Analog Devices OP37EP, OP37EZ, OP37FP, OP37GP, OP37GZ Datasheet

Low Noise, Precision, High Speed

8

7

6

5

1

2

3

4

NC = NO CONNECT

V

OS

TRIM

–IN

+IN

V

OS

TRIM

V+

OUT

NCV–

OP37

a

FEATURES
Low Noise, 80 nV p-p (0.1 Hz to 10 Hz)

3 nV/√Hz @ 1 kHz

Low Drift, 0.2 ␮V/ⴗC
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

GENERAL DESCRIPTION

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/µs and
gain-bandwidth product to 63 MHz.

The OP37 provides the low offset and drift of the OP07
plus higher speed and lower noise. Offsets down to 25 µV and
drift

of 0.6 µV/°C maximum make the OP37 ideal for preci-

sion

instrumentation applications. Exceptionally low noise

=

3.5 nV/ @ 10 Hz), a low 1/f noise corner frequency of

(e

n

2.7 Hz,
high-gain amplification of low-level signals.

The low input bias current of 10 nA and offset current of 7 nA
are achieved by using a bias-current cancellation circuit.
the military temperature range this typically holds I
to 20 nA and 15 nA respectively.

and the high gain of 1.8 million, allow accurate

Over

and I

B

OS

Operational Amplifier (A

VCL

> 5)

OP37

The output stage has good load driving capability. A guaranteed
swing of 10 V into 600 Ω and low output distortion make the
OP37 an excellent choice for professional audio applications.

PSRR and CMRR exceed 120 dB. These characteristics, coupled
with long-term drift of 0.2 µV/month, allow the circuit
to achieve performance levels previously attained only by
discrete designs.

Low-cost, high-volume production of the OP37 is achieved
using on-chip zener-zap trimming. This reliable and stable
trimming scheme has proved its effectiveness over many
production history.

The OP37 brings low-noise instrumentation-type performance
such diverse applications as microphone, tapehead, and RIAA
phono preamplifiers, high-speed signal conditioning for data
acquisition systems, and wide-bandwidth instrumentation.

PIN CONNECTIONS

8-Lead Hermetic DIP

(Z Suffix)

Epoxy Mini-DIP

(P Suffix)

8-Lead SO

(S Suffix)

designer

by

offset

years of

to

SIMPLIFIED SCHEMATIC

V+

C2

Q21

Q23

Q27 Q28

R23 R24

R5

Q24

Q22

C1

R9

R12

C3 C4

Q20 Q19

Q26

Q46

OUTPUT

Q45

V–

NON-INVERTING

INPUT (+)

INVERTING

INPUT (–)

R1 AND R2 ARE PERMANENTLY

*

ADJUSTED AT WAFER TEST FOR
MINIMUM OFFSET VOLTAGE.

Q6

Q3

R1*

R3

18

ADJ.

V

OS

Q2B

R4

R2*

Q2AQ1A Q1B

Q11 Q12

REV. A

Information furnished by Analog Devices is believed to be accurate and

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.

reliable. However, no responsibility is assumed by Analog Devices for its

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © Analog Devices, Inc., 2002

OP37

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS

4

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 . . . . . . . . . . . . . –65°C to +150°C

Operating Temperature Range

OP37A . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +1 25°C

OP37E (Z) . . . . . . . . . . . . . . . . . . . . . . . . . . –25°C to +85°C

OP37E, OP-37F (P) . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C

OP37G (P, S, Z) . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300°C

Junction Temperature . . . . . . . . . . . . . . . . . . –45°C to +150°C

Package Type ␪

3

␪

JA

Unit

JC

8-Lead Hermetic DIP (Z) 148 16 °C/W
8-Lead Plastic DIP (P) 103 43 °C/W
8-Lead SO (S) 158 43 °C/W

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.

ORDERING GUIDE

TA = 25°C Operating

MAX CerDIP Plastic Temperature

V

OS

(µV) 8-Lead 8-Lead Range

25 OP37AZ* MIL
25 OP37EZ OP37EP IND/COM
60 OP37FP* IND/COM
100 OP37GP XIND
100 OP37GZ OP37GS XIND

*Not for new design, obsolete, April 2002.

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–

REV. A

OP37

SPECIFICATIONS

( VS = 15 V, TA = 25C, unless otherwise noted.)

