LM725 Operational Amplifier

May 1998

LM725
Operational Amplifier
General Description Features
The LM725/LM725A/LM725C are operational amplifiers fea- n High open loop gain 3,000,000
turing superior performance in applications where low noise, n Low input voltage drift 0.6 µV/˚C
low drift, and accurate closed-loop gain are required. With n High common mode rejection 120 dB
high common mode rejection and offset null capability, it is n Low input noise current 0.15 pA/√Hz
especially suited for low level instrumentation applications n Low input offset current 2 nA
over a wide supply voltage range.
n High input voltage range ± 14V
The LM725A has tightened electrical performance with n Wide power supply range ± 3V to ± 22V
higher input accuracy and like the LM725, is guaranteed
n Offset null capability
over a −55˚C to +125˚C temperature range. The LM725C
has slightly relaxed specifications and has its performance n Output short circuit protection
guaranteed over a 0˚C to 70˚C temperature range.

Connection Diagrams

Metal Can Package Dual-In-Line Package

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Order Number LM725CN

See NS Package Number N08E

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Order Number LM725H/883, LM725CH

or LM725AH/883
See NS Package Number H08C

© 1999 National Semiconductor Corporation DS010474 www.national.com

 Absolute Maximum Ratings (Note 1) Lead Temperature
If Military/Aerospace specified devices are required, (Soldering, 10 Sec.) 260˚C
please contact the National Semiconductor Sales Office/ Maximum Junction Temperature 150˚C
Distributors for availability and specifications.
Operating Temperature Range TA(MIN) TA(MAX)
Supply Voltage ± 22V LM725 −55˚C to +125˚C
Internal Power Dissipation (Note 2) 500 mW LM725A −55˚C to +125˚C
Differential Input Voltage ± 5V
LM725C 0˚C to +70˚C
Input Voltage (Note 3) ± 22V
Storage Temperature Range −65˚C to +150˚C

Electrical Characteristics (Note 4)

Parameter Conditions LM725A LM725 LM725C Units
Min Typ Max Min Typ Max Min Typ Max
Input Offset Voltage TA = 25˚C, 0.5 0.5 1.0 0.5 2.5 mV
(Without External Trim) RS ≤ 10 kΩ
Input Offset Current TA = 25˚C 2.0 5.0 2.0 20 2.0 35 nA
Input Bias Current TA = 25˚C 42 80 42 100 42 125 nA
Input Noise Voltage TA = 25˚C
fo = 10 Hz 15 15 15 nV/√Hz
fo = 100 Hz 9.0 9.0 9.0 nV/√Hz
fo = 1 kHz 8.0 8.0 8.0 nV/√Hz
Input Noise Current TA = 25˚C
fo = 10 Hz 1.0 1.0 1.0 pA/√Hz
fo = 100 Hz 0.3 0.3 0.3 pA/√Hz
fo = 1 kHz 0.15 0.15 0.15 pA/√Hz
Input Resistance TA = 25˚C 1.5 1.5 1.5 MΩ
Input Voltage Range TA = 25˚C ± 13.5 ± 14 ± 13.5 ± 14 ± 13.5 ± 14 V
Large Signal Voltage TA = 25˚C,
Gain RL ≥ 2 kΩ, 1000 3000 1000 3000 250 3000 V/mV
VOUT = ± 10V
Common-Mode TA = 25˚C, 120 110 120 94 120 dB
Rejection Ratio RS ≤ 10 kΩ
Power Supply TA = 25˚C, 2.0 5.0 2.0 10 2.0 35 µV/V
Rejection Ratio RS ≤ 10 kΩ
Output Voltage Swing TA = 25˚C,
RL ≥ 10 kΩ ± 12.5 ± 13.5 ± 12 ± 13.5 ± 12 ± 13.5 V
RL ≥ 2 kΩ ± 12.0 ± 13.5 ± 10 ± 13.5 ± 10 ± 13.5 V
Power Consumption TA = 25˚C 80 105 80 105 80 150 mW
Input Offset Voltage RS ≤ 10 kΩ 0.7 1.5 3.5 mV
(Without External Trim)
Average Input Offset RS = 50Ω
Voltage Drift 2.0 2.0 5.0 2.0 µV/˚C
(Without External Trim)
Average Input Offset RS = 50Ω
Voltage Drift 0.6 1.0 0.6 0.6 µV/˚C
(With External Trim)
Input Offset Current TA = TMAX 1.2 4.0 1.2 20 1.2 35 nA
TA = TMIN 7.5 18.0 7.5 40 4.0 50 nA
Average Input Offset 35 90 35 150 10 pA/˚C
Current Drift
Input Bias Current TA = TMAX 20 70 20 100 125 nA
TA = TMIN 80 180 80 200 250 nA

