TL/H/7758
LM108/LM208/LM308 Operational Amplifiers
December 1994
LM108/LM208/LM308 Operational Amplifiers
General Description
The LM108 series are precision operational amplifiers hav-
ing specifications a factor of ten better than FET amplifiers
over a b55§Ctoa
125§C temperature range.
The devices operate with supply voltages from g2V to
g20V and have sufficient supply rejection to use unregulat-
ed supplies. Although the circuit is interchangeable with and
uses the same compensation as the LM101A, an alternate
compensation scheme can be used to make it particularly
insensitive to power supply noise and to make supply by-
pass capacitors unnecessary.
The low current error of the LM108 series makes possible
many designs that are not practical with conventional ampli-
fiers. In fact, it operates from 10 MXsource resistances,
introducing less error than devices like the 709 with 10 kX
sources. Integrators with drifts less than 500 mV/sec and
analog time delays in excess of one hour can be made us-
ing capacitors no larger than 1 mF.
The LM108 is guaranteed from b55§Ctoa
125§C, the
LM208 from b25§Ctoa
85§C, and the LM308 from 0§Cto
a
70§C.
Features
YMaximum input bias current of 3.0 nA over temperature
YOffset current less than 400 pA over temperature
YSupply current of only 300 mA, even in saturation
YGuaranteed drift characteristics
Compensation Circuits
Standard Compensation Circuit
CftR1 CO
R1 aR2
COe30 pF
TL/H/77581
**Bandwidth and slew rate are proportional to 1/Cf
Alternate*Frequency Compensation
TL/H/77582
*Improves rejection of power supply noise by a factor of ten.
**Bandwidth and slew rate are proportional to 1/Cs
Feedforward Compensation
TL/H/77583
C1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.
Absolute Maximum Ratings
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
(Note 5)
LM108/LM208 LM308
Supply Voltage g20V g18V
Power Dissipation (Note 1) 500 mW 500 mW
Differential Input Current (Note 2) g10 mA g10 mA
Input Voltage (Note 3) g15V g15V
Output Short-Circuit Duration Continuous Continuous
Operating Temperature Range (LM108) b55§Ctoa
125§C0
§
Ctoa
70§C
(LM208) b25§Ctoa85§C
Storage Temperature Range b65§Ctoa
150§Cb65§Ctoa
150§C
Lead Temperature (Soldering, 10 sec)
DIP 260§C 260§C
H Package Lead Temp
(Soldering 10 seconds) 300§C 300§C
Soldering Information
Dual-In-Line Package
Soldering (10 seconds) 260§C
Small Outline Package
Vapor Phase (60 seconds) 215§C
Infrared (15 seconds) 220§C
See AN-450 ‘‘Surface Mounting Methods and Their Effect on Product
Reliability’’ for other methods of soldering surface mount devices.
ESD Tolerance (Note 6) 2000V
Electrical Characteristics (Note 4)
Parameter Condition LM108/LM208 LM308 Units
Min Typ Max Min Typ Max
Input Offset Voltage TAe25§C 0.7 2.0 2.0 7.5 mV
Input Offset Current TAe25§C 0.05 0.2 0.2 1 nA
Input Bias Current TAe25§C 0.8 2.0 1.5 7 nA
Input Resistance TAe25§C 3070 1040 MX
Supply Current TAe25§C 0.3 0.6 0.3 0.8 mA
Large Signal Voltage TAe25§C, VSeg15V 50 300 25 300 V/mV
Gain VOUT eg10V, RLt10 kX
Input Offset Voltage 3.0 10 mV
Average Temperature
Coefficient of Input 3.0 15 6.0 30 mV/§C
Offset Voltage
Input Offset Current 0.4 1.5 nA
Average Temperature
Coefficient of Input 0.5 2.5 2.0 10 pA/§C
Offset Current
Input Bias Current 3.0 10 nA
Supply Current TAea
125§C 0.15 0.4 mA
Large Signal Voltage VSeg15V, VOUT eg10V 25 15 V/mV
Gain RLt10 kX
Output Voltage Swing VSeg15V, RLe10 kXg13 g14 g13 g14 V
2
Electrical Characteristics (Note 4) (Continued)
Parameter Condition LM108/LM208 LM308 Units
Min Typ Max Min Typ Max
Input Voltage Range VSeg15V g13.5 g14 V
Common Mode 85 100 80 100 dB
Rejection Ratio
Supply Voltage 80 96 80 96 dB
Rejection Ratio
Note 1: The maximum junction temperature of the LM108 is 150§C, for the LM208, 100§C and for the LM308, 85§C. For operating at elevated temperatures, devices
in the H08 package must be derated based on a thermal resistance of 160§C/W, junction to ambient, or 20§C/W, junction to case. The thermal resistance of the
dual-in-line package is 100§C/W, junction to ambient.