OP37A/E OP37F OP37G

Parameter Symbol Conditions Min Typ Max Min Typ Max Min Typ Max Unit

Input Offset
Voltage V

OS

Note 1 10 25 20 60 30 100 µV

Long-Term
Stability V

/Time Notes 2, 3 0.2 1.0 0.3 1.5 0.4 2.0 µV/Mo

OS

Input Offset
Current I

OS

7 35 9 50 12 75 nA
Input Bias
Current I
Input Noise
Voltage e
Input Noise
Voltage Density e

Input Noise
CurrentDensity i

B

np-p

n

N

1 Hz to 10 Hz

fO = 10 Hz

= 30 Hz

f

O

= 1000 Hz

f

O

fO = 10 Hz
f

= 30 Hz

O

= 1000 Hz

f

O

3

3

3, 6

3, 6

3, 5

3

3, 6

±10 ±40 ±12 ± 55 ±15 ± 80 nA

0.08 0.18 0.08 0.18 0.09 0.25 µV p-p

3.5 5.5 3.5 5.5 3.8 8.0

3.1 4.5 3.1 4.5 3.3 5.6 nV/√ Hz

3.0 3.8 3.0 3.8 3.2 4.5

1.7 4.0 1.7 4.0 1.7

1.0 2.3 1.0 2.3 1.0 pA/√ Hz

0.4 0.6 0.4 0.6 0.4 0.6
Input Resistance
Differential
Mode R

IN

Note 7 1.3 6 0.9 4 5 0.7 4 MΩ

Input Resistance
Common Mode

R

INCM

3 2.5 2 GΩ

Input Voltage
Range IVR ±11 ±12.3 ± 11 ± 12.3 ±11 ±12.3 V
Common Mode
Rejection Ratio

CMRR VCM = ±11 V 114 126 106 123 100 120 dB
Power Supply
Rejection Ratio

PSSR VS = ±4 V 1 10 1 10 2 20 µV/ V

to ±18 V

Large Signal
Voltage Gain A

VO

RL ≥ 2 kΩ,

= ±10 V 1000 1800 1000 1800 700 1500 V/m V

V

O

R

≥ 1 kΩ,

L

Vo = ±10 V 800 1500 800 1500 400 1500 V/m V
R

≥ 600 Ω,

L

= ±1 V,

V

O

4

V

S

±4

250 700 250 700 200 500 V/m V
Output Voltage
Swing V

O

Slew Rate SR R
Gain Bandwidth
Product GBW f

RL ≥ 2 kΩ±12.0 ± 13.8 ±12.0 ± 13.8 ±11.5 ±13.5 V

≥ 600 Ω±10 ±11.5 ±10 ±11.5 ± 10 ±11.5 V

R

L

L

= 10 kHz

O

= 1 MHz 40 40 40 MHz

f

O

≥ 2k Ω

4

11 17 11 17 11 17 V/µs

4

45 63 45 63 45 63 MHz

Open-Loop
Output Resistance

R

O

VO = 0, IO = 0 70 70 70 Ω
Power
Consumption P

d

VO = 0 90 140 90 140 100 170 mW
Offset Adjustment
Range RP = 10 kΩ±4 ±4 ±4mV

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 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 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. A

–3–

OP37–SPECIFICATIONS

Electrical Characteristics

( VS = 15 V, –55C < TA < +125C, unless otherwise noted.)

OP37A OP37C

Parameter Symbol Conditions Min Typ Max Min Typ Max Unit

Input Offset
Voltage V

OS

Note 1 10 25 30 100 µV

Average Input
Offset Drift TCV

TCV

OS

OSN

Note 2
Note 3 0.2 0.6 0.4 1.8 µV/°C

Input Offset
Current I

OS

15 50 30 135 nA
Input Bias
Current I

B

±20 ±60 ±35 ± 150 nA
Input Voltage
Range IVR ±10.3 ±11.5 ±± 10.2 ± 11.5 V
Common Mode
Rejection Ratio CMRR V

= ±10 V 108 122 94 116 dB

CM

Power Supply
Rejection Ratio PSRR V

= ±4.5 V to

S

±18 V 2 16 4 51 µV/ V

Large-Signal
Voltage Gain A

VO

RL ≥ 2 kΩ,
V

= ±10 V 600 1200 300 800 V/m V

O

Output Voltage
Swing V

O

RL ≥ 2 kΩ±11.5 ±13.5 ±10.5 ± 13.0 V

(VS = 15 V, –25C < TA < +85C for OP37EZ/FZ, 0C < TA < 70C for OP37EP/FP, and –40C < T

Electrical Characteristics

< +85C for OP37GP/GS/GZ, unless otherwise noted.)

