a Low Noise, Precision, High Speed Operational Amplifier (A VCL > 5) OP37 The output stage has good load driving capability. A guaranteed swing of 10 V into 600 W and low output distortion make the OP37 an excellent choice for professional audio applications. FEATURES Low Noise, 80 nV p-p (0.1 Hz to 10 Hz) 3 nV//Hz @ 1 kHz Low Drift, 0.2 V/C High Speed, 17 V/s Slew Rate 63 MHz Gain Bandwidth Low Input Offset Voltage, 10 V Excellent CMRR, 126 dB (Common-Voltage @ 11 V) High Open-Loop Gain, 1.8 Million Replaces 725, OP-07, SE5534 In Gains > 5 Available in Die Form PSRR and CMRR exceed 120 dB. These characteristics, coupled with long-term drift of 0.2 mV/month, allow the circuit designer to achieve performance levels previously attained only by discrete designs. Low-cost, high-volume production of the OP37 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. GENERAL DESCRIPTION The OP37 brings low-noise instrumentation-type performance to such diverse applications as microphone, tapehead, and RIAA phono preamplifiers, high-speed signal conditioning for data acquisition systems, and wide-bandwidth instrumentation. The OP37 provides the same high performance as the OP27, but the design is optimized for circuits with gains greater than five. This design change increases slew rate to 17 V/ms and gain-bandwidth product to 63 MHz. PIN CONNECTIONS The OP37 provides the low offset and drift of the OP07 plus higher speed and lower noise. Offsets down to 25 mV and a maximum drift of 0.6 mV/C make the OP37 ideal for precision instrumentation applications. Exceptionally low noise (en= 3.5 nV/ @ 10 Hz), a low 1/f noise corner frequency of 2.7 Hz, and the high gain of 1.8 million, allow accurate high-gain amplification of low-level signals. 8-Lead Hermetic DIP (Z Suffix) Epoxy Mini-DIP (P Suffix) 8-Lead SO (S Suffix) The low input bias current of 10 nA and offset current of 7 nA are achieved by using a bias-current cancellation circuit. Over the military temperature range this typically holds IB and IOS to 20 nA and 15 nA respectively. VOS TRIM 1 8 VOS TRIM -IN 2 7 V+ +IN 3 6 OUT V- 4 5 NC OP37 NC = NO CONNECT SIMPLIFIED SCHEMATIC V+ R3 Q6 R1* 1 8 VOS ADJ. C2 R4 Q22 R2* R23 Q21 Q24 Q23 Q46 C1 R24 R9 Q20 Q1A Q1B Q2B Q19 OUTPUT R12 Q2A NON-INVERTING INPUT (+) C3 R5 C4 Q3 INVERTING INPUT (-) Q11 Q26 Q12 Q27 Q45 Q28 *R1 AND R2 ARE PERMANENTLY ADJUSTED AT WAFER TEST FOR MINIMUM OFFSET VOLTAGE. V- REV. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 (c) Analog Devices, Inc., 2002 OP37 ABSOLUTE MAXIMUM RATINGS 4 ORDERING GUIDE Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 V Internal Voltage (Note 1 ) . . . . . . . . . . . . . . . . . . . . . . . . . 22 V Output Short-Circuit Duration . . . . . . . . . . . . . . . . . Indefinite Differential Input Voltage (Note2) . . . . . . . . . . . . . . . . . 0.7 V Differential Input Current (Note 2) . . . . . . . . . . . . . . . . 25 mA Storage Temperature Range . . . . . . . . . . . . . -65C to +150C Operating Temperature Range OP37A . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55C to +125C OP37E (Z) . . . . . . . . . . . . . . . . . . . . . . . . . . -25C to +85C OP37E, OP-37F (P) . . . . . . . . . . . . . . . . . . . . . 0C to 70C OP37G (P, S, Z) . . . . . . . . . . . . . . . . . . . . . -40C to +85C Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300C Junction Temperature . . . . . . . . . . . . . . . . . . -45C to +150C JA3 JC Unit 8-Lead Hermetic DIP (Z) 148 8-Lead Plastic DIP (P) 103 8-Lead SO (S) 158 16 43 43 C/W C/W C/W Package Type TA = 25C VOS MAX (V) 25 25 60 100 100 CerDIP 8-Lead OP37AZ* OP37EZ OP37GZ Plastic 8-Lead Operating Temperature Range OP37EP OP37FP* OP37GP OP37GS MIL IND/COM IND/COM XIND XIND *Not for new design, obsolete, April 2002. NOTES 1 For supply voltages less than 22 V, the absolute maximum input voltage is equal to the supply voltage. 2 The OP37'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 0.7 V, the input Current should be limited to 25 mA. 3 JA is specified for worst case mounting conditions, i.e., JA is specified for device in socket for TO, CerDIP, P-DIP, and LCC packages; JA is specified for device soldered to printed circuit board for SO package. 