Note 2: The inputs are shunted with back-to-back diodes for overvoltage protection. Therefore, excessive current will flow if a differential input voltage in excess of
1V is applied between the inputs unless some limiting resistance is used.
Note 3: For supply voltages less than g15V, the absolute maximum input voltage is equal to the supply voltage.
Note 4: These specifications apply for g5V sVSsg20V and b55§CsTAsa125§C, unless otherwise specified. With the LM208, however, all temperature
specifications are limited to b25§CsTAs85§C, and for the LM308 they are limited to 0§CsTAs70§C.
Note 5: Refer to RETS108X for LM108 military specifications and RETs 108AX for LM108A military specifications.
Note 6: Human body model, 1.5 kXin series with 100 pF.
Schematic Diagram
TL/H/77588
3
Typical Performance Characteristics LM108/LM208
Input Currents Offset Error Drift Error
Input Noise Voltage Power Supply Rejection Output Impedance
Closed Loop
Voltage Gain Output Swing Supply Current
Frequency Response
Open Loop
Frequency Response
Large Signal
Pulse Response
Voltage Follower
TL/H/77586
4
Typical Performance Characteristics LM308
Input Currents Offset Error Drift Error
Input Noise Voltage Power Supply Rejection Output Impedance
Closed Loop
Voltage Gain Output Swing Supply Current
Frequency Response
Open Loop
Frequency Response
Large Signal
Pulse Response
Voltage Follower
TL/H/77587
5
Typical Applications
Sample and Hold
²Teflon polyethylene or
polycarbonate dielectric
capacitor
Worst case drift less than
2.5 mV/sec
TL/H/77584
High Speed Amplifier with Low Drift and Low Input Current
TL/H/77585
6
Typical Applications (Continued)
Fast²Summing Amplifier
*In addition to increasing ²Power Bandwidth: 250 KHz
speed, the LM101A raises Small Signal Bandwidth: 3.5 MHz
high and low frequency Slew Rate: 10V/mS
gain, increases output
³C5 e6c10b8
Rf
drive capability and eliminates
thermal feedback.
TL/H/775812
Connection Diagrams
Metal Can Package
TL/H/775813
*Package is connected to Pin 4 (Vb)
**Unused pin (no internal connection) to allow for input anti-leakage guard
ring on printed circuit board layout.
Order Number LM108H, LM108H/883,
LM308AH or LM308H
See NS Package Number H08C
Dual-In-Line Package
TL/H/775815
Top View
Order Number LM108J-8/883, LM308M or LM308N
See NS Package Number J08A, M08A or N08E
TL/H/775816
Top View
Order Number LM108J/883
See NS Package Number J14A
TL/H/775817
Order Number LM108W/883
See NS Package Number W10A
²Also available per JM38510/10104
7
Physical Dimensions inches (millimeters)
Ceramic Dual-In-Line Package (J)
Order Number LM108J/883
NS Package Number J08A
Ceramic Dual-In-Line Package (J)
Order Number LM108/883
NS Package Number J14A
8
Physical Dimensions inches (millimeters) (Continued)
Metal Can Package (H)
Order Number LM108H, LM108H/883 or LM308H
NS Package Number H08C
S.O. Package (M)
Order Number LM308M
NS Package Number M08A
9
LM108/LM208/LM308 Operational Amplifiers
Physical Dimensions inches (millimeters) (Continued)
Molded Dual-In-Line Package (N)
Order Number LM308N
NS Package Number N08E
Ceramic Flatpack Package (W)
Order Number LM108AW/883 or
LM108W/883
NS Package Number W10A
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be reasonably expected to result in a significant injury
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