OP37E OP37F OP37C

Parameter Symbol Conditions Min Typ Max Min Typ Max Min Typ Max Unit

Input Offset
Voltage V

OS

20 50 40 140 55 220 µV

Average Input
Offset Drift TCV

TCV

Note 2

OS

Note 3 0.2 0.6 0.3 1.3 0.4 1.8 µV/°C

OSN

Input Offset
Current I

OS

10 50 14 85 20 135 nA
Input Bias
Current I

B

±14 ±60 ±18 ± 95 ± 25 ± 150 nA
Input Voltage
Range IVR ±10.5 ±11.8 ±10.5 ±11.8 ±10.5 ± 11.8 V
Common Mode
Rejection Ratio CMRR V

= ±10 V 108 122 100 119 94 116 dB

CM

Power Supply
Rejection Ratio PSRR V

= ±4.5 V to

S

±18 V 2 15 2 16 4 32 µV/ V

Large-Signal
Voltage Gain A

VO

RL ≥ 2 kΩ,

= ±10 V 750 1500 700 1300 450 1000 V/mV

VO

Output Voltage
Swing 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

3

Guaranteed by design.

performance is within the specifications unnulled or when nulled withRP = 8 kΩ to 20 kΩ. TC

VOS

O

RL ≥ 2 kΩ±11.7 ± 13.6 ± 11.4 ± 13.5 ±11 ±13.3 V

is 100% tested for A/E grades, sample tested for F/G grades.

VOS

A

–4–

REV. A

OP37

1. NULL

2. (–) INPUT

3. (+) INPUT

4. V–

6. OUTPUT

7. V+

8. NULL

(VS = 15 V, TA = 25C for OP37N, OP37G, and OP37GR devices; TA = 125C for OP37NT and OP37GT devices,

Wafer Test Limits

Parameter Symbol Conditions Limit Limit Limit Limit Limit Unit

Input Offset
Voltage V
Input Offset
Current I
Input Bias
Current I
Input Voltage
Range IVR ±10.3 ± 11 ±10.3 ± 11 ± 11 V MIN
Common Mode
Rejection Ratio CMRR V

OS

OS

B

unless otherwise noted.)

OP37NT OP37N OP37GT OP37G OP37GR

Note 1 60 35 200 60 100 µV MAX

50 35 85 50 75 nA MAX

±60 ±40 ± 95 ±55 ±80 nA MAX

= ±11 V 108 114 100 106 100 dB MIN

CM

Power Supply
Rejection Ratio PSRR T

= 25°C,

A

= ±4 V to

V

S

±18 V1010101020µV/V MAX
T

= 125°C,

A

= ±4.5 V to

V

S

±18 V 16 20 µV/V MAX

Large-Signal
Voltage Gain A

VO

RL ≥ 2 kΩ,
V

= ±10 V 600 1000 500 1000 700 V/mV MIN

O

R

≥ 1 kΩ,

L

= ±10 V 800 800 V/mV MIN

V

O

Output Voltage
Swing V

O

RL ≥ 2 kΩ±11.5 ± 12 ±11 ±12 ±11.5 V MIN

≥ 600 kΩ±10 ± 10 ± 10 V MIN

R

L

Power
Consumption P

NOTES
For 25°C 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.

d

VO = 0 140 140 170 mW MAX

REV. A

–5–

OP37

Typical Electrical Characteristics

(VS = 15 V, TA = 25C, unless otherwise noted.)

OP37NT OP37N OP37GT OP37G OP37GR

Parameter Symbol Conditions Typical Typical Typical Typical Typical Unit

Average Input
Offset Voltage

TCV

OS

OSN

or Nulled or

Unnulled

= 8 kΩ

R

P

Drift TCV

to 20 kΩ 0.2 0.2 0.3 0.3 0.4 µV/°C

Average Input
Offset Current
Drift TCI

OS

80 80 130 130 180 pA/°C

Average Input
Bias Current
Drift TCI

B

100 100 160 160 200 pA/°C

Input Noise
Voltage Density e

n

fO = 10 Hz 3.5 3.5 3.5 3.5 3.8 nV/√Hz

= 30 Hz 3.1 3.1 3.1 3.1 3.3 nV/√Hz

f

O

f

= 1000 Hz 3.0 3.0 3.0 3.0 3.2 nV/√Hz

O

Input Noise
Current Density i

n

fO = 10 Hz 1.7 1.7 1.7 1.7 1.7 pA/√ Hz

= 30 Hz 1.0 1.0 1.0 1.0 1.0 pA/√ Hz

f

O

f

= 1000 Hz 0.4 0.4 0.4 0.4 0.4 pA/√ Hz

O

Input Noise
Voltage e

n p-p

0.1 Hz to
10 Hz 0.08 0.08 0.08 0.08 0.09 µV p-p

Slew Rate SR R

≥ 2k Ω 17 17 17 17 17 V/µs

L

Gain Bandwidth
Product GBW fO = 10 kHz 63 63 63 63 63 MHz

–6–

REV. A

Typical Performance Characteristics–

OP37

100

90

80

70

60

GAIN – dB

50

TEST TIME OF 10sec MUST BE USED
TO LIMIT LOW FREQUENCY

40

(<0.1Hz) GAIN.