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 Electrical Characteristics (Note 4) (Continued)

Parameter Conditions LM725A LM725 LM725C Units

Min Typ Max Min Typ Max Min Typ Max
Large Signal Voltage RL ≥ 2 kΩ
Gain TA = TMAX 1,000,000 1,000,000 125,000 V/V
RL ≥ 2 kΩ
TA = TMIN 500,000 250,000 125,000 V/V
Common-Mode RS ≤ 10 kΩ 110 100 115 dB
Rejection Ratio
Power Supply RS ≤ 10 kΩ 8.0 20 20 µV/V
Rejection Ratio
Output Voltage Swing RL ≥ 2 kΩ ± 12 ± 10 ± 10 V
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits.
Note 2: Derate at 150˚C/W for operation at ambient temperatures above 75˚C.
Note 3: For supply voltages less than ± 22V, the absolute maximum input voltage is equal to the supply voltage.
Note 4: These specifications apply for VS = ± 15V unless otherwise specified.
Note 5: For Military electrical specifications RETS725AX are available for LM725AH and RETS725X are available for LM725H.

Schematic Diagram

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 Typical Performance Characteristics
Voltage Gain vs Temperature Change in Trimmed Input Untrimmed Input Offset
for Supply Voltages Offset Voltage vs Temperature Voltage vs Temperature

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Input Offset Current Input Bias Current Stabilization Time of

vs Temperature vs Temperature Input Offset Voltage
from Power Turn-On

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Change in Input Input Noise Input Noise

Offset Voltage Due to Voltage vs Frequency Current vs Frequency
Thermal Shock vs Time

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Typical Performance Characteristics (Continued)

Power Consumption Open Loop Frequency Values for Suggested Compen-

vs Temperature Response for Values sation Networks vs Various
of Compensation (Note 6) Close Loop Voltage Gains

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Frequency Response for Output Voltage Swing Transient Response

Various Close Loop vs Frequency (Note 6)
Gain (Note 6)

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Note 6: Performance is shown using recommended compensation networks.

Transient Response Test Circuit

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 Auxiliary Circuits
Voltage Offset
Null Circuit

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Frequency Compensation
Circuit

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Compensation Component Values

AV R1 C1 R2 C2
(Ω) (µF) (Ω) (µF)
10,000 10k 50 pF
1,000 470 0.001
100 47 0.01
10 27 0.05 270 0.0015
1 10 0.05 39 0.02

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Typical Applications
Photodiode Amplifier

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DC Gains = 10,000; 1,000; 100; and 10

Bandwidth = Determined by value of C1

Thermocouple Amplifier

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Note: Indicates ± 1% metal film resistors recommended for temperature stability.

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 Typical Applications (Continued)

± 100V Common Mode Range Differential Amplifier

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Instrumentation Amplifier with High

Common Mode Rejection

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Typical Applications (Continued)

Precision Amplifier AVCL = 1000

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 Physical Dimensions inches (millimeters) unless otherwise noted

Order Number LM725H/883, LM725CH or LM725AH/883

NS Package Number H08C

Order Number LM725CN

NS Package Number N08E

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 LM725 Operational Amplifier
Notes

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