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TL/H/7758
LM108/LM208/LM308 Operational Amplifiers
December 1994
LM108/LM208/LM308 Operational Amplifiers
General Description
The LM108 series are precision operational amplifiers having specifications a factor of ten better than FET amplifiers
over a
b
55§Ctoa125§C temperature range.
The devices operate with supply voltages fromg2V to
g
20V and have sufficient supply rejection to use unregulated 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 bypass capacitors unnecessary.
The low current error of the LM108 series makes possible
many designs that are not practical with conventional amplifiers. In fact, it operates from 10 MX source 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 using capacitors no larger than 1 mF.
The LM108 is guaranteed from
b
55§Ctoa125§C, the
LM208 from
b
25§Ctoa85§C, and the LM308 from 0§Cto
a
70§C.
Features
Y
Maximum input bias current of 3.0 nA over temperature
Y
Offset current less than 400 pA over temperature
Y
Supply current of only 300 mA, even in saturation
Y
Guaranteed drift characteristics
Compensation Circuits
Standard Compensation Circuit
C
f
t
R1 C
O
R1aR2
C
O
e
30 pF
TL/H/7758– 1
**Bandwidth and slew rate are proportional to 1/C
f
Alternate* Frequency Compensation
TL/H/7758– 2
*Improves rejection of power supply noise by a factor of ten.
**Bandwidth and slew rate are proportional to 1/C
s
Feedforward Compensation
TL/H/7758– 3
C
1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.
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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
g
20V
g
18V
Power Dissipation (Note 1) 500 mW 500 mW
Differential Input Current (Note 2)
g
10 mA
g
10 mA
Input Voltage (Note 3)
g
15V
g
15V
Output Short-Circuit Duration Continuous Continuous
Operating Temperature Range (LM108)
b
55§Ctoa125§C0
§
Ctoa70§C
(LM208)
b
25§Ctoa85§C
Storage Temperature Range
b
65§Ctoa150§C
b
65§Ctoa150§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 T
A
e
25§C 0.7 2.0 2.0 7.5 mV
Input Offset Current T
A
e
25§C 0.05 0.2 0.2 1 nA
Input Bias Current T
A
e
25§C 0.8 2.0 1.5 7 nA
Input Resistance T
A
e
25§C 3070 1040 MX
Supply Current T
A
e
25§C 0.3 0.6 0.3 0.8 mA
Large Signal Voltage T
A
e
25§C, V
S
e
g
15V
50 300 25 300 V/mV
Gain V
OUT
e
g
10V, R
L
t
10 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 T
A
ea
125§C 0.15 0.4 mA
Large Signal Voltage V
S
e
g
15V, V
OUT
e
g
10V
25 15 V/mV
Gain R
L
t
10 kX
Output Voltage Swing V
S
e
g
15V, R
L
e
10 kX
g
13
g
14
g
13
g
14 V
2
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Electrical Characteristics (Note 4) (Continued)
Parameter Condition
LM108/LM208 LM308
Units
Min Typ Max Min Typ Max
Input Voltage Range V
S
e
g
15V
g
13.5
g
14 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
g
15V, the absolute maximum input voltage is equal to the supply voltage.
Note 4: These specifications apply for
g
5VsV
S
s
g
20V andb55§CsT
A
s
a
125§C, unless otherwise specified. With the LM208, however, all temperature
specifications are limited to
b
25§CsT
A
s
85§C, and for the LM308 they are limited to 0§CsT
A
s
70§C.
Note 5: Refer to RETS108X for LM108 military specifications and RETs 108AX for LM108A military specifications.
Note 6: Human body model, 1.5 kX in series with 100 pF.
Schematic Diagram
TL/H/7758– 8
3
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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/7758– 6
4
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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/7758– 7
5
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Typical Applications
Sample and Hold
²
Teflon polyethylene or
polycarbonate dielectric
capacitor
Worst case drift less than
2.5 mV/sec
TL/H/7758– 4
High Speed Amplifier with Low Drift and Low Input Current
TL/H/7758– 5
6
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Typical Applications (Continued)
Fast
²
Summing Amplifier
*In addition to increasing
²
Power Bandwidth: 250 KHz
speed, the LM101A raises Small Signal Bandwidth: 3.5 MHz
high and low frequency Slew Rate: 10V/mS
gain, increases output
³
C5
e
6c10
b
8
R
f
drive capability and eliminates
thermal feedback.
TL/H/7758– 12
Connection Diagrams
Metal Can Package
TL/H/7758– 13
*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/7758– 15
Top View
Order Number LM108J-8/883, LM308M or LM308N
See NS Package Number J08A, M08A or N08E
TL/H/7758– 16
Top View
Order Number LM108J/883
See NS Package Number J14A
TL/H/7758– 17
Order Number LM108W/883
See NS Package Number W10A
²
Also available per JM38510/10104
7
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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
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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
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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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failure to perform, when properly used in accordance support device or system, or to affect its safety or
with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.
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