4 Absolute maximum ratings apply to both DICE and packaged parts, unless otherwise noted. CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the OP37 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. -2- WARNING! ESD SENSITIVE DEVICE REV. B OP37 SPECIFICATIONS ( V = 15 V, T = 25C, unless otherwise noted.) S Parameter Input Offset Voltage Long-Term Stability Input Offset Current Input Bias Current Input Noise Voltage Input Noise Voltage Density Large Signal Voltage Gain Output Voltage Swing Min OP37A/E Typ Max Min OP37F Typ Max Min OP37G Typ Max Symbol Conditions VOS Note 1 10 25 20 60 30 100 mV VOS/Time Notes 2, 3 0.2 1.0 0.3 1.5 0.4 2.0 mV/Mo IOS 7 35 9 50 12 75 nA IB 10 40 12 55 15 80 nA Unit enp-p 1 Hz to 10 Hz3, 5 0.08 0.18 0.08 0.18 0.09 0.25 mV p-p en fO = 10 Hz3 fO = 30 Hz3 fO = 1000 Hz3 3.5 3.1 3.0 5.5 4.5 3.8 3.5 3.1 3.0 5.5 4.5 3.8 3.8 3.3 3.2 8.0 5.6 4.5 nV// Hz fO = 10 Hz3, 6 fO = 30 Hz3, 6 fO = 1000 Hz3, 6 1.7 1.0 0.4 4.0 2.3 0.6 1.7 1.0 0.4 4.0 2.3 0.6 1.7 1.0 0.4 0.6 Input Noise Current Density iN Input Resistance Differential Mode Input Resistance Common Mode Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio A RIN Note 7 1.3 RINCM 6 0.9 3 IVR 45 0.7 2.5 pA// Hz 4 MW 2 GW 11 12.3 11 12.3 11 12.3 V 114 126 106 123 100 120 dB CMRR VCM = 11 V PSSR VS = 4 V to 18 V AVO RL 2 kW, VO = 10 V RL 1 kW, Vo = 10 V RL 600 W, VO = 1 V, V S 44 RL 2 kW RL 600 W RL 2k W4 12.0 13.8 10 11.5 11 17 12.0 13.8 10 11.5 11 17 11.5 13.5 10 11.5 11 17 V V V/ms fO = 10 kHz4 fO = 1 MHz 45 45 45 63 40 MHz MHz 70 W VO Slew Rate SR Gain Bandwidth Product GBW Open-Loop Output Resistance RO Power Consumption Pd Offset Adjustment Range 1 10 1 10 2 20 mV/ V 1000 1800 1000 1800 700 1500 V/mV 800 1500 800 1500 400 1500 V/mV 250 700 250 700 200 500 V/mV 63 40 VO = 0, IO = 0 70 VO = 0 90 RP = 10 kW 4 63 40 70 140 90 4 140 100 4 170 mW mV 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. 2 Long term input offset voltage stability refers to the average trend line of V OS vs. Time over extended periods after the first 30 days of operation. Excluding the initial hour of operation, changes in V OS during the first 30 days are typically 2.5 mV--refer to typical performance curve. 3 Sample tested. 4 Guaranteed by design. 5 See test circuit and frequency response curve for 0.1 Hz to 10 Hz tester. 6 See test circuit for current noise measurement. 7 Guaranteed by input bias current. REV. B -3- OP37-SPECIFICATIONS Electrical Characteristics ( V = 15 V, -55C < T < +125C, unless otherwise noted.) S Parameter Input Offset Voltage Average Input Offset Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio A OP37C Typ Max Unit 25 30 100 mV 0.2 0.6 0.4 1.8 mV/C IOS 15 50 30 135 nA IB 20 60 35 150 nA Min Conditions VOS Note 1 10 TCVOS TCVOSN Note 2 Note 3 IVR Large-Signal Voltage Gain CMRR VCM = 10 V PSRR VS = 4.5 V to 18 V AVO Output Voltage Swing OP37A Typ Symbol VO Max Min 10.3 11.5 10.2 11.5 V 108 122 94 116 dB 2 16 4 51 mV/ V RL 2 kW, VO = 10 V 600 1200 300 800 V/mV RL 2 kW 11.5 13.5 10.5 13.0 V (VS = 15 V, -25C < TA < +85C for OP37EZ/FZ, 0C < TA < 70C for OP37EP/FP, and -40C < TA Electrical Characteristics < +85C for OP37GP/GS/GZ, unless otherwise noted.) Parameter Input Offset Voltage Average Input Offset Drift Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Voltage Swing Symbol Conditions Min OP37E Typ Max Min OP37F Typ Max Min OP37C Typ Max Unit 20 50 40 140 55 220 mV 0.2 0.6 0.3 1.3 0.4 1.8 mV/C IOS 10 50 14 85 20 135 nA IB 14 60 18 95 25 150 nA VOS TCVOS TCVOSN Note 2 Note 3 IVR CMRR VCM = 10 V PSRR VS = 4.5 V to 18 V AVO VO 10.5 11.8 10.5 11.8 10.5 11.8 V 108 100 94 dB 122 2 RL 2 kW, VO = 10 V 750 RL 2 kW 11.7 13.6 15 1500 119 2 700 1300 11.4 13.5 16 116 4 32 mV/ V 450 1000 V/mV 11 13.3 V 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. 2 The TC VOS performance is within the specifications unnulled or when nulled withRP = 8 kW to 20 kW. TC VOS is 100% tested for A/E grades, sample tested for F/G grades. 3 Guaranteed by design. -4- REV. B OP37 BINDING DIAGRAM 1 1990 1427U 8 1. 2. 3. 4. 6. 7. 