offset voltage may be nulled to zero (or other desired setting) using a potentiometer (see offset nulling circuit). The OP-37 provides stable operation with load capacitances of up to 1000pF and + 10V swings; larger capacitances should be decoupled with a 502 resistor inside the feedback loop. Closed-loop gain must be at least five. For closed-loop gain between five to ten, the designer should consider both the OP-27 and the OP-37. For gains above ten, the OP-37 has a clear advantage over the unity-gain-stable OP-27. Thermoelectric voltages generated by dissimilar metals at the input terminal contacts can degrade the drift perfor- mance. Best operation will be obtained when both input contacts are maintained at the same temperature. LOW-FREQUENCY NOISE 0.1Hz TO 10Hz PEAK-TO-PEAK NOISE Observation time limited to 10 seconds. SLEW RATE vs LOAD LOAD RESISTANCE (9) OPEN-LOOP VOLTAGE GAIN vs LOAD RESISTANCE Ty = 25C Vg = #15V OPEN-LOOP VOLTAGE GAIN (V/uV) 400 1k 10k LOAD RESISTANCE (2} 100k SLEW RATE vs SUPPLY VOLTAGE 20 ose _ Ta = +25C RISE Le eer Ayet = +8 =a 15 a Po rALL = r LZ a T7 = a al a 5 0 10k 100k +3 +6 +9 12 +15 +18 21 SUPPLY VOLTAGE (VOLTS) OFFSET NULLING CIRCUIT OFFSET VOLTAGE ADJUSTMENT The input offset voltage of the OP-37 is trimmed at wafer level. However, if further adjustment of Vos is necessary, a 10k trim potentiometer may be used. TCVosis not degraded (see offset nulling circuit). Other potentiometer values from 1kQ to 1MQ can be used with a slight degradation (0.1 to 0.24V/ C) of TCVog. Trimming to a value other than zero creates a drift of approximately (Vg/300) wV/ C. For exam-OP-37 ple, the change in TCVog will be 0.33uV/ C if Vosis adjusted to 100uV. The offset-voltage adjustment range with a 10k0. potentiometer is +4mvV. If smaller adjustment range is re- quired, the nulling sensitivity can be reduced by using a smaller pot in conjunction with fixed resistors. For example, the network below will have a +280uV adjustment range. 1k&2 POT 1 4.7kQ 4.7kQ 8 V+ BURN-IN CIRCUIT NOISE MEASUREMENTS To measure the 80nV peak-to-peak noise specification of the OP-37 in the 0.1Hz to 10Hz range, the following precautions must be observed: (1) The device has to be warmed-up for at least five minutes. As shown in the warm-up drift curve, the offset voltage typically changes 4zV due to increasing chip tempera- ture after power-up. In the 10 second measurement inter- val, these temperature-induced effects can exceed tens- of- nanovolts. , (2) For similar reasons, the device has to be well-shielded from air currents. Shielding minimizes thermocoupie effects. (3) Sudden motion in the vicinity of the device can also feed- through to increase the observed noise. (4) The test time to measure 0.1Hz-to-10Hz noise should not exceed 10 seconds. As shown in the noise-tester fre- quency response curve, the 0.1Hz corner is defined by only one zero. The test time of 10 seconds acts as an additional zero to eliminate noise contributions from the frequency band below 0.1Hz. (5) A noise-voltage-density test is recommended when measuring noise on a large number of units. A 10Hz noise-voltage-density measurement will correlate well with a 0.1Hz-to-10Hz peak-to-peak noise reading, since both results are determined by the white noise and the location of the 1/f corner frequency. OPTIMIZING LINEARITY Best linearity will be obtained by designing for the minimum output current required for the application. High gain and excellent linearity can be achieved by operating the op amp with a peak output current of less than + 10mA. INSTRUMENTATION AMPLIFIER A three-op-amp instrumentation amplifier provides high gain and wide bandwidth. The input noise of the circuit below is 4.9nV/V/ Hz . The gain of the input stage is set at 25 and the gain of the second stage is 40; overall gain is 1000. The amplifier bandwidth of 800kHz is extraordinarily good fora precision instrumentation amplifier. Set to a gain of 1000, this yields a gain-bandwidth product