Low Noise, Precision Operational Amplifier OP27 PIN CONFIGURATIONS FEATURES Low noise: 80 nV p-p (0.1 Hz to 10 Hz), 3 nV/Hz Low drift: 0.2 V/C High speed: 2.8 V/s slew rate, 8 MHz gain bandwidth Low VOS: 10 V Excellent CMRR: 126 dB at VCM of 11 V High open-loop gain: 1.8 million Fits OP07, 5534A sockets Available in die form BAL BAL 1 OP27 V+ OUT -IN 2 00317-001 NC +IN 3 4V- (CASE) NC = NO CONNECT Figure 1. 8-Lead TO-99 (J-Suffix) GENERAL DESCRIPTION VOS TRIM 1 OP27 8 VOS TRIM -IN 2 7 V+ +IN 3 6 OUT V- 4 5 NC 00317-002 The OP27 precision operational amplifier combines the low offset and drift of the OP07 with both high speed and low noise. Offsets down to 25 V and maximum drift of 0.6 V/C make the OP27 ideal for precision instrumentation applications. Exceptionally low noise, en = 3.5 nV/Hz, at 10 Hz, a low 1/f noise corner frequency of 2.7 Hz, and high gain (1.8 million), allow accurate high-gain amplification of low-level signals. A gain-bandwidth product of 8 MHz and a 2.8 V/s slew rate provide excellent dynamic accuracy in high speed, dataacquisition systems. NC = NO CONNECT Figure 2. 8-Lead CERDIP - Glass Hermetic Seal (Z-Suffix), 8-Lead PDIP (P-Suffix), 8-Lead SO (S-Suffix) A low input bias current of 10 nA is achieved by use of a bias current cancellation circuit. Over the military temperature range, this circuit typically holds IB and IOS to 20 nA and 15 nA, respectively. The output stage has good load driving capability. A guaranteed swing of 10 V into 600 and low output distortion make the OP27 an excellent choice for professional audio applications. (Continued on Page 3) FUNCTIONAL BLOCK DIAGRAM V+ R3 Q6 R11 1 8 VOS ADJ.. C2 R4 Q22 R21 R23 Q21 Q24 Q23 Q46 C1 R24 R9 Q20 Q1A Q1B Q2B Q19 OUTPUT R12 Q2A NONINVERTING INPUT (+) C3 R5 C4 Q3 INVERTING INPUT (-) Q11 Q26 Q12 Q27 Q45 Q28 AND R2 ARE PERMANENTLY ADJUSTED AT WAFER TEST FOR MINIMUM OFFSET VOLTAGE V- 00317-003 1 R1 Figure 3. Rev. F 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. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 (c)2006 Analog Devices, Inc. All rights reserved. OP27 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................8 General Description ......................................................................... 1 Application Information................................................................ 14 Pin Configurations ........................................................................... 1 Offset Voltage Adjustment ........................................................ 14 Functional Block Diagram .............................................................. 1 Noise Measurements.................................................................. 14 Revision History ............................................................................... 2 Unity-Gain Buffer Applications ............................................... 14 Specifications..................................................................................... 4 Comments On Noise ................................................................. 15 Electrical Characteristics............................................................. 4 Audio Applications .................................................................... 16 Typical Electrical Characteristics ............................................... 6 References.................................................................................... 18 Absolute Maximum Ratings............................................................ 7 Outline Dimensions ....................................................................... 19 Thermal Resistance ...................................................................... 7 Ordering Guide............................................................................... 20 ESD Caution.................................................................................. 7 REVISION HISTORY 5/06--Rev. E to Rev. F Removed References to 745 ..............................................Universal Updated 741 to AD741 ......................................................Universal Changes to Ordering Guide .......................................................... 20 12/05--Rev. D to Rev. E Edits to Figure 2 ................................................................................ 