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 b55§C to a125§C temperature range.
The devices operate with supply voltages from g2V to g20V 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 b55§C to a125§C, the LM208 from b25§C to a85§C, and the LM308 from 0§C to a70§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 |
Alternate* Frequency Compensation |
TL/H/7758 ± 1 |
TL/H/7758 ± 2 |
**Bandwidth and slew rate are proportional to 1/Cf |
*Improves rejection of power supply noise by a factor of ten. |
|
**Bandwidth and slew rate are proportional to 1/Cs |
Feedforward Compensation
TL/H/7758 ± 3
Amplifiers Operational LM108/LM208/LM308
C1995 National Semiconductor Corporation |
TL/H/7758 |
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§C to a125§C |
0§C to a70§C |
(LM208) |
b25§C to a 85§C |
|
Storage Temperature Range |
b65§C to a150§C |
b65§C to a150§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 |
TA e 25§C |
|
|
0.7 |
|
2.0 |
|
2.0 |
7.5 |
mV |
Input Offset Current |
TA e 25§C |
|
|
0.05 |
|
0.2 |
|
0.2 |
1 |
nA |
Input Bias Current |
TA e 25§C |
|
|
0.8 |
|
2.0 |
|
1.5 |
7 |
nA |
Input Resistance |
TA e 25§C |
30 |
|
70 |
|
|
10 |
40 |
|
MX |
Supply Current |
TA e 25§C |
|
|
0.3 |
|
0.6 |
|
0.3 |
0.8 |
mA |
Large Signal Voltage |
TA e 25§C, VS e g15V |
50 |
|
300 |
|
|
25 |
300 |
|
V/mV |
Gain |
VOUT e g10V, RL t 10 kX |
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
||
Input Offset Voltage |
|
|
|
|
|
3.0 |
|
|
10 |
mV |
Average Temperature |
|
|
|
|
|
|
|
|
|
mV/§C |
Coefficient of Input |
|
|
|
3.0 |
|
15 |
|
6.0 |
30 |
|
Offset Voltage |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Input Offset Current |
|
|
|
|
|
0.4 |
|
|
1.5 |
nA |
Average Temperature |
|
|
|
|
|
|
|
|
|
pA/§C |
Coefficient of Input |
|
|
|
0.5 |
|
2.5 |
|
2.0 |
10 |
|
Offset Current |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Input Bias Current |
|
|
|
|
|
3.0 |
|
|
10 |
nA |
Supply Current |
TA e a125§C |
|
|
0.15 |
|
0.4 |
|
|
|
mA |
Large Signal Voltage |
VS e g15V, VOUT e g10V |
25 |
|
|
|
|
15 |
|
|
V/mV |
Gain |
RL t 10 kX |
|
|
|
|
|
|
|||
|
|
|
|
|
|
|
|
|
||
Output Voltage Swing |
VS e g15V, RL e 10 kX |
g13 |
|
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 |
VS e g15V |
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 s VS s g20V and b55§C s TA s a125§C, unless otherwise specified. With the LM208, however, all temperature specifications are limited to b25§C s TA s 85§C, and for the LM308 they are limited to 0§C s TA 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
Loading...