30

0.01

0.1 1 10 100
FREQUENCY – Hz

TPC 1. Noise-Tester Frequency
Response (0.1 Hz to 10 Hz)

10

TA = 25C

= 15V

V

S

1

0.1

RMS VOLTAGE NOISE – V

0.01
100 1k 10k

BANDWIDTH – Hz

100k

TPC 4. Input Wideband Voltage Noise

vs. Bandwidth (0.1 Hz to Frequency
Indicated)

10

9
8

7
6

5

4

3

I/F CORNER = 2.7Hz

2

VOLTAGE NOISE – nV/ Hz

1

1

10 100 1k

FREQUENCY – Hz

TA = 25C

= 15V

V

S

TPC 2. Voltage Noise Density vs.
Frequency

100

10

TOTAL NOISE – nV/ Hz

1

TA = 25C

= 15V

V

S

AT 10Hz

AT 1kHz

RESISTOR NOISE ONLY

SOURCE RESISTANCE – 

R

R1

R2

S

– 2R1

10k100 1k

TPC 5. Total Noise vs. Source Resistance

100

741

10

VOLTAGE NOISE – nV/ Hz

1

1

I/F CORNER =

2.7Hz

INSTRUMENTATION

I/F CORNER

LOW NOISE

OP37

I/F CORNER

RANGE TO DC

10 100 1k

FREQUENCY – Hz

AUDIO OP AMP

AUDIO RANGE

TO 20kHz

TPC 3. A Comparison of Op Amp
Voltage Noise Spectra

5

4

3

2

VOLTAGE NOISE – nV/ Hz

1

–50 –25 0 25 50 75 100 125

AT 10Hz

AT 1kHz

TEMPERATURE – C

VS = 15V

TPC 6. Voltage Noise Density vs.
Temperature

5

T

= 25C

A

4

3

2

VOLTAGE NOISE – nV/ Hz

1

010 40

TOTAL SUPPLY VOLTAGE (V+ – V–) – Volts

AT 10Hz

AT 1kHz

20 30

TPC 7. Voltage Noise Density vs.
Supply Voltage

REV. A

10.0

1.0

CURRENT NOISE – pA/ Hz

0.1

I/F CORNER = 140Hz

10 10k

100 1k

FREQUENCY – Hz

TPC 8. Current Noise Density vs.
Frequency

–7–

5.0

4.0

TA = +125C

3.0

TA = –55C

2.0

SUPPLY CURRENT – mA

1.0

TA = +25C

5

15 25 35 45

TOTAL SUPPLY VOLTAGE – Volts

TPC 9. Supply Current vs. Supply
Voltage

OP37

60

50

40

30
20

10

0

–10

–20

–30

OFFSET VOLTAGE – V

–40

TRIMMING WITH
10k POT DOES

–50

NOT CHANGE

–60

TCV

OS

–70

–50 –25 0 25 50 75 100 125 150 175

–75

TEMPERATURE – C

OP37C

OP37B

OP37A

OP37B
OP37A

OP37A

OP37B

OP37C

TPC 10. Offset Voltage Drift of Eight

Representative Units vs. Temperature

OPEN-LOOP GAIN – dB

30

25

TA =
25C

20

15

10

5

0

–20

= 70C

T

A

THERMAL SHOCK
RESPONSE BAND

DEVICE IMMERSED
IN 70C OIL BATH

02040

TIME – Seconds

VS = +15V

60 80

100

6

4

2

0

–2

–4

–6

6

4

2

0

–2

CHANGE IN OFFSET VOLTAGE – V

–4

–6

0

1234567

TIME – MONTHS

TPC 11. Long-Term Offset Voltage
Drift of Six Representative Units

INPUT BIAS CURRENT – nA

50

40

30

20

10

0

OP37C

OP37B

–50

–25 0 25 50 75 100 125 150

TEMPERATURE – C

VS = +15V

OP37A

TA = 25C

= 15V

V

S

10

OP37C/G

OP37F

5

CHANGE IN INPUT OFFSET VOLTAGE – V

1

01 4

TIME AFTER POWER ON – MINUTES

23

OP37A/E

5

TPC 12. Warm Up Offset Voltage Drift

50

40

30

20

OP37C

10

OP37B

INPUT OFFSET CURRENT – nA

0

–75

–50 –25 0 25 50 75 100 125

OP37A