1 9/05--Rev. C to Rev. D Updated Format..................................................................Universal Changes to Table 1............................................................................ 4 Removed Die Characteristics Figure ............................................ 5 Removed Wafer Test Limits Table .................................................. 5 Changes to Table 5............................................................................ 7 Changes to Comments on Noise Section .................................... 15 Changes to Ordering Guide .......................................................... 24 9/01--Rev. 0 to Rev. A 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 .............................................. 2, 3 Edits to Wafer Test Limits ................................................................4 Deleted Typical Electrical Characteristics......................................4 Edits to Burn-In Circuit Figure .......................................................7 Edits to Application Information ....................................................8 1/03--Rev. B to Rev. C Edits to Pin Connections................................................................. 1 Edits to General Description........................................................... 1 Edits to Die Characteristics............................................................. 5 Edits to Absolute Maximum Ratings ............................................. 7 Updated Outline Dimensions ....................................................... 16 Edits to Figure 8 .............................................................................. 14 Edits to Outline Dimensions......................................................... 16 Rev. F | Page 2 of 20 OP27 GENERAL DESCRIPTION (Continued from Page 1) PSRR and CMRR exceed 120 dB. These characteristics, coupled with long-term drift of 0.2 V/month, allow the circuit designer to achieve performance levels previously attained only by discrete designs. Low cost, high volume production of OP27 is achieved by using an on-chip Zener zap-trimming network. This reliable and stable offset trimming scheme has proven its effectiveness over many years of production history. The OP27 provides excellent performance in low noise, high accuracy amplification of low level signals. Applications include stable integrators, precision summing amplifiers, precision voltage threshold detectors, comparators, and professional audio circuits such as tape heads and microphone preamplifiers. The OP27 is a direct replacement for OP06, OP07, and OP45 amplifiers; AD741 types can be directly replaced by removing the nulling potentiometer of the AD741. Rev. F | Page 3 of 20 OP27 SPECIFICATIONS ELECTRICAL CHARACTERISTICS VS = 15 V, TA = 25C, unless otherwise noted. Table 1. Parameter INPUT OFFSET VOLTAGE 1 LONG-TERM VOS STABILITY 2, 3 INPUT OFFSET CURRENT INPUT BIAS CURRENT INPUT NOISE VOLTAGE3, 4 INPUT NOISE Voltage Density3 Symbol VOS VOS/Time IOS IB en p-p en INPUT NOISE Current Density3 in INPUT RESISTANCE Differential Mode 5 Common Mode INPUT VOLTAGE RANGE COMMON-MODE REJECTION RATIO POWER SUPPLY REJECTION RATIO LARGE SIGNAL VOLTAGE GAIN RIN RINCM IVR CMRR PSRR AVO OUTPUT VOLTAGE SWING VO SLEW RATE 6 GAIN BANDWIDTH PRODUCT6 OPEN-LOOP OUTPUT RESISTANCE POWER CONSUMPTION OFFSET ADJUSTMENT RANGE SR GBW RO Pd Conditions Min 0.1 Hz to 10 Hz fO = 10 Hz fO = 30 Hz fO = 1000 Hz fO = 10 Hz fO = 30 Hz fO = 1000 Hz 1.3 VCM = 11 V VS = 4 V to 18 V RL 2 k , VO = 10 V RL 600 , VO = 10 V RL 2 k RL 600 RL 2 k VO = 0, IO = 0 VO RP = 10 k 1 11.0 114 1000 800 12.0 10.0 1.7 5.0 OP27A/E Typ 10 0.2 7 10 0.08 3.5 3.1 3.0 1.7 1.0 0.4 6 3 12.3 126 1 1800 1500 13.8 11.5 2.8 8.0 70 90 4.0 Max 25 1.0 35 40 0.18 5.5 4.5 3.8 4.0 2.3 0.6 Min 0.7 11.0 100 10 700 600 11.5 10.0 1.7 5.0 140 OP27/G Typ 30 0.4 12 15 0.09 3.8 3.3 3.2 1.7 1.0 0.4 4 2 12.3 120 2 1500 1500 13.5 11.5 2.8 8.0 70 100 4.0 Max 100 2.0 75 80 0.25 8.0 5.6 4.5 0.6 20 170 Unit V V/MO nA nA V p-p nV/Hz nV/Hz nV/Hz pA/Hz pA/Hz pA/Hz M G V dB V/V V/mV V/mV V V V/s MHz mW mV Input offset voltage measurements are performed 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 VOS vs. time over extended periods after the first 30 days of operation. Excluding the initial hour of operation, changes in VOS during the first 30 days are typically 2.5 V. Refer to the Typical Performance Characteristics section. 