8. NULL (-) INPUT (+) INPUT V- OUTPUT V+ NULL 2 3 7 6 4 Wafer Test Limits Parameter Input Offset Voltage Input Offset Current Input Bias Current Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain (VS = 15 V, TA = 25C for OP37N, OP37G, and OP37GR devices; TA = 125C for OP37NT and OP37GT devices, unless otherwise noted.) Symbol Conditions OP37NT Limit OP37N Limit OP37GT Limit OP37G Limit OP37GR Limit Unit VOS Note 1 60 35 200 60 100 mV MAX IOS 50 35 85 50 75 nA MAX IB 60 40 95 55 80 nA MAX IVR 10.3 11 10.3 11 11 V MIN 108 114 100 106 100 dB MIN 10 10 10 20 mV/V MAX CMRR VCM = 11 V PSRR TA = 25C, VS = 4 V to 18 V 10 TA = 125C, VS = 4.5 V to 18 V 16 AVO RL 2 kW, VO = 10 V RL 1 kW, VO = 10 V Output Voltage Swing VO Power Consumption RL 2 kW RL 600 kW Pd VO = 0 600 1000 500 800 11.5 mV/V MAX 20 12 10 1000 700 800 11 140 V/mV MIN V/mV MIN 12 10 11.5 10 V MIN V MIN 140 170 mW MAX NOTES For 25C characterlstics of OP37NT and OP37GT devices, see OP37N and OP37G 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 assembly and testing. REV. B -5- OP37 Typical Electrical Characteristics (V = 15 V, T = 25C, unless otherwise noted.) S Parameter Average Input Offset Voltage Drift Average Input Offset Current Drift Average Input Bias Current Drift Input Noise Voltage Density OP37NT Typical OP37N Typical OP37GT Typical OP37G Typical OP37GR Typical Unit TCVOS or Nulled or Unnulled TCVOSN RP = 8 kW to 20 kW 0.2 0.2 0.3 0.3 0.4 mV/C TCIOS 80 80 130 130 180 pA/C TCIB 100 100 160 160 200 pA/C fO = 10 Hz fO = 30 Hz fO = 1000 Hz 3.5 3.1 3.0 3.5 3.1 3.0 3.5 3.1 3.0 3.5 3.1 3.0 3.8 3.3 3.2 nV//Hz nV//Hz nV//Hz fO = 10 Hz fO = 30 Hz fO = 1000 Hz 1.7 1.0 0.4 1.7 1.0 0.4 1.7 1.0 0.4 1.7 1.0 0.4 1.7 1.0 0.4 pA// Hz pA// Hz pA// Hz 0.1 Hz to 10 Hz RL 2k W 0.08 17 0.08 17 0.08 17 0.08 17 0.09 17 mV p-p V/ms fO = 10 kHz 63 63 63 63 63 MHz Symbol en Input Noise Current Density in Input Noise Voltage A en p-p Slew Rate SR Gain Bandwidth Product GBW Conditions -6- REV. B Typical Performance Characteristics- OP37 VOLTAGE NOISE - nV/ Hz 90 70 60 50 TEST TIME OF 10sec MUST BE USED TO LIMIT LOW FREQUENCY (<0.1Hz) GAIN. 40 741 5 4 3 I/F CORNER = 2.7Hz 2 0.1 1 10 FREQUENCY - Hz I/F CORNER 10 I/F CORNER = LOW NOISE 2.7Hz AUDIO OP AMP OP37 I/F CORNER INSTRUMENTATION AUDIO RANGE RANGE TO DC TO 20kHz 1 1 30 0.01 10 100 FREQUENCY - Hz 1 100 TPC 1. Noise-Tester Frequency Response (0.1 Hz to 10 Hz) 1 1k TPC 2. Voltage Noise Density vs. Frequency TOTAL NOISE - nV/ Hz 1 0.1 1k 5 R1 TA = 25C VS = 15V TA = 25C VS = 15V 10 100 FREQUENCY - Hz TPC 3. A Comparison of Op Amp Voltage Noise Spectra 100 10 RMS VOLTAGE NOISE - V TA = 25C VS = 15V VS = 15V R2 VOLTAGE NOISE - nV/ Hz GAIN - dB 80 100 10 9 8 7 6 VOLTAGE NOISE - nV/ Hz 100 RS - 2R1 10 AT 10Hz AT 1kHz 4 AT 10Hz 3 AT 1kHz 2 RESISTOR NOISE ONLY 1k 10k BANDWIDTH - Hz 100k TPC 4. Input Wideband Voltage Noise vs. Bandwidth (0.1 Hz to Frequency Indicated) 1k SOURCE RESISTANCE - 1 -50 10k TPC 5. Total Noise vs. Source Resistance 4 AT 10Hz AT 1kHz 3 2 0 10 20 30 40 1.0 TOTAL SUPPLY VOLTAGE (V+ - V-) - Volts TPC 7. Voltage Noise Density vs. Supply Voltage REV. B 0.1 10 0 25 50 75 TEMPERATURE - C 100 125 5.0 4.0 TA = +125C 3.0 TA = -55C 2.0 TA = +25C I/F CORNER = 140Hz 1 -25 TPC 6. Voltage Noise Density vs. Temperature 10.0 TA = 25C CURRENT NOISE - pA/ Hz VOLTAGE NOISE - nV/ Hz 5 1 100 SUPPLY CURRENT - mA 0.01 100 1.0 100 1k FREQUENCY - Hz 10k TPC 8. Current Noise Density vs. Frequency -7- 5 15 25 35 TOTAL SUPPLY VOLTAGE - Volts 45 TPC 9. Supply Current vs. Supply Voltage OP37 OP37A 10 OP37B OP37A 0 -10 OP37A -20 -30 -40 OP37B TRIMMING WITH -50 10k POT DOES NOT CHANGE -60 TCV OS OP37C -70 -75 -50 -25 0 25 50 75 100 125 150 175 TEMPERATURE - C 4 2 0 -2 -4 -6 6 4 2 0 -2 -4 -6 0 1 2 3 4 5 15 10 DEVICE IMMERSED IN 70C OIL BATH 40 40 30 OP37C 20 10 OP37B 60 80 -50 -25 80 60 40 20 102 103 104 105 106 FREQUENCY - Hz 107 108 TPC 16. Open-Loop Gain vs. Frequency PHASE MARGIN - DEG 100 10 OP37C 10 OP37B OP37A 0 25 50 75 0 -75 -50 100 125 150 80 30 90 VS = 15V 75 M 85 70 80 65 75 60 70 GBW 55 65 60 55 25 20 50 SLEW 45 15 10 -50 -25 0 25 50 75 100 100 60 40 125 TEMPERATURE - C TPC 17. Slew Rate, Gain Bandwidth Product, Phase Margin vs. Temperature -8- -25 0 25 50 75 TEMPERATURE - C 125 TPC 15. Input Offset Current vs. Temperature TPC 14. Input Bias Current vs. Temperature SLEW RATE - V/s OPEN-LOOP VOLTAGE GAIN - dB TA = 25C VS = 15V RL 2k 