TEMPERATURE – C

VS = 15V

TPC 13. Offset Voltage Change Due
to Thermal Shock

OPEN-LOOP VOLTAGE GAIN – dB

140

120

100

80

60

40

20

0

1

2103104105106107108

10

10

FREQUENCY – Hz

TA = 25C

= 15V

V

S

2k

R

L

TPC 16. Open-Loop Gain vs. Frequency

TPC 14. Input Bias Current vs. Temperature

80

75

70

65

60

PHASE MARGIN – DEG

55

30

25

20

15

SLEW RATE – V/s

10

–50

–25 0 25 50 75 100 125

M

GBW

SLEW

TEMPERATURE – C

VS = 15V

90

85

80

75

70

65

60

55

50

45

40

TPC 17. Slew Rate, Gain Bandwidth

Product, Phase Margin vs. Temperature

TPC 15. Input Offset Current vs.
Temperature

60

50

40

30

20

F = 10kHz

GAIN – dB

10

0

GAIN-BANDWIDTH PRODUCT – MHz

–10

100k 1M 10M 100M

PHASE

MARGIN

FREQUENCY – Hz

= 71

TA = 25C

= 15V

V

S

AV = 5

TPC 18. Gain, Phase Shift vs. Frequency

–80

–100

–120

–140

–160

–180

–200

–220

PHASE SHIFT – Degrees

–8–

REV. A

OP37

20mV

200ns

+50mV

0V

–50mV

TA = 25C
V

S

= 15V

A

V

= +5

(1k, 250)

2.5
TA = 25C

2.0

RL = 2k

1.5

RL = 1k

1.0

OPEN-LOOP GAIN – V/V

0.5

0

010 40

TOTAL SUPPLY VOLTAGE – Volts

20 30

50

TPC 19. Open-Loop Voltage Gain vs.
Supply Voltage

80

60

40

28

24

20

16

12

8

4

PEAK-TO-PEAK AMPLITUDE – Volts

0

4

10

5

10
FREQUENCY – Hz

6

10

TA = 25C

= 15V

V

S

10

TPC 20. Maximum Output Swing vs.
Frequency

5V

+10V

0V

1µs

18

16

POSITIVE

14

12

10

8

6

4

MAXIMUM OUTPUT – Volts

2

0

7

–2

100

SWING

NEGATIVE
SWING

LOAD RESISTANCE – 

1k 10k

TA = 25C

= 15V

V

S

TPC 21. Maximum Output Voltage
vs. Load Resistance

PERCENT OVERSHOOT

20

0

0 500 2000

VS = 15V

= 20mV

V

IN

= +5 (1k, 250)

A

V

1000 1500

CAPACITIVE LOAD – pF

TPC 22. Small-Signal Overshoot vs.
Capacitive Load

60

TA = 25C

= 15V

V

S

50

40

30

20

SHORT-CIRCUIT CURRENT – mA

10

01 4

TIME FROM OUTPUT SHORTED TO

I

(+)

SC

I

(–)

SC

23 5

GROUND – MINUTES

TPC 25. Short-Circuit Current vs. Time

–10V

TA = 25C

= 15V

V

S

= +5 (1k, 250)

A

V

TPC 23. Large-Signal Transient
Response

140

120

100

CMRR – dB

80

60

40

1k

10k 100k 1M 10M

FREQUENCY – Hz

VS = 15V

= 25C

T

A

= 10V

V

CM

TPC 26. CMRR vs. Frequency

TPC 24. Small-Signal Transient
Response

16

12

8

4

0

–4

–8

COMMON-MODE RANGE – Volts

–12

–16

0 5

TA = +25C

SUPPLY VOLTAGE – Volts

TA = –55C

TA = +125C

TA = –55C

TA = +25C

= +125C

T

A

10 15 20

TPC 27. Common-Mode Input Range
vs. Supply Voltage

REV. A

–9–

OP37

0.1F

100k

OP37

10

D.U.T.

VO LTAG E

GAIN

= 50,000

4.7F

2k

OP12

100k

0.1F

24.3k

4.3k

2.2F

22F

SCOPE  1

= 1M

R

IN

110k

TPC 28. Noise Test Circuit (0.1 Hz to
10 Hz)