3 Sample tested. 4 See voltage noise test circuit (Figure 31). 5 Guaranteed by input bias current. 6 Guaranteed by design. 2 Rev. F | Page 4 of 20 OP27 VS = 15 V, -55C TA 125C, unless otherwise noted. Table 2. Parameter INPUT OFFSET VOLTAGE 1 AVERAGE INPUT OFFSET DRIFT Symbol VOS TCVOS 2 TCVOSn 3 IOS IB IVR CMRR PSRR AVO VO INPUT OFFSET CURRENT INPUT BIAS CURRENT INPUT VOLTAGE RANGE COMMON-MODE REJECTION RATIO POWER SUPPLY REJECTION RATIO LARGE SIGNAL VOLTAGE GAIN OUTPUT VOLTAGE SWING Conditions VCM = 10 V VS = 4.5 V to 18 V RL 2 k, VO = 10 V RL 2 k Min OP27A Typ 30 10.3 108 0.2 15 20 11.5 122 2 1200 13.5 600 11.5 Max 60 Unit V 0.6 50 60 V/C nA nA V dB V/V V/mV V 16 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 TCVOS performance is within the specifications unnulled or when nulled with RP = 8 k to 20 k. TCVOS is 100% tested for A/E grades, sample tested for G grades. 3 Guaranteed by design. VS = 15 V, -25C TA 85C for OP27J, OP27Z, 0C TA 70C for OP27EP, and -40C TA 85C for OP27GP, OP27GS, unless otherwise noted. Table 3. Parameter INPUT ONSET 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 1 2 Symbol VOS TCVOS 1 TCVOSn 2 IOS IB IVR CMRR PSRR AVO VO Conditions VCM = 10 V VS = 4.5 V to 18 V RL 2 k, VO = 10 V RL 2 k Min 10.5 110 750 11.7 OP27E Typ 20 0.2 0.2 10 14 11.8 124 2 1500 13.6 Max 50 0.6 0.6 50 60 Min 10.5 96 15 450 11.0 OP27G Typ 55 04 04 20 25 11.8 118 2 1000 13.3 Max 220 1.8 1.8 135 150 32 Unit V V/C V/C nA nA V dB V/V V/mV V The TCVOS performance is within the specifications unnulled or when nulled with RP = 8 k to 20 k. TCVOS is 100% tested for A/E grades, sample tested for C/G grades. Guaranteed by design. Rev. F | Page 5 of 20 OP27 TYPICAL ELECTRICAL CHARACTERISTICS VS = 15 V, TA = 25C unless otherwise noted. Table 4. Parameter AVERAGE INPUT OFFSET VOLTAGE DRIFT 1 AVERAGE INPUT OFFSET CURRENT DRIFT AVERAGE INPUT BIAS CURRENT DRIFT INPUT NOISE VOLTAGE DENSITY INPUT NOISE CURRENT DENSITY INPUT NOISE VOLTAGE SLEW RATE GAIN BANDWIDTH PRODUCT 1 Symbol TCVOS or TCVOSn TCIOS TCIB en en en Conditions Nulled or unnulled RP = 8 k to 20 k in in in enp-p SR GBW fO = 10 Hz fO = 30 Hz fO = 1000 Hz 0.1 Hz to 10 Hz RL 2 k fO = 10 Hz fO = 30 Hz fO = 1000 Hz OP27N Typical 0.2 Unit V/C 80 100 3.5 3.1 3.0 pA/C pA/C nV/Hz nV/Hz nV/Hz 1.7 1.0 0.4 0.08 2.8 8 pA/Hz pA/Hz pA/Hz V p-p V/s MHz Input offset voltage measurements are performed by automated test equipment approximately 0.5 seconds after application of power. Rev. F | Page 6 of 20 OP27 ABSOLUTE MAXIMUM RATINGS Table 5. Parameter Supply Voltage Input Voltage 1 Output Short-Circuit Duration Differential Input Voltage 2 Differential Input Current2 Storage Temperature Range Operating Temperature Range OP27A (J, Z) OP27E, ( Z) OP27E, (P) OP27G (P, S, J, Z) Lead Temperature Range (Soldering, 60 sec) Junction Temperature Rating 22 V 22 V Indefinite 0.7 V 25 mA -65C to +150C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. THERMAL RESISTANCE -55C to +125C -25C to +85C 0C to 70C -40C to +85C 300C -65C to +150C JA is specified for the worst-case conditions, that is, JA is specified for device in socket for TO, CERDIP, and PDIP packages; JA 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. 1 For supply voltages less than 22 V, the absolute maximum input voltage is equal to the supply voltage. 2 The inputs of the OP27 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. Table 6. Package Type TO-99 (J) 8-Lead Hermetic DlP (Z) 8-Lead Plastic DIP (P) 8-Lead SO (S) JA 150 148 103 158 ESD 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 this product 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. Rev. F | Page 7 of 20 JC 18 16 43 43 Unit C/W C/W C/W C/W OP27 TYPICAL PERFORMANCE CHARACTERISTICS 100 10 TA = 25C VS = 15V RMS VOLTAGE NOISE (V) 90 70 60 50 0.1 TEST TIME OF 10sec FURTHER LIMITS LOW FREQUENCY (<0.1Hz) GAIN 30 0.01 0.1 1 10 100 FREQUENCY (Hz) 0.01 100 00317-004 40 Figure 4. 