5 20 TEMPERATURE - C 140 4 3 30 0 100 TPC 13. Offset Voltage Change Due to Thermal Shock 1 2 40 OP37A TIME - Seconds 120 1 VS = 15V -80 TA = 25C VS = 15V 50 30 -100 -120 40 GAIN - dB 20 0 50 GAIN-BANDWIDTH PRODUCT - MHz F = 10kHz 0 1 OP37A/E TPC 12. Warm Up Offset Voltage Drift INPUT OFFSET CURRENT - nA INPUT BIAS CURRENT - nA OPEN-LOOP GAIN - dB TA = 70C THERMAL SHOCK RESPONSE BAND 0 -20 5 VS = +15V 25 5 OP37F TIME AFTER POWER ON - MINUTES 50 VS = +15V 20 OP37C/G 7 TPC 11. Long-Term Offset Voltage Drift of Six Representative Units 30 TA = 25C 10 TIME - MONTHS TPC 10. Offset Voltage Drift of Eight Representative Units vs. Temperature 0 6 TA = 25C VS = 15V PHASE MARGIN = 71 -140 -160 20 AV = 5 10 -180 0 -200 -10 100k 1M 10M FREQUENCY - Hz -220 100M TPC 18. Gain, Phase Shift vs. Frequency REV. B PHASE SHIFT - Degrees 30 20 CHANGE IN OFFSET VOLTAGE - V OP37B 40 OFFSET VOLTAGE - V 6 OP37C CHANGE IN INPUT OFFSET VOLTAGE - V 60 50 OP37 2.5 18 28 TA = 25C VS = 15V PEAK-TO-PEAK AMPLITUDE - Volts 2.0 RL = 2k 1.5 RL = 1k 1.0 0.5 0 0 10 20 30 40 24 20 16 12 8 4 0 104 50 POSITIVE SWING 14 12 NEGATIVE SWING 10 8 6 4 2 TA = 25C VS = 15V 0 105 106 FREQUENCY - Hz TOTAL SUPPLY VOLTAGE - Volts TPC 19. Open-Loop Voltage Gain vs. Supply Voltage 16 MAXIMUM OUTPUT - Volts OPEN-LOOP GAIN - V/V TA = 25C -2 100 107 TPC 20. Maximum Output Swing vs. Frequency 1k LOAD RESISTANCE - 10k TPC 21. Maximum Output Voltage vs. Load Resistance 80 1s PERCENT OVERSHOOT 5V 60 0V 0 500 1000 1500 0V TA = 25C VS = 15V AV = +5 (1k, 250) -10V VS = 15V VIN = 20mV AV = +5 (1k, 250) 20 0 +50mV +10V 40 200ns 20mV TA = 25C VS = 15V AV = +5 (1k, 250) -50mV 2000 CAPACITIVE LOAD - pF TPC 22. Small-Signal Overshoot vs. Capacitive Load 16 120 40 CMRR - dB 50 100 ISC(+) 30 COMMON-MODE RANGE - Volts VS = 15V TA = 25C VCM = 10V TA = 25C VS = 15V 80 ISC(-) 60 20 10 TPC 24. Small-Signal Transient Response 140 60 SHORT-CIRCUIT CURRENT - mA TPC 23. Large-Signal Transient Response 0 1 2 3 4 5 TIME FROM OUTPUT SHORTED TO GROUND - MINUTES TPC 25. Short-Circuit Current vs. Time REV. B 40 1k 10k 100k 1M FREQUENCY - Hz 10M TPC 26. CMRR vs. Frequency -9- TA = -55C 12 TA = +25C 8 TA = +125C 4 0 TA = -55C -4 TA = +25C -8 TA = +125C -12 -16 0 5 10 15 20 SUPPLY VOLTAGE - Volts TPC 27. Common-Mode Input Range vs. Supply Voltage OP37 2.4 0.1F OPEN-LOOP VOLTAGE GAIN - V/V 1 SEC/DIV 100k OP37 10 D.U.T. 2k VOLTAGE GAIN = 50,000 4.3k 22F OP12 SCOPE 1 RIN = 1M 4.7F 100k 2.2F 110k 0.1F TPC 28. Noise Test Circuit (0.1 Hz to 10 Hz) TPC 29. Low-Frequency Noise TA = 25C VS = 15V AV = 5 VO = 20V p-p 1.6 1.4 1.2 1.0 0.8 0.6 100 NEGATIVE SWING 60 POSITIVE SWING 1k 10k LOAD RESISTANCE - TA = 25C AVCL = 5 VOLTAGE NOISE - V/s 18 120 SLEW RATE - V/V POWER SUPPLY REJECTION RATIO - dB 1.8 100k 20 TA = 25C 40 2.0 TPC 30. Open-Loop Voltage Gain vs. Load Resistance 19 160 80 TA = 25C VS = 15V 0.4 100 24.3k 140 2.2 17 16 RISE 15 FALL 10 5 20 0 1 10 100 1k 10k 100k 1M 10M 100M FREQUENCY - Hz TPC 31. PSRR vs. Frequency 15 100 1k 10k LOAD RESISTANCE - TPC 32. Slew Rate vs. Load -10- 100k 0 3 6 9 12 15 18 SUPPLY VOLTAGE - Volts 21 TPC 33. Slew Rate vs. Supply Voltage REV. B OP37 APPLICATIONS INFORMATION Noise Measurements OP37 Series units may be inserted directly into 725 and OP07 sockets with or without removal of external compensation or nulling components. Additionally, the OP37 may be fitted to unnulled 741type sockets; however, if conventional 741 nulling circuitry is in use, it should be modified or removed to ensure correct OP37 operation. OP37 offset voltage may be nulled to zero (or other desired setting) using a potentiometer (see figure 1). To measure the 80 nV peak-to-peak noise specification of the OP37 in the 0.1 Hz to 10 Hz range, the following precautions must be observed: The OP37 provides stable operation with load capacitances of up to 1000 pF and 10 V swings; larger capacitances should be decoupled with a 50 W 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 OP27 and the OP37. For gains above ten, the OP37 has a clear advantage over the unity stable OP27. Thermoelectric voltages generated by dissimilar metals at the input terminal contacts can degrade the drift performance. Best operation will be obtained when both input contacts are maintained at the same temperature. 