POWER SUPPLY REJECTION RATIO – dB

160

140

120

100

80

60

40

20

0

1

10 100 1k 10k 100k 1M 10M 100M

NEGATIVE
SWING

POSITIVE

SWING

FREQUENCY – Hz

TA = 25C

TPC 31. PSRP vs. Frequency

1 SEC/DIV

TPC 29. Low-Frequency Noise

19

TA = 25C

= 15V

V

S

= 5

A

V

18

= 20V p-p

V

O

17

SLEW RATE – V/V

16

15

100 1k 10k 100k

LOAD RESISTANCE – 

TPC 32. Slew Rate vs. Load

2.4
TA = 25C

2.2

= 15V

V

S

2.0

1.8

1.6

1.4

1.2

1.0

0.8

OPEN-LOOP VOLTAGE GAIN – V/V

0.6

0.4

100 1k 10k 100k

LOAD RESISTANCE – 

TPC 30. Open-Loop Voltage Gain vs.
Load Resistance

20

VOLTAGE NOISE – V/ s

15

10

5

0

3

TA = 25C
A

VCL

RISE

= 5

FA LL

6 9 12 15 18 21

SUPPLY VOLTAGE – Volts

TPC 33. Slew Rate vs. Supply Voltage

–10–

REV. A

OP37

R7
100k

C1

100pF

R1

5k

0.1%

R3

390

R2

100

R4

5k

0.1%

INPUT (+)

INPUT (–)

R5

500

0.1%

R6

500

0.1%

R8

20k

0.1%

R9

19.8k

R10
500

V

OUT

NOTES:
TRIM R2 FOR A

VCL

= 1000

TRIM R10 FOR dc CMRR
TRIM R7 FOR MINIMUM V

OUT

AT VCM = 20V p-p, 10kHz

+

–

OP37

+

–

OP37

+

–

OP37

APPLICATIONS INFORMATION

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
circuitry is in use, it should be modified

conventional 741 nulling

or removed to ensure

Noise Measurements

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 device has to be warmed-up forat least five minutes. As

correct OP37 operation. OP37 offset voltage may be nulled to
zero (or other desired setting) using a potentiometer (see offset
nulling circuit).

The OP37 provides stable operation with load capacitances of
up to 1000 pF and ±10 V swings; larger capacitances should be

• For similar reasons, the device has to be well-shielded from

decoupled with a 50 Ω resistor inside the feedback loop. Closed
loop gain must be at least five. For closed loop gain between five

• Sudden motion in the vicinity of the device can also

to ten, the designer should consider both the OP27 and the OP37.
For gains above ten, the OP37 has a clear advantage over the

• The test time to measure 0.1 Hz to l0 Hz noise should not

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 R

–

OP37

+

P

V+

OUTPUT

• A noise-voltage-density test is recommended when measuring

Optimizing Linearity

Best linearity will be obtained by designing for the minimum
output current required for the application. High gain and

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 V
potentiometer may be used. TCV

is necessary, a 10 kΩ trim

OS

is not degraded (see offset

OS

nulling circuit). Other potentiometer values from 1 kΩ to 1 MΩ
can be used with a slight degradation (0.1 µV/°C to 0.2 µV/°C) of

. Trimming to a value other than zero creates a drift of

TCV

OS

approximately (VOS/300) µV/°C. For example, the change in TCV
will be 0.33 µV/°C if VOS is adjusted to 100 µV. The offset voltage
adjustment range with a 10 kΩ potentiometer is ±4 mV. If smaller
adjustment range is required, the nulling sensitivity can be reduced

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 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
product of 800 MHz. The full-power bandwidth

OS

output is 250 kHz. Potentiometer R7 provides quadrature
trimming to optimize the instrumentation amplifier’s ac common­mode rejection.

by using a smaller pot in conjunction with fixed resistors. For
example, the network below will have a ±280 µV adjustment range.

shown in the warm-up drift curve, the offset voltage typically
changes 4 µV due to increasing chip temperature after power up.
In the ten second measurement interval, these temperature­induced effects can exceed tens of nanovolts.

air currents. Shielding minimizes thermocouple effects.

“feedthrough” to increase the observed noise.

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.

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.

gain bandwidth

for a 20 V p-p

REV. A

1

V+

Figure 2. TBD

Figure 3. Burn-In Circuit

+18V

OP37

–18V

84.7k4.7k 1k POT

Figure 4a. TBD

–11–

OP37

140

RS = 0

RS = 100,

FREQUENCY – Hz

CMRR – dB

120

100

80

60

40

10

1k UNBALANCED

100 1k 10k 100k 1M

Figure 4b. TBD

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 25°C. 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 I

TA = 25C

= 15V

V

S

= 20V p-p

V

CM

AC TRIM @ 10kHz

= 0

R

S

RS = 1k
BALANCED

. TCVOS of

B

Figure 6. Peak-to-Peak Noise (0.1 Hz to 10 Hz) vs. Source
Resistance (Includes Resistor Noise)

At RS < 1 kΩ key the OP37’s low voltage noise is maintained.
With R
resistor noise rather than current or voltage noise. It is only
beyond Rs of 20kil 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.
crossover
in the 15 kΩ to 40 kΩ region.

previous designs have made direct coupling difficult, if not
impossible, to use.