0.1 Hz to 10 Hz p-p Noise Tester Frequency Response 1k 10k 100k BANDWIDTH (Hz) Figure 7. Input Wideband Voltage Noise vs. Bandwidth (0.1 Hz to Frequency Indicated) 100 10 9 8 R1 TA = 25C VS = 15V TA = 25C VS = 15V 7 R2 RS - 2R1 6 TOTAL NOISE (nV/Hz) VOLTAGE NOISE (nV/Hz) 1 00317-007 GAIN (dB) 80 5 4 3 I/F CORNER = 2.7Hz 2 10 AT 10Hz AT 1kHz 1 10 100 1k FREQUENCY (Hz) 00317-005 1 1k 10k SOURCE RESISTANCE () 00317-008 RESISTOR NOISE ONLY 1 100 Figure 8. Total Noise vs. Sourced Resistance Figure 5. Voltage Noise Density vs. Frequency 100 5 VS = 15V VOLTAGE NOISE (nV/Hz) I/F CORNER 10 LOW NOISE AUDIO OP AMP OP27 I/F CORNER INSTRUMENTATION RANGE TO DC 1 1 10 4 AT 10Hz 3 AT 1kHz 2 AUDIO RANGE TO 20kHz 100 FREQUENCY (Hz) 1k 1 -50 -25 0 25 50 75 100 TEMPERATURE (C) Figure 6. A Comparison of Op Amp Voltage Noise Spectra Figure 9. Voltage Noise Density vs. Temperature Rev. F | Page 8 of 20 125 00317-009 I/F CORNER = 2.7Hz 00317-006 VOLTAGE NOISE (nV/Hz) 741 OP27 5 60 TA = 25C OP27C 50 OP27A 30 3 AT 1kHz 2 20 10 OP27A 0 -10 OP27A -20 -30 -40 TRIMMING WITH 10k POT DOES NOT CHANGE TCVOS -50 -60 0 10 20 30 40 TOTAL SUPPLY VOLTAGE, V+ - V-, (V) -70 -75 00317-010 1 -50 -25 OP27C 0 25 50 75 100 125 150 175 TEMPERATURE (C) 00317-013 AT 10Hz OFFSET VOLTAGE (V) VOLTAGE NOISE (nV/Hz) 40 4 Figure 13. Offset Voltage Drift of Five Representative Units vs. Temperature Figure 10. Voltage Noise Density vs. Supply Voltage 10.0 6 CHANGE IN OFFSET VOLTAGE (V) CURRENT NOISE (pA/Hz) 4 1.0 I/F CORNER = 140Hz 2 0 -2 -4 -6 6 4 2 0 -2 10k FREQUENCY (Hz) -6 0 CHANGE IN INPUT OFFSET VOLTAGE (V) TA = +125C 3.0 TA = -55C 2.0 TA = +25C 25 35 TOTAL SUPPLY VOLTAGE (V) 45 4 5 6 7 TA = 25C VS = 15V 10 OP27 C/G OP27 F 5 1 00317-012 SUPPLY CURRENT (mA) 4.0 15 3 Figure 14. Long-Term Offset Voltage Drift of Six Representative Units 5.0 5 2 TIME (Months) Figure 11. Current Noise Density vs. Frequency 1.0 1 OP27 A/E 0 1 2 3 4 TIME AFTER POWER ON (Min) Figure 15. Warm-Up Offset Voltage Drift Figure 12. Supply Current vs. Supply Voltage Rev. F | Page 9 of 20 5 00317-015 1k 00317-011 100 00317-014 -4 0.1 10 OP27 30 130 VS = 15V 110 TA = 70C 20 THERMAL SHOCK RESPONSE BAND 50 30 5 10 DEVICE IMMERSED IN 70C OIL BATH 0 20 40 60 100 80 TIME (Sec) -10 00317-016 0 -20 1 10 PHASE MARGIN (Degrees) VS = 15V 30 100k 1M 100M 10M 10 70 M VS = 15V 9 60 GBW 50 8 4 20 SLEW RATE (V/S) OP27C 10 0 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) 00317-017 OP27A 7 2 -75 -50 -25 0 25 50 75 100 6 125 TEMPERATURE (C) Figure 20. Slew Rate, Gain Bandwidth Product, Phase Margin vs. Temperature Figure 17. Input Bias Current vs. Temperature 50 SLEW 3 80 25 VS = 15V TA = 25C VS = 15V 20 40 100 15 GAIN (dB) 30 20 OP27C 10 120 PHASE MARGIN = 70 140 5 160 0 180 -5 200 PHASE SHIFT (Degrees) GAIN 10 0 -75 -50 -25 0 25 50 75 100 TEMPERATURE (C) 125 00317-018 OP27A Figure 18. Input Offset Current vs. Temperature -10 1M 10M FREQUENCY (Hz) Figure 21. Gain, Phase Shift vs. Frequency Rev. F | Page 10 of 20 220 100M 00317-021 INPUT BIAS CURRENT (nA) 10k Figure 19. Open-Loop Gain vs. Frequency 40 INPUT OFFSET CURRENT (nA) 1k FREQUENCY (Hz) Figure 16. Offset Voltage Change Due to Thermal Shock 50 100 00317-019 10 70 GAIN BANDWIDTH PRODUCT (MHz) 15 90 00317-020 TA = 25C VOLTAGE GAIN (dB) OPEN-LOOP GAIN (dB) 25 OP27 2.5 100 TA = 25C 80 RL = 2k % OVERSHOOT 1.5 RL = 1k 1.0 0.5 40 20 0 10 20 30 50 40 TOTAL SUPPLY VOLTAGE (V) 0 00317-022 0 60 1000 1500 2000 2500 Figure 25. Small-Signal Overshoot vs. Capacitive Load TA = 25C VS = 15V 24 MAXIMUM OUTPUT SWING 500 CAPACITIVE LOAD (pF) Figure 22. Open-Loop Voltage Gain vs. Supply Voltage 28 0 20mV 500ns 20 50mV AVCL = +1 CL = 15pF VS = 15V TA = 25C 16 12 0V 8 4 100k 10M 1M FREQUENCY (Hz) 00317-023 10k 00317-026 -50mV 0 1k Figure 26. Small-Signal Transient Response Figure 23. Maximum Output Swing vs. Frequency 18 16 POSITIVE SWING 2V 2s 12 10 +5V NEGATIVE SWING 8 AVCL = +1 VS = 15V TA = 25C 6 0V 4 2 TA = 25C VS = 15V -2 100 1k LOAD RESISTANCE () -5V 10k Figure 24. Maximum Output Voltage vs. Load Resistance 00317-027 0 00317-024 MAXIMUM OUTPUT (V) 14 Figure 27. Large Signal Transient Response Rev. F | Page 11 of 20 00317-025 OPEN-LOOP GAIN (V/V) 2.0 VS = 15V VIN = 100mV AV = +1 OP27 TA = 25C VS = 15V 50 0.1F 100k 40 ISC (+) OP27 10 D.U.T. 30 ISC (-) 2k VOLTAGE GAIN = 50,000 20 OP12 1 2 3 5 4 TIME FROM OUTPUT SHORTED TO GROUND (Min) 0.1F 2.2F 24.3k 00317-028 0 Figure 28. Short-Circuit Current vs. Time 110k Figure 31. Voltage Noise Test Circuit (0.1 Hz to 10 Hz) 2.4 140 VS = 15V TA = 25C VCM = 10V TA = 25C VS = 15V OPEN-LOOP VOLTAGE GAIN (V/V) 2.2 120 CMRR (dB) SCOPE x 1 RIN = 1M 100k 4.7F 10 4.3k 22F 00317-031 SHORT-CIRCUIT CURRENT (mA) 60 100 80 2.0 1.8 1.6 1.4 1.2 1.0 0.8 1k 10k 1M 100k FREQUENCY (Hz) 0.4 100 00317-029 60 100 1k 10k