10k RP V+ - OP37 OUTPUT + For similar reasons, the device has to be well-shielded from air currents. Shielding minimizes thermocouple effects. Sudden motion in the vicinity of the device can also "feedthrough" to increase the observed noise. The test time to measure 0.1 Hz to l0 Hz noise should not exceed 10 seconds. As shown in the noise-tester frequency response curve, the 0.1 Hz corner is defined by only one zero. The test time of ten seconds acts as an additional zero to eliminate noise contributions from the frequency band below 0.1 Hz. A noise-voltage-density test is recommended when measuring noise on a large number of units. A 10 Hz noise-voltage-density measurement will correlate well with a 0.1 Hz-to-10 Hz 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 V- Figure 1. Offset Nulling Circuit Offset Voltage Adjustment The input offset voltage of the OP37 is trimmed at wafer level. However, if further adjustment of VOS is necessary, a 10 kW trim potentiometer may be used. TCVOS is not degraded (see offset nulling circuit). Other potentiometer values from 1 kW to 1 MW can be used with a slight degradation (0.1 mV/C to 0.2 mV/C) of TCVOS. Trimming to a value other than zero creates a drift of approximately (VOS/300) mV/C. For example, the change in TCVOS will be 0.33 mV/C if VOS is adjusted to 100 mV. The offset voltage adjustment range with a 10 kW potentiometer is 4 mV. If smaller adjustment range is required, the nulling sensitivity can be reduced by using a smaller pot in conjunction with fixed resistors. For example, the network shown in figure 2 will have a 280 mV adjustment range. 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 4 mV due to increasing chip temperature after power up. In the ten second measurement interval, these temperatureinduced effects can exceed tens of nanovolts. 4.7k 1k POT 4.7k 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 10 mA. Instrumentation Amplifier A three-op-amp instrumentation amplifier, shown in figure 4, provides high gain and wide bandwidth. The input noise of the circuit below is 4.9 nV//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 800 kHz is extraordinarily good for a precision instrumentation amplifier. Set to a gain of 1000, this yields a gain bandwidth product of 800 MHz. The full-power bandwidth for a 20 V p-p output is 250 kHz. Potentiometer R7 provides quadrature trimming to optimize the instrumentation amplifier's ac common-mode rejection. INPUT (-) + OP37 - R1 8 R8 20k 0.1% 5k 0.1% R3 390 V+ Figure 2. Offset Voltage Adjustment R4 5k 0.1% R2 100 +18V - INPUT (+) OP37 + C1 100pF R6 500 0.1% R7 100k - VOUT OP37 + R9 19.8k R10 500 NOTES: TRIM R2 FOR AVCL = 1000 TRIM R10 FOR dc CMRR TRIM R7 FOR MINIMUM V OUT AT V CM = 20V p-p, 10kHz OP37 Figure 4a. Instrumentation Amplifier -18V Figure 3. Burn-In Circuit REV. B R5 500 0.1% -11- OP37 1k 140 TA = 25C VS = 15V VCM = 20V p-p AC TRIM @ 10kHz RS = 0 RS = 0 120 OP08/108 500 5534 p-p NOISE - nV CMRR - dB OP07 100 RS = 1k BALANCED 80 RS = 100, 1k UNBALANCED 1 2 100 OP27/37 1 RS e.g. RS 2 RS e.g. RS 50 60 UNMATCHED = R S1 = 10k, R S2 = 0 MATCHED = 10k, R S1 = R S2 = 5k RS1 RS2 REGISTER NOISE ONLY 40 10 100 1k 10k FREQUENCY - Hz 100k 10 50 1M Figure 4b. CMRR vs. Frequency 10k 500 1k 5k RS - SOURCE RESISTANCE - 100 Figure 6. Peak-to-Peak Noise (0.1 Hz to 10 Hz) vs. Source Resistance (Includes Resistor Noise) Comments on Noise The OP37 is a very low-noise monolithic op amp. The outstanding input voltage noise characteristics of the OP37 are achieved mainly by operating the input stage at a high quiescent current. The input bias and offset currents, which would normally increase, are held to reasonable values by the input bias current cancellation circuit. The OP37A/E has IB and IOS of only 40 nA and 35 nA respectively at 25C. This is particularly important when the input has a high source resistance. In addition, many audio amplifier designers prefer to use direct coupling. The high IB. TCVOS of previous designs have made direct coupling difficult, if not impossible, to use. At RS < 1 kW key the OP37's low voltage noise is maintained. With RS < 1 kW, total noise increases, but is dominated by the resistor noise rather than current or voltage noise. It is only beyond Rs of 20 kW that current noise starts to dominate. The argument can be made that current noise is not important for applications with low to-moderate source resistances. The crossover between the OP37 and OP07 and OP08 noise occurs in the 15 kW to 40 kW region. 