OP27

Low Noise, Precision Operational Amplifier OP27 FEATURES Low noise: 80 nV p-p (0.1 Hz to 10 Hz), 3 nV/√Hz Low drift: 0.2 μV/°C High speed: 2.8 V/μs slew rate, 8 MHz gain bandwidth Low VOS: 10 μV Excellent CMRR: 126 dB at VCM of ±11 V High open-loop gain: 1.8 million Fits OP07, 5534A sockets Available in die form PIN CONFIGURATIONS BAL BAL 1 –IN 2 +IN 3 V+ OUT NC 00317-001 OP27 4V– (CASE) NC = NO CONNECT Figure 1. 8-Lead TO-99 (J-Suffix) GENERAL DESCRIPTION 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 μV and maximum drift of 0.6 μV/°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/μs slew rate provide excellent dynamic accuracy in high speed, dataacquisition systems. 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 Ω and low output distortion make the OP27 an excellent choice for professional audio applications. (Continued on Page 3) VOS TRIM 1 –IN 2 +IN 3 V– 4 OP27 8 VOS TRIM 7 V+ 6 OUT 00317-002 5 NC NC = NO CONNECT Figure 2. 8-Lead CERDIP – Glass Hermetic Seal (Z-Suffix), 8-Lead PDIP (P-Suffix), 8-Lead SO (S-Suffix) FUNCTIONAL BLOCK DIAGRAM V+ R3 Q6 R11 1 8 R4 R21 C2 Q22 Q21 R23 Q23 R24 Q24 R9 Q20 Q1A NONINVERTING INPUT (+) Q3 INVERTING INPUT (–) 1 R1 . VOS ADJ. C1 Q46 Q19 OUTPUT Q1B Q2B Q2A R5 C3 R12 C4 Q11 Q12 Q27 Q28 Q26 Q45 V– 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 ©2006 Analog Devices, Inc. All rights reserved. 00317-003 AND R2 ARE PERMANENTLY ADJUSTED AT WAFER TEST FOR MINIMUM OFFSET VOLTAGE OP27 TABLE OF CONTENTS Features .............................................................................................. 1 General Description ......................................................................... 1 Pin Configurations ........................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications..................................................................................... 4 Electrical Characteristics............................................................. 4 Typical Electrical Characteristics ............................................... 6 Absolute Maximum Ratings............................................................ 7 Thermal Resistance ...................................................................... 7 ESD Caution.................................................................................. 7 Typical Performance Characteristics ..............................................8 Application Information................................................................ 14 Offset Voltage Adjustment ........................................................ 14 Noise Measurements.................................................................. 14 Unity-Gain Buffer Applications ............................................... 14 Comments On Noise ................................................................. 15 Audio Applications .................................................................... 16 References.................................................................................... 18 Outline Dimensions ....................................................................... 19 Ordering Guide............................................................................... 20 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 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 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 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 μV/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 = 25°C, 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 INPUT NOISE Current Density3 INPUT RESISTANCE Differential Mode 5 Common Mode INPUT VOLTAGE RANGE COMMON-MODE REJECTION RATIO POWER SUPPLY REJECTION RATIO LARGE SIGNAL VOLTAGE GAIN OUTPUT VOLTAGE SWING SLEW RATE 6 GAIN BANDWIDTH PRODUCT6 OPEN-LOOP OUTPUT RESISTANCE POWER CONSUMPTION OFFSET ADJUSTMENT RANGE 1 2 Symbol VOS VOS/Time IOS IB en p-p en Conditions Min in 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 ±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 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 Unit μV μV/MO nA nA μV p-p nV/√Hz nV/√Hz nV/√Hz pA/√Hz pA/√Hz pA/√Hz MΩ GΩ V dB μV/V V/mV V/mV V V V/μs MHz Ω mW mV RIN RINCM IVR CMRR PSRR AVO VO SR GBW RO Pd 0.7 ±11.0 100 10 700 600 ±11.5 ±10.0 1.7 5.0 140 VCM = ±11 V VS = ±4 V to ±18 V RL ≥ 2 k Ω, VO = ±10 V RL ≥ 600 Ω, VO = ±10 V RL ≥ 2 k Ω RL ≥ 600 Ω RL ≥ 2 kΩ VO = 0, IO = 0 VO RP = 10 kΩ 20 170 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 μV. 