LOAD RESISTANCE () 100k 00317-032 0.6 Figure 32. Open-Loop Voltage Gain vs. Load Resistance Figure 29. CMRR vs. Frequency 16 TA = -55C 1 SEC/DIV TA = +25C 120 8 VOLTAGE NOISE (nV) TA = +125C 4 0 TA = -55C -4 TA = +25C -8 TA = +125C -12 80 40 0 -40 -90 -120 0 5 10 15 20 SUPPLY VOLTAGE (V) 0.1Hz TO 10Hz p-p NOISE Figure 33. Low Frequency Noise Figure 30. Common-Mode Input Range vs. Supply Voltage Rev. F | Page 12 of 20 00317-033 -16 00317-030 COMMON-MODE RANGE (V) 12 OP27 160 120 100 NEGATIVE SWING 80 60 POSITIVE SWING 40 20 0 1 10 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 00317-034 POWER SUPPLY REJECTION RATIO (dB) TA = 25C 140 Figure 34. PSRR vs. Frequency Rev. F | Page 13 of 20 OP27 APPLICATION INFORMATION OP27 series units can be inserted directly into OP07 sockets with or without removal of external compensation or nulling components. Additionally, the OP27 can be fitted to unnulled AD741-type sockets; however, if conventional AD741 nulling circuitry is in use, it should be modified or removed to ensure correct OP27 operation. OP27 offset voltage can be nulled to 0 (or another desired setting) using a potentiometer (see Figure 35). The OP27 provides stable operation with load capacitances of up to 2000 pF and 10 V swings; larger capacitances should be decoupled with a 50 resistor inside the feedback loop. The OP27 is unity-gain stable. Thermoelectric voltages generated by dissimilar metals at the input terminal contacts can degrade the drift performance. Best operation is obtained when both input contacts are maintained at the same temperature. To measure the 80 nV p-p noise specification of the OP27 in the 0.1 Hz to 10 Hz range, the following precautions must be observed: * The device must be warmed up for at least five minutes. As shown in the warm-up drift curve, the offset voltage typically changes 4 V due to increasing chip temperature after power-up. In the 10-second measurement interval, these temperature-induced effects can exceed tens-ofnanovolts. * 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 10 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 10 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 correlates well with a 0.1 Hz to 10 Hz p-p noise reading, since both results are determined by the white noise and the location of the 1/f corner frequency. V+ 1 2 OP27 + 3 7 6 OUTPUT 4 00317-035 -- 8 V- Figure 35. Offset Nulling Circuit OFFSET VOLTAGE ADJUSTMENT The input offset voltage of the OP27 is trimmed at wafer level. However, if further adjustment of VOS is necessary, a 10 k trim potentiometer can be used. TCVOS is not degraded (see Figure 35). Other potentiometer values from 1 k to 1 M can be used with a slight degradation (0.1 V/C to 0.2 V/C) of TCVOS. Trimming to a value other than zero creates a drift of approximately (VOS/300) V/C. For example, the change in TCVOS is 0.33 V/C if VOS is adjusted to 100 V. The offset voltage adjustment range with a 10 k potentiometer is 4 mV. If smaller adjustment range is required, the nulling sensitivity can be reduced by using a smaller potentiometer in conjunction with fixed resistors. For example, Figure 36 shows a network that has a 280 V adjustment range. 4.7k 1k POT T 4.7k 8 V+ Figure 36. Offset Voltage Adjustment 00317-036 1 UNITY-GAIN BUFFER APPLICATIONS When Rf 100 and the input is driven with a fast, large signal pulse (>1 V), the output waveform looks as shown in the pulsed operation diagram (see Figure 37). During the fast feedthrough-like portion of the output, the input protection diodes effectively short the output to the input, and a current, limited only by the output short-circuit protection, is drawn by the signal generator. With Rf 500 , the output is capable of handling the current requirements (IL 20 mA at 10 V); the amplifier stays in its active mode and a smooth transition occurs. When Rf > 2 k, a pole is created with Rf and the amplifier's input capacitance (8 pF) that creates additional phase shift and reduces phase margin. A small capacitor (20 pF to 50 pF) in parallel with Rf eliminates this problem. Rf - OP27 + Figure 37. Pulsed Operation Rev. F | Page 14 of 20 2.8V/s 00317-037 10k RP NOISE MEASUREMENTS OP27 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 noise advantage of the OP27 disappears when high source resistors are used. Figure 38, Figure 39, Figure 40 compare