100 50 1 2 TOTAL NOISE - nV/ Hz 100 50 1 TOTAL NOISE - nV/ Hz 50k OP08/108 2 OP07 10 OP08/108 10 OP07 5534 1 RS e.g. RS 2 RS e.g. RS 5 OP27/37 UNMATCHED = R S1 = 10k, R S2 = 0 MATCHED = 10k, R S1 = R S2 = 5k RS1 5 1 RS e.g. RS 2 RS e.g. RS 5534 OP27/37 1 50 REGISTER NOISE ONLY 1 50 RS1 REGISTER NOISE ONLY 100 UNMATCHED = R S1 = 10k, R S2 = 0 MATCHED = 10k, R S1 = R S2 = 5k RS2 500 1k 5k 10k RS - SOURCE RESISTANCE - 100 RS2 10k 500 1k 5k RS - SOURCE RESISTANCE - 50k Figure 7. Noise vs. Source resistance (Includes Resistor Noise @ 10 Hz) 50k Figure 5. Noise vs. Resistance (Including Resistor Noise @ 1000 Hz) 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 OP37's noise advantage disappears when high source-resistors are used. Figures 5, 6, and 7 compare OP-37 observed total noise with the noise performance of other devices in different circuit applications. Total noise = [( Voltage noise)2 + (current noise RS)2 + (resistor noise_]1/2 Figure 5 shows noise versus source resistance at 1000 Hz. The same plot applies to wideband noise. To use this plot, just multiply the vertical scale by the square-root of the bandwidth. Figure 6 shows the 0.1 Hz to 10 Hz peak-to-peak noise. Here the picture is less favorable; resistor noise is negligible, current noise becomes important because it is inversely proportional to the square-root of frequency. The crossover with the OP07 occurs in the 3 kW to 5 kW range depending on whether balanced or unbalanced source resistors are used (at 3 kW the IB. IOS error also can be three times the VOS spec.). Therefore, for low-frequency applications, the OP07 is better than the OP27/37 when Rs > 3 kW. The only exception is when gain error is important. Figure 7 illustrates the 10 Hz noise. As expected, the results are between the previous two figures. For reference, typical source resistances of some signal sources are listed in Table I. -12- REV. B OP37 by only 0.7 dB. With a 1 kW source, the circuit noise measures 63 dB below a 1 mV reference level, unweighted, in a 20 kHz noise bandwidth. Table I. Device Source Impedance Straln Gauge <500 W Magnetic Tapehead <1500 W Comments Gain (G) of the circuit at 1 kHz can be calculated by the expression: Typically used in low-frequency applications. Low IB very important to reduce set-magnetization problems when direct coupling is used. OP37 IB can be neglected. Similar need for low IB in direct coupled applications. OP37 will not introduce any self-magnetization problem. Used in rugged servo-feedback applications. Bandwidth of interest is 400 Hz to 5 kHz. For the values shown, the gain is just under 100 (or 40 dB). Lower gains can be accommodated by increasing R3, but gains higher than 40 dB will show more equalization errors because of the 8 MHz gain bandwidth of the OP27. The following applications information has been abstracted from a PMI article in the 12/20/80 issue of Electronic Design magazine and updated. Capacitor C3 and resistor R4 form a simple -6 dB per octave rumble filter, with a corner at 22 Hz. As an option, the switch selected shunt capacitor C4, a nonpolarized electrolytic, bypasses the low-frequency rolloff. Placing the rumble filter's 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. <1500 W Magnetic Phonograph Cartridges Linear Variable <1500 W Differential Transformer Audio Applications C4 (2) 220F + + MOVING MAGNET CARTRIDGE INPUT Ra 47.5k Ca 150pF A1 OP27 C3 0.47F R1 97.6k R5 100k LF ROLLOFF OUT R4 75k IN OUTPUT E R G = 0.101 A1 + 1 R3 E This circuit is capable of very low distortion over its entire range, generally below 0.01% at levels up to 7 V rms. At 3 V output levels, it will produce less than 0.03% total harmonic distortion at frequencies up to 20 kHz. 