of 800MHz. The full-power bandwidth fora 20Vp-p output is 250kHz. Potentiometer R7 provides quadrature trimming to optimize the instrumenta- tion amplifiers AC common-mode rejection. INPUT R5 R8 50082 0.1% 20k22 0.1% VY ' WY Vout 50022 0.1% * TRIM R2 FOR Ayo, = 1000 R10 TRIM R10 FOR de CMRR 50082 * TRIM R7 FOR MINIMUM VoyT AT Vem = 20V p-p, 10KHz = 140 120 Rg = 1k2, BALANCED = 2 a CMRR (dB) Rg = 1002, 1k UNBALANCED PUT | Till 2 3 Tp = +25C 60 F vg = +15V Vom = 20V p-p AC TRIM @ 10KHz, Rg = 0 40 10 100 1k 10k 100k iM FREQUENCY (Hz) COMMENTS ON NOISE The OP-37 is a very low-noise monolithic op amp. The out- standing input voitage noise characteristics of the OP-37 are achieved mainly by operating the input stage ata high quies- cent current. The input bias and offset currents, which would normally increase, are held to reasonable values by the input- bias-current cancellation circuit. The OP-37A/E has Ig and los of only +40nA and 35nA respectively at 25C. This is particularly important when the input has a high source- resistance. In addition, many audio amplifier designersOP-37 prefer to use direct coupling. The high Ip, TCVos of previous designs have made direct coupling difficult, if notimpossible, to use. Voltage noise is inversely proportional to the square-root of bias current, but current noise is proportional to the square- root of bias current. The OP-37's noise advantage disappears when high source-resistors are used. Figures 1, 2, and 3 compare OP-37 observed total noise with the noise perfor- mance of other devices in different circuit applications. Total noise = [(Voltage noise)? + (current noise X Rg)* + (resistor noise2 ]1/2 Figure 1 shows noise-versus-source-resistance at 1000Hz. The same plot applies to wideband noise. To use this plot, just multiply the vertical scale by the square-root of the bandwidth. Rgs< 1kQ, total noise increases, but is dominated by the resis- tor noise rather than current or voltage noise. It is only -10- NOISE vs SOURCE RESISTANCE 10Hz NOISE vs (INCLUDING RESISTOR NOISE) SOURCE RESISTANCE AT 1000Hz (INCLUDES RESISTOR NOISE) 100 100 a 50 5a z & -08/108 2 2 2 10 s 10 zs RNS B seu 2 AOE ro cee Rs1 Y ONLY 0 100 500 1k 5k 10k 50k 50 100 500 1k 5k 10k 50k Figure 1 Rg ~ SOURCE RESISTANCE (52) Figure 3 Rg - SOURCE RESISTANCE (1) beyond Rgof 20kN that current noise starts to dominate. The PEAK-TO-PEAK NOISE (0.1 to argument can be made that current noise is not important for 10Hz) vs SOURCE RESISTANCE applications with low-to-moderate source resistances. The (INCLUDES RESISTOR NOISE) crossover between the OP-37 and OP-07 and OP-08 noise Ve oceurs in the 15-to-40k0 region. 500 Figure 2 shows the 0.1Hz-to-10Hz peak-to-peak noise. Here the picture is less favorable; resistor noise is negligible, cur- 2 rent noise becomes important because itis inversely propor- 8 tional to the square-root of frequency. The crossover with the 2 100 OP-07 occurs in the 3-to 5kN range depending on whether rs balanced or unbalanced source resistors are used (at3kN the 2 0 1 Rg UNMATCHED 1p, log error also can be three times the Vos spec.). Mw e.g.Rg=Rg1=10k,Ag2=0 Fi r2ngMaroHE Therefore, for iow-frequency applications, the OP-07 is bet- ter than the OP-27/37 when Rgs> 3kN. The only exception is NOISE ONLY when gain error is important. Figure 3 illustrates the 10Hz 10 noise. As expected, the results are between the previous two 50 100 500 1k 5k 10k 50k . Rg - SOURCE RESISTANCE (2) figures. Figure 2 . . . For reference, typical source resistances. of some signal sources are listed in Table 1. Table 1 SOURCE DEVICE IMPEDANCE COMMENTS Strain gauge <000 Typically used in low-frequency applications. Magnetic <15000 Low Ig very important to reduce tapehead self-magnetization problems when direct coupling is used. OP-37 Ip can be neglected. Magnetic <15000, Similar need for low lg in direct phonograph coupled applications. OP-37 will not cartridges introduce any self-magnetization problem. Linear variable <15000, Used