the observed total noise of the OP27 with the noise performance of other devices in different circuit applications. (Voltage Noise)2 + 2 Total Noise = (Current Noise x RS ) + 2 (Resistor Noise) 1k OP08/108 500 5534 OP07 1 2 100 OP27/37 1 RS e.g. RS 2 RS e.g. RS 50 UNMATCHED = R S1 = 10k, R S2 = 0 MATCHED = 10k, R S1 = R S2 = 5k RS1 RS2 REGISTER NOISE ONLY 10 50 1/ 2 10k 500 1k 5k RS--SOURCE RESISTANCE () 100 50k 00317-039 The OP27 is a very low noise, monolithic op amp. The outstanding input voltage noise characteristics of the OP27 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 OP27A/E has IB and IOS of only 40 nA and 35 nA at 25C respectively. 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, VOS, and TCVOS of previous designs have made direct coupling difficult, if not impossible, to use. Figure 39 shows the 0.1 Hz to 10 Hz p-p noise. Here the picture is less favorable; resistor noise is negligible and current noise becomes important because it is inversely proportional to the square root of frequency. The crossover with the OP07 occurs in the 3 k to 5 k range depending on whether balanced or unbalanced source resistors are used (at 3 k the IB and IOS error also can be 3x the VOS spec). p-p NOISE (nV) COMMENTS ON NOISE Figure 39. Peak-to-Peak Noise (0.1 Hz to 10 Hz) as Source Resistance (Includes Resistor Noise) Figure 38 shows noise vs. source resistance at 1000 Hz. The same plot applies to wideband noise. To use this plot, multiply the vertical scale by the square root of the bandwidth. For low frequency applications, the OP07 is better than the OP27/OP37 when RS > 3 k. The only exception is when gain error is important. Figure 40 illustrates the 10 Hz noise. As expected, the results are between the previous two figures. 100 50 100 50 OP08/108 1 2 2 TOTAL NOISE (nV/Hz) OP07 10 1 RS e.g. RS 2 RS e.g. RS 5534 OP27/37 1 50 REGISTER NOISE ONLY 100 UNMATCHED = R S1 = 10k, R S2 = 0 MATCHED = 10k, R S1 = R S2 = 5k RS1 RS2 500 1k 5k 10k RS--SOURCE RESISTANCE () 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 50k 1 50 Figure 38. Noise vs. Source Resistance (Including Resistor Noise) at 1000 Hz At RS < 1 k, the low voltage noise of the OP27 is maintained. With RS < 1 k, total noise increases but is dominated by the resistor noise rather than current or voltage noise. lt is only beyond RS of 20 k 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 OP27 and OP07 noise occurs in the 15 k to 40 k region. REGISTER NOISE ONLY 100 RS2 500 1k 5k 10k RS--SOURCE RESISTANCE () 50k 00317-040 5 00317-038 TOTAL NOISE (nV/Hz) 1 Figure 40. 10 Hz Noise vs. Source Resistance (Includes Resistor Noise) Audio Applications Rev. F | Page 15 of 20 OP27 C4 (2) 220F + For reference, typical source resistances of some signal sources are listed in Table 7. MOVING MAGNET CARTRIDGE INPUT Device Strain Gauge Magnetic Tape Head Source Impedance <500 <1500 Magnetic Phonograph Cartridges <1500 Linear Variable Differential Transformer <1500 Comments Typically used in low frequency applications. Low is very important to reduce self-magnetization problems when direct coupling is used. OP27 IB can be neglected. Similar need for low IB in direct coupled applications. OP27 does not introduce any selfmagnetization problems. Used in rugged servo-feedback applications. Bandwidth of interest is 400 Hz to 5 kHz. Table 8. Open-Loop Gain Frequency @ 3 Hz @ 10 Hz @ 30 Hz OP07 100 dB 100 dB 90 dB OP27 124 dB 120 dB 110 dB OP37 125 dB 125 dB 124 dB RA 47.5k 3 CA 150pF A1 OP27 C3 0.47F LF ROLLOFF OUT R5 100k IN 6 R4 75k 2 R1 97.6k R2 7.87k OUTPUT C1 0.03F C2 0.01F R3 100 G = 1kHz GAIN R1 = 0.101 ( 1 + ) R3 = 98.677 (39.9dB) AS SHOWN 00317-041 Table 7. + Figure 41. Phono Preamplifier Circuit The OP27 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 , generating a voltage noise of 1.3 nV/Hz. The noise increases the 3.2 nV/Hz of the amplifier by only 0.7 dB. With a 1 k source, the circuit noise measures 63 dB below a 1 mV reference level, unweighted, in a 20 kHz noise bandwidth. Gain (G) of the circuit at 1 kHz can be calculated by the expression: AUDIO APPLICATIONS Figure 41 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 frequency dependent feedback around a high quality gain block. Properly chosen, an RC network can provide the three necessary time constants of 3180 s, 318 s, and 75 s. For initial equalization accuracy and stability, precision metal film resistors and film capacitors of polystyrene or polypropylene are recommended because they have low voltage coefficients, dissipation factors, and dielectric absorption. (high-k ceramic capacitors should be avoided here, though low-k ceramics, such as NPO types that have excellent dissipation factors and somewhat lower dielectric absorption, can be considered for small values.) R1 G = 0.101 1 + R3 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 show more equalization errors because of the 8 MHz gain bandwidth of the OP27. 