Low-Noise, Precision Operational Amplifier OP27 PIN CONNECTIONS
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 725, 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
GENERAL DESCRIPTION
Figure 1. TO-99 (J-Suffix) VOS TRIM 1
OP27
8
VOS TRIM
–IN 2
7 VOS TRIM
+IN 3
6 OUT
V– 4
5 NC
NC = NO CONNECT
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 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 provides excellent dynamic accuracy in high speed, dataacquisition systems.
Figure 2. 8-Lead Hermetic DIP (Z-Suffix) 8-Lead Plastic DIP (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 Ω and low output distortion make the OP27 an excellent choice for professional audio applications. (Continued on Page 3)
SIMPLIFIED SCHEMATIC V+ R3 Q6 R1*
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. D 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 © 2005 Analog Devices, Inc. All rights reserved.
OP27 TABLE OF CONTENTS Features .............................................................................................. 1
Typical Performance Characteristics ..............................................8
General Description ......................................................................... 1
Application Information................................................................ 14
Pin Connections ............................................................................... 1
Offset Voltage Adjustment ........................................................ 14
Simplified Schematic........................................................................ 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
ESD Caution.................................................................................. 7
Ordering Guide............................................................................... 20
REVISION HISTORY 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. D | 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 proved 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 725, OP06, OP07, and OP45 amplifiers; 741 types may be directly replaced by removing the 741’s nulling potentiometer.
Rev. D | 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
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 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
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
12
0.7 ±11.0 100 10 700 600 ±11.5 ±10.0 1.7 5.0 140
OP27/G Typ 30 0.4 75 ±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 nA ±80 0.25 8.0 5.6 4.5
0.6
20
170
Unit μV μV/MO nA μV p-p nV/√Hz nV/√Hz nV/√Hz pA/√Hz pA/√Hz pA/√Hz MΩ GΩ V dB μV/V V/μV V/μV V V V/μs MHz Ω mW mV
Input offset voltage measurements are performed ~ 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 Typical Performance Characteristics. 3 Sample tested. 4 See voltage noise test circuit (Figure 31). 5 Guaranteed by input bias current. 6 Guaranteed by design. 2
Rev. D | 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
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 kΩ, VO = ±10 V RL ≥ 2 kΩ
Min
OP27A Typ 30
±10.3 108
0.2 15 ±20 ±11.5 122 2 1200 ±13.5
600 ±11.5
Max 60
Unit μV
0.6 50 ±60
μV/°C nA nA V dB μV/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 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
VCM = ±10 V VS = ±4.5 V to ±18 V RL ≥ 2 kΩ, VO = ±10 V RL ≥ 2 kΩ
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 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. D | 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
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 kΩ to 20 kΩ
in in in enp-p SR GBW
fO = 10 Hz fO = 30 Hz fO = 1000 Hz 0.1 Hz to 10 Hz RL ≥ 2 kΩ
fO = 10 Hz fO = 30 Hz fO = 1000 Hz
OP27N Typical 0.2
Unit μV/°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 μV p-p V/μs MHz
Input offset voltage measurements are performed by automated test equipment approximately 0.5 sec after application of power.
Rev. D | 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
For supply voltages less than ±22 V, the absolute maximum input voltage is equal to the supply voltage. 2 The OP27’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.
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. 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) 1
θJA 1 150 148 103 158
θJC 18 16 43 43
Unit °C/W °C/W °C/W °C/W
θJA is specified for worst-case mounting conditions, that is, θJA is specified for device in socket for TO, CERDIP, and P-DIP packages; θJA is specified for device soldered to printed circuit board for SO package.
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. D | Page 7 of 20
OP27 TYPICAL PERFORMANCE CHARACTERISTICS 100
10 TA = 25°C VS = ±15V RMS VOLTAGE NOISE (μV)
90
70
60 50
1
0.1
TEST TIME OF 10sec FURTHER LIMITS LOW FREQUENCY (1 V), the output waveform will look as shown in the pulsed operation diagram (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, will be 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 will stay in its active mode and a smooth transition will occur. When Rf > 2 kΩ, a pole will be 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 will eliminate this problem. Rf
–
OP27 +
Figure 37. Pulsed Operation Rev. D | Page 14 of 20
2.8V/μs 00317-037
10kΩ RP
NOISE MEASUREMENTS
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. B
Figure 39 shows the 0.1 Hz to 10 Hz peak-to-peak 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.). B
1k OP08/108 500
5534
B
p-p NOISE (nV)
OP07
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 OP27’s noise advantage disappears when high source-resistors are used. Figure 38, Figure 39, Figure 40 compare OP27’s observed total noise with the noise performance of other devices in different circuit applications.
OP27/37
100
10k 500 1k 5k RS—SOURCE RESISTANCE (Ω)
50k
Therefore, 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. For reference, typical source resistances of some signal sources are listed in Table 7.
1
Table 7.
OP08/108 2 OP07
Device Strain Gauge
10
OP27/37 REGISTER NOISE ONLY
UNMATCHED = R S1 = 10kΩ, R S2 = 0 MATCHED = 10kΩ, R S1 = R S2 = 5kΩ RS1
Source Impedance