in rugged servo-feedback differential applications. Bandwidth of interest transformer is 400Hz to 5kHz.OP-37 AUDIO APPLICATIONS The following applications information has been abstracted from a PMI article in the 12/20/80 issue of Electronic Design magazine and updated. C4 (2) 220uF y| 4) Ro 100k2 MOVING MAGNET LF ROLLOFF = CARTRIGE INPUT = OUT IN Ra c3 47.5 ae fa bo KO | 1500F 0.47 uF l 2 ouTPUT 35 oo BkKQ 0.03uF 5 15k Q *_o c2 R2 7a7eerT OOF R3 1002 i G = 1kHz GAIN - y = 0,101 (i + R1) RB! = 98.677 (39.9 dB) AS SHOWN Figure 4 ) Figure 4 is an example of a phono pre-amplifier circuit using the OP-27 for Ay; Ry-Ro-C1-C2 form a very accurate RIAA network with standard component values. The popular method to accomplish RIAA phono equalization is to employ frequency-dependent feedback around a high-quality gain block. Properly chosen, an RC network can provide the three necessary time constants of 3180, 318, and 75us.! For initial equalization accuracy and stability, precision metal-film resistors and film capacitors of polystyrene or polypropylene are recommended since they have low voltage coefficients, dissipation factors, and dielectric absorption.4 (High-K ceramic capacitors should be avoided here, though low-K ceramics such as NPO types, which have excellent dissipation factors, and somewhat lower dielectric absorption can be considered for small values or where space is at a premium.) The OP-27 brings a 3.2nV/\/Hz_ voltage noise and 0.45 pA/V Hz current noise to this circuit. To minimize noise from other sources, Rg is set to a value of 1009, which generates a voltage noise of 1.8nWV Hz . The noise in- creases the 3.2nW./ Hz of the amplifier by only 0.7dB. With a 1kQ source, the circuit noise measures 63dB below a 1mV reference level, unweighted, in a 20kHz noise bandwidth. Gain (G) of the circuit at 1kHz can be calculated by the expression: G=0.101 (1+ 1) Rg For the values shown, the gain is just under 100 (or 40dB). Lower gains can be accommodated by increasing R3, but gains higher than 40dB will show more equalization errors because of the 8MHz gain-bandwidth of the OP-27. -11- This circuit is capable of very low distortion over its entire range, generally below 0.01% at levels up to 7V rms. At 3V output levels, it will produce less than 0.03% total harmonic distortion at frequencies up to 20kHz. Capacitor C3 and resistor R4 form a simple -6dB-per-octave rumble filter, with a corner at 22Hz. As an option, the switch- selected shunt capacitor C4, a nonpolarized electrolytic, bypasses the low-frequency rolloff. Placing the rumble fii- ters high-pass action after the preamp has the desirable result of discriminating against the RIAA-amplified low- frequency noise components and pickup-produced low- frequency disturbances. A preamplifier for NAB tape playback is similar to an RIAA phono preamp, though more gain is typically demanded, along with equalization requiring a heavy low-frequency boost. The circuit in Fig. 4 can be readily modified for tape use, as shown by Fig. 5. O47 uF TAPE HEAD Ra 16kO. T1 = 3180us T2 =50us Figure 5 While the tape-equalization requirement has a flat high- frequency gain above 3kHz (To = 50us), the amplifier need not be stabilized for unity gain. The decompensated OP-37 provides a greater bandwidth and slew rate. For many appli- cations, the idealized. time constants shown may require trimming of R; and Rp to optimize frequency response for nonideal tape-head performance and other factors. The network values of the configuration yield a 50dB gain at 1kHz, and the dc gain is greater than 70dB. Thus, the worst- case output offset is just over 500mvV. A single 0.47 F output capacitor can block this level without affecting the dynamic range. The tape head can be coupled directly to the amplifier input, since the worst-case bias current of 85nA with a 400mH, 100 pin. head (such as the PRB2H7K) will not be troublesome. One potential tape-head problem is presented by amplifier bias-current transients