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 produces less than 0.03% total harmonic distortion at frequencies up to 20 kHz. 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 roll-off. Placing the rumble filter's high-pass action after the preamplifier 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 preamplifier, though more gain is typically demanded, along with equalization requiring a heavy low frequency boost. The circuit in Figure 41 can be readily modified for tape use, as shown by Figure 42. Rev. F | Page 16 of 20 OP27 OP27 - 15k R1 33k R2 5k 10 0.01F T1 = 3180s T2 = 50s R1 1k Figure 42. Tape Head Preamplifier While the tape equalization requirement has a flat high frequency gain above 3 kHz (T2 = 50 s), 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 can require trimming of R1 and R2 to optimize frequency response for nonideal tape head performance and other factors (see the References section). 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 worstcase output offset is just over 500 mV. A single 0.47 F output capacitor can block this level without affecting the dynamic range. OP27/ OP37 RP 30k R7 10k OUTPUT + R2 1k R3 = R4 R1 R2 R4 316k Figure 43. Fixed Gain Transformerless Microphone Preamplifier For applications demanding appreciably lower noise, a high quality microphone transformer coupled preamplifier (Figure 44) incorporates the internally compensated OP27. T1 is a JE115K-E 150 /15 k transformer that 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. C2 1800pF R1 121 Amplifier bias-current transients that can magnetize a head present one potential tape head problem. The OP27 and OP37 are free of bias current transients upon power-up or powerdown. It is always advantageous to control the speed of power supply rise and fall to eliminate transients. A simple, but effective, fixed gain transformerless microphone preamp (Figure 43) amplifies differential signals from low impedance microphones by 50 dB and has an input impedance of 2 k. Because of the high working gain of the circuit, an OP37 helps to preserve bandwidth, which is 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 can cause the amplifier to oscillate. R6 100 - LOW IMPEDANCE MICROPHONE INPUT (Z = 50 TO 200) The tape head can be coupled directly to the amplifier input, because the worst-case bias current of 80 nA with a 400 mH, 100 inch head (such as the PRB2H7K) is not troublesome. In addition, the dc resistance of the head should be carefully controlled and preferably below 1 k. For this configuration, the bias current induced offset voltage can be greater than the 100 pV maximum offset if the head resistance is not sufficiently controlled. C1 5mF R3 316k 00317-043 CA R2 1100 2 T11 A1 OP27 6 OUTPUT 3 150 SOURCE R3 100 1 T1 - JENSEN JE - 115K - E JENSEN TRANSFORMERS 00317-044 RA 00317-042 TAPE HEAD 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 is about 6 nV/Hz, equivalent to 0.9 V in a 20 kHz noise bandwidth, or nearly 61 dB below a 1 mV input signal. Measurements confirm this predicted performance. 0.47F Figure 44. High Quality Microphone Transformer Coupled Preamplifier Gain can 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 is very low, 1.7 mV or less, for a 40 dB gain. The typical output blocking capacitor can be eliminated in such cases, but it is desirable for higher gains to eliminate switching transients. 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. Rev. F | Page 17 of 20 +18V 8 2 OP27 3 7 6 4 -18V Figure 45. Burn-In Circuit 00317-045 + OP27 Capacitor C2 and Resistor R2 form a 2 s time constant in this circuit, as recommended for optimum transient response by the transformer manufacturer. With C2 in use, A1 must have unitygain stability. For situations where the 2 s time constant is not necessary, C2 can be deleted, allowing the faster OP37 to be employed. A 150 resistor and R1 and R2 gain resistors connected to a noiseless amplifier 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 is close to 3.6 dB (or -69.5 referenced to 1 mV). REFERENCES 1. Lipshitz, S. R, "On RIAA Equalization Networks," JAES, Vol. 27, June 1979, p. 458-481. 