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 Figure 8 can be readily modified for tape use, as shown by Figure 9. C1 0.03F - R2 7.87k C2 0.01F TAPE HEAD Ra Ca 0.47F OP37 + R1 33k R3 100 R2 5k G = 1kHz GAIN R1 = 0.101 ( 1 + ) R3 = 98.677 (39.9dB) AS SHOWN 100k 15k 0.01F T1 = 3180s T2 = 50s Figure 8. Phono Pre-Amplifier Circuit Figure 8 is an example of a phono pre-amplifier circuit using the OP27 for A1; R1-R2-C1-C2 form a very accurate RIAA network with standard component values. The popular method to accomplish RIAA phono equalization is to employ frequencydependent feedback around a high-quality gain block. Properly chosen, an RC network can provide the three necessary time constants of 3180 ms, 318 ms, and 75 ms.1 For initial equalization accuracy and stability, precision metalfilm 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 OP37 brings a 3.2 nV//Hz voltage noise and 0.45 pA//Hz current noise to this circuit. To minimize noise from other sources, R3 is set to a value of 100 W, which generates a voltage noise of 1.3 nV//Hz. The noise increases the 3.2 nV//Hz of the amplifier REV. B Figure 9. Tape-Head Preamplifier While the tape-equalization requirement has a flat high frequency gain above 3 kHz (t2 = 50 ms), the amplifier need not be stabilized for unity gain. The decompensated OP37 provides a greater bandwidth and slew rate. For many applications, the idealized time constants shown may require trimming of Ra and R2 to optimize frequency response for non ideal tape head performance and other factors.5 The network values of the configuration yield a 50 dB gain at 1 kHz, and the dc gain is greater than 70 dB. Thus, the worst-case output offset is just over 500 mV. A single 0.47 mF 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 85 nA with a 400 mH, 100 min. head (such as the PRB2H7K) will not be troublesome. One potential tape-head problem is presented by amplifier biascurrent transients which can magnetize a head. The OP27 and -13- OP37 OP37 are free of bias-current transients upon power up or power down. However, it is always advantageous to control the speed of power supply rise and fall, to eliminate transients. Gain may be trimmed to other levels, if desired, by adjusting R2 or R1. Because of the low offset voltage of the OP27, the output offset of this circuit will be very low, 1.7 mV or less, for a 40 dB gain. The typical output blocking capacitor can be eliminated in such cases, but is desirable for higher gains to eliminate switching transients. In addition, the dc resistance of the head should be carefully controlled, and preferably below 1 kW. For this configuration, the bias-current induced offset voltage can be greater than the 170 pV maximum offset if the head resistance is not sufficiently controlled. C2 1800pF A simple, but effective, fixed-gain transformerless microphone preamp (Figure 10) amplifies differential signals from low impedance microphones by 50 dB, and has an input impedance of 2 kW. Because of the high working gain of the circuit, an OP37 helps to preserve bandwidth, which will be 110 kHz. As the OP37 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% feedback from the open input may cause the amplifier to oscillate. R1 1k C1 5F Rp 30k R2 1k OP37 + 150 SOURCE R7 10k R2 1100 A1 OP27 T1* R3 100 OUTPUT * T1 - JENSEN JE - 115K - E JENSEN TRANSFORMERS 10735 BURBANK BLVD. N. HOLLYWOOD, CA 91601 R6 100 Figure 11. Microphone Transformer Coupled Preamp Capacitor C2 and resistor R2 form a 2 ms time constant in this circuit, as recommended for optimum transient response by the transformer manufacturer. With C2 in use, A1 must have unity-gain stability. For situations where the 2 ms time constant is not necessary, C2 can be deleted, allowing the faster OP37 to be employed. - LOW IMPEDANCE MICROPHONE INPUT (Z = 50 TO 200 ) R3 = R4 R1 R2 R3 316k R1 121 OUTPUT R4 316k Figure 10. Fixed Gain Transformerless Microphone Preamp 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 stability and low noise. Noise performance of this circuit is limited more by the input resistors R1 and R2 than by the op amp, as R1 and R2 each generate a 4 nV//Hz noise, while the op amp generates a 3.2 nV/ /Hz noise. The rms sum of these predominant noise sources will be about 6 nV//Hz, equivalent to 0.9 mV in a 20 kHz noise bandwidth, or nearly 61 dB below a l mV input signal. Measurements