which can magnetize a head. The OP-27 and OP-37 are free of bias-current transients upon power up or power down. However, itis always advantageous to control the speed of power supply rise and fall, to elimi- nate transients. In addition, the de resistance of the head should be carefully controlled, and preferably below 1k. For this configura- tion, the bias-current-induced offset voltage can be greater than the 170uV maximum offset if the head resistance is not sufficiently controlled.OP-37 A simple, but effective, fixed-gain transformerless micro- phone preamp (Fig. 6) amplifies differential signals from low- impedance microphones by 50dB, and has an input impe- dance of 2k. Because of the high working gain of the circuit, an OP-37 helps to preserve bandwidth, which will be 110kHz. As the OP-37 is a decompensated device (minimum stable gain of 5), a dummy resistor, Rp, may be necessary, if the microphone is to be unplugged. Otherwise the 100% feed- back from the open input may cause the amplifier to oscillate. R1 R6 1kQ. 41 R2 LOW IMPEDANCE MICROPHONE INPUT {Z = 50 TO 2002) Ri p 30k2 RQ OUT R3_Ra RIT R2 Tk Figure 6 Common-mode input-noise rejection will depend upon the match of the bridge-resistor ratios. Either close-tolerance (0.1%) types should be used, or R4 should be trimmed for best CMRR. All resistors should be metal-film types for best sta- bility and low noise. Noise performance of this circuit is limited more by the input resistors R, and Ro than by the op amp, as. R; and Ro each generate a 4nWV/ Hz noise, while the op amp generates a 3.2nWV/ Hz noise. The rms sum of these predominant noise sources will be about 6nW./ Hz , equivalent to 0.9uV in a 20kHz noise bandwidth, or nearly 61dB below a 1mV input signal. Measurements confirm this predicted performance. For applications demanding appreciably lower noise, a high- quality microphone-transformer-coupled preamp (Fig. 7) incorporates the internally compensated OP-27. T; is a JE-115K-E 1500/15k0. transformer which provides an opti- mum source resistance for the OP-27 device. The circuit has an overall gain of 40dB, the product of the transformers voltage setup and the op amps voltage gain. Gain may be trimmed to other levels, if desired, by adjusting Ro or Rj. Because of the low offset voltage of the OP-27, the output offset of this circuit will be very low, 1.7mV or less, fora -12- OUTPUT bo SOURCE *T1 JENSEN JE-115K-E JENSEN TRANSFORMERS 10735 Burbank Blvd. N. Hollywood, CA 91601 Figure 7 40dB gain. The typical output blocking capacitor can be eliminated in such cases, but is desirable for higher gains to eliminate switching transients. Capacitor C2 and resistor Ro form a 2us. time constant in this circuit, as recommended for optimum transient response by the transformer manufacturer. With C2 in use, A; must have unity-gain stability. For situations where the 2us time con- stant is not necessary, C2 can be deleted, allowing the faster OP-37 to be employed. Some comment on noise is appropriate to understand the capability of this circuit. A 1500 resistor and R; and Regain resistors connected to a noiseless amplifier will generate 220 nv of noise in a 20kHz bandwidth, or 73dB below a 1mV reference level. Any practical amplifier can only approach this noise level; it can never exceed it. With the OP-27 and T, specified, the additional noise degradation will be close to 3.6dB.(or -69.5 referenced to 1mV). References 1. Lipshitz, S.P, On RIAA Equalization Networks, JAES, Vol. 27, June 1979, p. 458-481. Jung, W.G., /C Op Amp Cookbook, 2nd Ed., H.W. Sams and Company, 1980. Jung, W.G., Audio IC Op Amp Applications, 2nd Ed., H.W. Sams and Company, 1978. Jung, W.G., and Marsh, R.M., Picking Capacitors, Audio, February & March, 1980. Otala, M., Feedback-Generated Phase Nonlinearity in Audio Amplifiers, London AES Convention, March 1980, preprint 1976. Stout, D.F., and Kaufman, M., Handbook of Operational Amplifier Circuit Design, New York, McGraw Hill, 1976. 2. 3.