100

50

1

OP08/108

OP07

10

5

5534

TOTAL NOISE – nV/ Hz

OP27/37

REGISTER

1

50 10k

NOISE ONLY

100 50k

500 1k 5k

RS – SOURCE RESISTANCE – 

1 RS UNMATCHED

= RS1 = 10k, RS2 = 0

e.g. R

S

MATCHED

2 R

S

= 10k, RS1 = RS2 = 5k

e.g. R

S

R

S1

R

S2

2

Figure 7. !0 Hz Noise vs. Source resistance (Inlcludes
Resistor Noise)

Figure 6 shows the 0.1 Hz to 10 Hz peak-to-peak noise. Here

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 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 OP-07
occurs in the 3 kΩ to 5 kΩ range depending on whether bal­anced or unbalanced source resistors are used (at 3 kΩ the I
I

OS

Therefore, for low-frequency applications, the OP07 is better
than the OP27/37 when Rs > 3 kΩ. The only exception is when
gain error is important. Figure 3 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.

the vertical scale by the square-root of the bandwidth.

1k

OP08/108

500

5534

OP07

100

OP27/37

p-p NOISE – nV

50

REGISTER

10

50 10k

< 1 kΩ, total noise increases, but is dominated by the

S

NOISE ONLY

100 50k

RS – SOURCE RESISTANCE – 

1

2

1 RS UNMATCHED
e.g. RS = RS1 = 10k, RS2 = 0

MATCHED

2 R

S

= 10k, RS1 = RS2 = 5k

e.g. R

S

500 1k 5k

R

S1

R

S2

between the OP37 and OP07 and OP08 noise occurs

100

50

OP08/108

OP07

10

5534

5

TOTAL NOISE – nV/ Hz

OP27/37

REGISTER

1

50 10k

NOISE ONLY

100 50k

500 1k 5k

RS – SOURCE RESISTANCE – 

1 RS UNMATCHED

= RS1 = 10k, RS2 = 0

e.g. R

S

2 R

MATCHED

S

= 10k, RS1 = RS2 = 5k

e.g. R

S

1

2

R

S1

R

S2

error also can be three times the VOS spec.).

The

.

B

–12–

REV. A

OP37

Table I. TBD

Source

Device Impedance Comments

Straln Gauge <500 Ω Typically used in low-

frequency

by only 0.7 dB. With a 1 kΩ 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:

applications.

Magnetic <1500 Ω
Tapehead

Magnetic <1500 Ω Similar need for low I
Phonograph
Cartridges

Linear Variable <1500 Ω Used in rugged servo-feedback
Differential
Transformer is 400 Hz to 5 kHz.

Audio Applications

The following applications information has been abstracted from
a PMI article in the 12/20/80 issue of Electronic Design magazine
and updated.

Low IB very important to reduce
set-magnetization problems when
direct coupling is used. OP37
I

can be neglected.

B

in direct

B

coupled applications. OP47 will not
introduce any self-magnetization
problem.

applications. Bandwidth of interest

C4 (2)
220F

++

R5

100k

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.

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,
at frequencies up to 20 kHz.

Capacitor C3 and resistor R4form 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.

A preamplifier for NAB tape playback is similar to an RIAA

MOVING MAGNET

CARTRIDGE INPUT

Ra

47.5k

Ca
150pF

A1

OP27

R1

97.6k

R3
100

LF ROLLOFF

C3

0.47F

R2

7.87k

G = 1kHz GAIN

= 0.101 ( )

= 98.677 (39.9dB) AS SHOWN

C1

0.03F

C2

0.01F

1 +

OUT IN

R4

75k

R1
R3

OUTPUT

phono preamp, though more gain is typically demanded, along
with equalization requiring a heavy low-frequency boost. The
circuit In Figure 4 can be readily modified for tape use, as
shown by Figure 5.

Figure 8. TBD

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 net-

with standard component values. The popular method to

work
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 µs, 318 µs, and 75 µs.

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 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 Ω, which generates a voltage noise of

While the tape-equalization requirement has a flat high frequency
gain above 3 kHz (t2 = 50 µs), 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 R
optimize frequency response for non ideal tape head perfor­mance and other factors.

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
put
can

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 µin.
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

1.3 nV/√Hz. The noise increases the 3.2 nV/√Hz of the amplifier

G

=+



0 101 1

.






R

1



R



3

it will produce less than 0.03% total harmonic distortion

TA P E

HEAD

–

OP37

Ca

Ra

+

R2

5k

100k

R1

33k

0.01F

0.47F

T1 = 3180s
T2 = 50s

15k

Figure 9. TBD

and R2 to

A

5

out-

offset is just over 500 mV. A single 0.47 µF output capacitor

block this level without affecting the dynamic range.

REV. A

–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.