confirm this predicted performance. For applications demanding appreciably lower noise, a high quality microphone-transformer-coupled preamp (Figure 11) incorporates the internally compensated. T1 is a JE-115K-E 150 W/15 kW transformer which provides an optimum source resistance for the OP27 device. The circuit has an overall gain of 40 dB, the product of the transformer's voltage setup and the op amp's voltage gain. Some comment on noise is appropriate to understand the capability of this circuit. A 150 W resistor and R1 and R2 gain resistors connected to a noiseless amplifier will generate 220 nV of noise in a 20 kHz bandwidth, or 73 dB below a 1 mV reference level. Any practical amplifier can only approach this noise level; it can never exceed it. With the OP27 and T1 specified, the additional noise degradation will be close to 3.6 dB (or -69.5 referenced to 1 mV). References 1. Lipshitz, S.P, "On RIAA Equalization Networks," JAES, Vol. 27, June 1979, p. 458-4S1. 2. Jung, W.G., IC Op Amp Cookbook, 2nd Ed., H.W. Sams and Company, 1980. 3. Jung, W.G., Audio /C Op Amp Applications, 2nd Ed., H.W. Sams and Company, 1978. 4. Jung, W.G., and Marsh, R.M., "Picking Capacitors." Audio, February & March, 1980. 5. Otala, M., "Feedback-Generated Phase Nonlinearity in Audio Amplifiers," London AES Convention, March 1980, preprint 197B. 6. Stout, D.F., and Kaufman, M., Handbook of Operational Amplifier Circuit Design, New York, McGraw Hill, 1976. -14- REV. B OP37 OUTLINE DIMENSIONS 8-Lead Ceramic DIP - Glass Hermetic Seal [CERDIP] (Q-8) Dimensions shown in inches and (millimeters) 0.055 (1.40) MAX 0.005 (0.13) MIN 8 5 0.310 (7.87) 0.220 (5.59) PIN 1 1 4 0.100 (2.54) BSC 0.320 (8.13) 0.290 (7.37) 0.405 (10.29) MAX 0.060 (1.52) 0.015 (0.38) 0.200 (5.08) MAX 0.150 (3.81) MIN 0.200 (5.08) 0.125 (3.18) 0.023 (0.58) 0.014 (0.36) SEATING 0.070 (1.78) PLANE 0.030 (0.76) 0.015 (0.38) 0.008 (0.20) 15 0 CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN 8-Lead Plastic Dual-in-Line Package [PDIP] 8-Lead Standard Small Outline Package [SOIC] (N-8) Narrow Body Dimensions shown in inches and (millimeters) (RN-8) Dimensions shown in millimeters and (inches) 0.375 (9.53) 0.365 (9.27) 0.355 (9.02) 8 5 1 4 5.00 (0.1968) 4.80 (0.1890) 0.295 (7.49) 0.285 (7.24) 0.275 (6.98) 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.100 (2.54) BSC 0.180 (4.57) MAX 0.150 (3.81) 0.130 (3.30) 0.110 (2.79) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.015 (0.38) MIN SEATING PLANE 0.060 (1.52) 0.050 (1.27) 0.045 (1.14) 4.00 (0.1574) 3.80 (0.1497) 0.150 (3.81) 0.135 (3.43) 0.120 (3.05) 5 1 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 0.015 (0.38) 0.010 (0.25) 0.008 (0.20) COPLANARITY SEATING 0.10 PLANE 6.20 (0.2440) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.33 (0.0130) 0.50 (0.0196) 45 0.25 (0.0099) 8 0.25 (0.0098) 0 1.27 (0.0500) 0.41 (0.0160) 0.19 (0.0075) COMPLIANT TO JEDEC STANDARDS MS-012AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN COMPLIANT TO JEDEC STANDARDS MO-095AA CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN REV. B 8 -15- OP37 Revision History Location Page 12/02-Data Sheet changed from REV. A to REV. B. Edits to Caption for TPC 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Edits to APPLICATIONS INFORMATION Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Added Caption to Figure 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Added Caption to Figures 4a and 4b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Added Caption to Figures 8-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 C00319-0-12/02(B) Edits to BINDING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/02-Data Sheet changed from REV. 0 to REV. A. Edits to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Edits to ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Edits to PIN CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Edits to ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Edits to PACKAGE TYPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Edits to ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 PRINTED IN U.S.A. Edits to APPLICATIONS INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 -16- REV. B