2. Jung, W. G., IC Op Amp Cookbook, 2nd. Ed., H. W. Sams and Company, 1980. 3. Jung, W. G., Audio IC Op Amp Applications, 2nd. Ed., H. W. Sams and Company, 1978. 4. Jung, W. G., and Marsh, R. M., "Picking Capacitors," Audio, February and March, 1980. 5. Otala, M., "Feedback-Generated Phase Nonlinearity in Audio Amplifiers," London AES Convention, March 1980, preprint 1976. 6. Stout, D. F., and Kaufman, M., Handbook of Operational Amplifier Circuit Design, New York, McGraw-Hill, 1976. Rev. F | Page 18 of 20 OP27 OUTLINE DIMENSIONS 0.400 (10.16) 0.365 (9.27) 0.355 (9.02) 8 5 1 4 0.280 (7.11) 0.250 (6.35) 0.240 (6.10) 0.100 (2.54) BSC 0.060 (1.52) MAX 0.210 (5.33) MAX 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.195 (4.95) 0.130 (3.30) 0.115 (2.92) 0.015 (0.38) MIN 0.015 (0.38) GAUGE PLANE SEATING PLANE 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 5.00 (0.1968) 4.80 (0.1890) 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) PIN 1 0.430 (10.92) MAX 0.005 (0.13) MIN 8 4.00 (0.1574) 3.80 (0.1497) 1 0.014 (0.36) 0.010 (0.25) 0.008 (0.20) 5 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) 6.20 (0.2440) 5.80 (0.2284) 8 0.25 (0.0098) 0 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067) 0.51 (0.0201) COPLANARITY SEATING 0.31 (0.0122) 0.10 PLANE 0.070 (1.78) 0.060 (1.52) 0.045 (1.14) 0.50 (0.0196) x 45 0.25 (0.0099) 1.75 (0.0688) 1.35 (0.0532) COMPLIANT TO JEDEC STANDARDS MS-001-BA 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. CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS. COMPLIANT TO JEDEC STANDARDS MS-012-AA 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. Figure 46. 8-Lead Plastic Dual-in-Line Package [PDIP] (N-8) P-Suffix Dimensions shown in inches and (millimeters) Figure 48. 8-Lead Standard Small Outline Package [SOIC] Narrow Body (R-8) S-Suffix Dimensions shown in millimeters and (inches) 0.005 (0.13) MIN 5 REFERENCE PLANE 0.310 (7.87) 0.220 (5.59) 1 4 0.1850 (4.70) 0.1650 (4.19) 0.0500 (1.27) MAX 0.100 (2.54) BSC 0.150 (3.81) MIN 0.200 (5.08) 0.125 (3.18) 0.023 (0.58) 0.014 (0.36) 0.070 (1.78) 0.030 (0.76) SEATING PLANE 15 0 0.015 (0.38) 0.008 (0.20) 0.3700 (9.40) 0.3350 (8.51) 0.060 (1.52) 0.015 (0.38) 0.1000 (2.54) BSC 0.1600 (4.06) 0.1400 (3.56) 5 0.3350 (8.51) 0.3050 (7.75) 0.320 (8.13) 0.290 (7.37) 0.405 (10.29) MAX 0.200 (5.08) MAX 0.5000 (12.70) MIN 0.2500 (6.35) MIN 0.2000 (5.08) BSC 0.0400 (1.02) MAX 0.0400 (1.02) 0.0100 (0.25) 0.0190 (0.48) 0.0160 (0.41) 0.1000 (2.54) BSC 0.0210 (0.53) 0.0160 (0.41) 4 6 2 8 3 7 1 0.0450 (1.14) 0.0270 (0.69) 0.0340 (0.86) 0.0280 (0.71) 45 BSC BASE & SEATING PLANE COMPLIANT TO JEDEC STANDARDS MO-002-AK 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. 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. Figure 47. 8-Lead Ceramic DIP - Glass Hermetic Seal [CERDIP] (Q-8) Z-Suffix Dimensions shown in inches and (millimeters) Figure 49. 8-Lead Metal Can [TO-99] (H-08) J-Suffix Dimensions shown in inches and (millimeters) Rev. F | Page 19 of 20 022306-A 8 0.055 (1.40) MAX OP27 ORDERING GUIDE Model OP27AJ/883C OP27GJ OP27AZ OP27AZ/883C OP27EZ OP27GZ OP27EP OP27EPZ 1 OP27GP OP27GPZ1 OP27GS OP27GS-REEL OP27GS-REEL7 OP27GSZ1 OP27GSZ-REEL1 OP27GSZ-REEL71 OP27NBC 1 Temperature Range -55 to +125C -40 to +85C -55 to +125C -55 to +125C -25 to +85C -40 to +85C 0 to +70C 0 to +70C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C -40 to +85C Package Description 8-Lead Metal Can (TO-99) 8-Lead Metal Can (TO-99) 8-Lead CERDIP 8-Lead CERDIP 8-Lead CERDIP 8-Lead CERDIP 8-Lead PDIP 8-Lead PDIP 8-Lead PDIP 8-Lead PDIP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC Die Z = Pb-free part. (c)2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C00317-0-5/06(F) Rev. F | Page 20 of 20 Package Option J-Suffix (H-08) J-Suffix (H-08) Z-Suffix (Q-8) Z-Suffix (Q-8) Z-Suffix (Q-8) Z-Suffix (Q-8) P-Suffix (N-8) P-Suffix (N-8) P-Suffix (N-8) P-Suffix (N-8) S-Suffix (R-8) S-Suffix (R-8) S-Suffix (R-8) S-Suffix (R-8) S-Suffix (R-8) S-Suffix (R-8)