In addition, the dc resistance of the head should be carefully

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.

controlled, and preferably below 1 kΩ. 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.

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 kΩ.
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, R

, may be necessary, if the microphone is to be

P

unplugged. Otherwise the 100% feedback from the open input
may cause the amplifier to oscillate.

R1

1k

R3

316k

C1

5F

R6

100

Capacitor C2 and resistor R2 form a 2 µs time constant in this
circuit, as recommended for optimum transient response by
the
unity-gain
stant is not necessary, C2 can be deleted, allowing the faster
OP37 to be employed.

Some comment on noise is appropriate to understand the
capability of this circuit. A 150 Ω resistor and R1 and R2 gain

LOW IMPEDANCE

MICROPHONE INPUT

(Z = 50 TO 200 )

R3

R4

=

R1

R2

R2

1k

Rp
30k

–

OP37

+

R4

316k

R7
10k

OUTPUT

resistors connected to a noiseless amplifier will generate 220 nV

Figure 10. TBD

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 µV in a 20 kHz noise bandwidth,
or nearly 61 dB below a l mV input signal. Measurements confirm
this predicted performance.

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,
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,

2. Jung, W.G., IC Op Amp Cookbook, 2nd Ed., H.W. Sams and Company,

3. Jung, W.G., Audio /C Op Amp Applications, 2nd Ed., H.W. Sams and Com-

4. Jung, W.G., and Marsh, R.M., “Picking Capacitors.” Audio, February &

5. Otala, M., “Feedback-Generated Phase Nonlinearity in Audio Amplifiers,”

For applications demanding appreciably lower noise, a high quality
microphone-transformer-coupled preamp (Figure 11) incorporates

6. Stout, D.F., and Kaufman, M., Handbook of Operational Amplifier Circuit

the internally compensated. T1 is a JE-115K-E 150 Ω/15 kΩ
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.

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

C2

1800pF

150

SOURCE

T1*

R1

121

R3

100

R2

1100

A1

OP27

*

T1 – JENSEN JE – 115K – E

JENSEN TRANSFORMERS
10735 BURBANK BLVD.
N. HOLLYWOOD, CA 91601

OUTPUT

Figure 11. TBD

transformer manufacturer. With C2 in use, A1 must have

stability. For situations where the 2 µs time con-

the

p. 458-4S1.

1980.

pany, 1978.

March, 1980.

London AES Convention, March 1980, preprint 197B.

Design, New York, McGraw Hill, 1976.

–14–

REV. A

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Hermetic DIP

(Z Suffix)

OP37

PIN 1

0.200 (5.08)
MAX

0.200 (5.08)

0.125 (3.18)

PIN 1

0.210
(5.33)

MAX

0.160 (4.06)

0.115 (2.93)

0.022 (0.558)

0.014 (0.356)

0.005 (0.13)
MIN

85

1

0.100 (2.54) BSC

0.405 (10.29) MAX

0.023 (0.58)

0.014 (0.36)

0.070 (1.78)

0.030 (0.76)

0.430 (10.92)

0.348 (8.84)

8

14

0.100 (2.54)
BSC

0.070 (1.77)

0.045 (1.15)

0.055 (1.4)
MAX

0.310 (7.87)

0.220 (5.59)

4

0.060 (1.52)

0.015 (0.38)

0.150
(3.81)
MIN

SEATING
PLANE

Epoxy Mini-Dip

(P Suffix)

5

0.280 (7.11)

0.240 (6.10)

0.325 (8.25)

0.130
(3.30)
MIN

0.300 (7.62)

0.060 (1.52)

0.015 (0.38)

SEATING
PLANE

0.320 (8.13)

0.290 (7.37)

15°

0°

0.015 (0.38)

0.008 (0.20)

0.195 (4.95)

0.115 (2.93)

0.015 (0.381)

0.008 (0.204)

REV. A

0.1574 (4.00)

0.1497 (3.80)

PIN 1

0.0098 (0.25)

0.0040 (0.10)

SEATING

0.1968 (5.00)

0.1890 (4.80)

85

0.0500 (1.27)
BSC

PLANE

0.2440 (6.20)

0.2284 (5.80)

41

0.0192 (0.49)

0.0138 (0.35)

8-Lead SO

(S Suffix)

0.0688 (1.75)

0.0532 (1.35)

0.0098 (0.25)

0.0075 (0.19)

–15–

0.0196 (0.50)

0.0099 (0.25)

8

0.0500 (1.27)

0

0.0160 (0.41)

 45

OP37

Revision History

Location Page

Data Sheet changed from REV. B to REV. C.

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

Edits to APPLICATIONS INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

C00319–0–2/02(A)

–16–

PRINTED IN U.S.A.

REV. A