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. Rev. F | Page 4 of 20 OP27 VS = ±15 V, −55°C ≤ TA ≤ 125°C, unless otherwise noted. Table 2. Parameter INPUT OFFSET VOLTAGE 1 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 Symbol VOS TCVOS 2 TCVOSn 3 IOS IB IVR CMRR PSRR AVO VO Conditions Min OP27A Typ 30 0.2 15 ±20 ±11.5 122 2 1200 ±13.5 Max 60 0.6 50 ±60 Unit μV μV/°C nA nA V dB μV/V V/mV V VCM = ±10 V VS = ±4.5 V to ±18 V RL ≥ 2 kΩ, VO = ±10 V RL ≥ 2 kΩ ±10.3 108 600 ±11.5 16 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 kΩ to 20 kΩ. TCVOS is 100% tested for A/E grades, sample tested for G grades. 3 Guaranteed by design. VS = ±15 V, −25°C ≤ TA ≤ 85°C for OP27J, OP27Z, 0°C ≤ TA ≤ 70°C for OP27EP, and –40°C ≤ TA ≤ 85°C 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 Min VCM = ±10 V VS = ±4.5 V to ±18 V RL ≥ 2 kΩ, VO = ±10 V RL ≥ 2 kΩ ±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 μV μV/°C μV/°C nA nA V dB μV/V V/mV V The TCVOS performance is within the specifications unnulled or when nulled with RP = 8 kΩ to 20 kΩ. 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 = 25°C 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 Symbol TCVOS or TCVOSn TCIOS TCIB en en en in in in enp-p SR GBW Conditions Nulled or unnulled RP = 8 kΩ to 20 kΩ OP27N Typical 0.2 80 100 3.5 3.1 3.0 1.7 1.0 0.4 0.08 2.8 8 Unit μV/°C pA/°C pA/°C nV/√Hz nV/√Hz nV/√Hz pA/√Hz pA/√Hz pA/√Hz μV p-p V/μs MHz fO = 10 Hz fO = 30 Hz fO = 1000 Hz fO = 10 Hz fO = 30 Hz fO = 1000 Hz 0.1 Hz to 10 Hz RL ≥ 2 kΩ INPUT NOISE CURRENT DENSITY INPUT NOISE VOLTAGE SLEW RATE GAIN BANDWIDTH PRODUCT 1 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 1 Rating ±22 V ±22 V Indefinite ±0.7 V ±25 mA −65°C to +150°C −55°C to +125°C −25°C to +85°C 0°C to 70°C −40°C to +85°C 300°C −65°C to +150°C 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 θJA is specified for the worst-case conditions, that is, θJA is specified for device in socket for TO, CERDIP, and PDIP packages; θJA 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. Table 6. Package Type TO-99 (J) 8-Lead Hermetic DlP (Z) 8-Lead Plastic DIP (P) 8-Lead SO (S) θJA 150 148 103 158 θJC 18 16 43 43 Unit °C/W °C/W °C/W °C/W 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. 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 OP27 TYPICAL PERFORMANCE CHARACTERISTICS 100 90 80 RMS VOLTAGE NOISE (μV) 10 TA = 25°C VS = ±15V 1 GAIN (dB) 70 60 50 40 30 0.01 TEST TIME OF 10sec FURTHER LIMITS LOW FREQUENCY (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 Ω, 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 kΩ, 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 V+ Figure 36. Offset Voltage Adjustment – OP27 + 2.8V/μs 00317-037 Figure 37. Pulsed Operation Rev. F | Page 14 of 20 OP27 COMMENTS ON NOISE 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 25°C 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. 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. 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 kΩ to 5 kΩ range depending on whether balanced or unbalanced source resistors are used (at 3 kΩ the IB and IOS error also can be 3× the VOS spec). 1k OP08/108 500 5534 OP07 p-p NOISE (nV) 1 100 OP27/37 50 2 1 RS e.g. RS 2 RS e.g. RS UNMATCHED = R S1 = 10kΩ, R S2 = 0 MATCHED = 10kΩ, R S1 = R S2 = 5kΩ RS1 REGISTER NOISE ONLY 10 50 100 RS2 ⎡(Voltage Noise)2 + ⎤ ⎢ ⎥ 2 Total Noise = ⎢(Current Noise × RS ) + ⎥ ⎢ ⎥ 2 ⎢(Resistor Noise) ⎥ ⎣ ⎦ 1/ 2 10k 500 1k 5k RS—SOURCE RESISTANCE (Ω) 50k 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. 100 For low frequency applications, the OP07 is better than the OP27/OP37 when RS > 3 kΩ. 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 1 TOTAL NOISE (nV/√Hz) OP08/108 2 10 1 RS e.g. RS 2 RS e.g. RS UNMATCHED = R S1 = 10kΩ, R S2 = 0 MATCHED = 10kΩ, R S1 = R S2 = 5kΩ RS1 50 1 2 OP08/108 TOTAL NOISE (nV/√Hz) OP07 5 5534 OP27/37 REGISTER NOISE ONLY 100 10 OP07 5534 5 OP27/37 RS2 1 RS e.g. RS 2 RS e.g. RS UNMATCHED = R S1 = 10kΩ, R S2 = 0 MATCHED = 10kΩ, R S1 = R S2 = 5kΩ RS1 500 1k 5k 10k RS—SOURCE RESISTANCE (Ω) 50k 00317-038 1 50 Figure 38. Noise vs. Source Resistance (Including Resistor Noise) at 1000 Hz 100 500 1k 5k 10k RS—SOURCE RESISTANCE (Ω) 50k At RS < 1 kΩ, the low voltage noise of the OP27 is maintained. With RS < 1 kΩ, total noise increases but is dominated by the resistor noise rather than current or voltage noise. lt is only beyond RS of 20 kΩ 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 kΩ to 40 kΩ region. Figure 40. 10 Hz Noise vs. Source Resistance (Includes Resistor Noise) Audio Applications Rev. F | Page 15 of 20 00317-040 1 50 REGISTER NOISE ONLY RS2 00317-039 OP27 For reference, typical source resistances of some signal sources are listed in Table 7. Table 7. Device Strain Gauge Magnetic Tape Head Source Impedance