www.fairchildsemi.com
LM108A/LH2108A
Precision Operational Amplifiers
Features
•
•
•
•
•
•
•
•
•
Low input bias current — 2 nA
Low input offset current — 200 pA
Low input offset voltage — 500mV
Low input offset drift — 5
mV/°C
Wide supply range —
±3V
to
±20V
Low supply current — 0.6 mA
High PSRR — 96 dB
High CMRR — 96 dB
MIL-STD-883B available
Description
The LM108A operational amplifiers features low input bias
current combined with the advantages of bipolar transistor
construction; input offset voltages and currents are kept
low over a wide range of temperature and supply voltage.
Fairchild Semiconductor’s superbeta bipolar manufacturing
process includes extra treatment at epitaxial growth to ensure
low input voltage noise.
The LH2108 consists of two LM108 ICs in one 16-lead DIP.
The “A” versions meet tighter electrical specifications than
the plain versions. All types are available with 883B military
screening.
Rev 1.0.0
LM108A/LH2108A
PRODUCT SPECIFICATION
Pin Assignments
8-Lead Metal Can
(Top View)
Comp
Comp
8
1
2
3
4
-V
S
5
NC
-V
S
4
5
NS
7
+V
S
Comp 1
-Input 2
-Input
+Input
6
Output
+Input 3
6
Output
8
7
Comp
+V
S
8-Lead DIP
(Top View)
65-108A-01
16-Lead DIP
(Top View)
+V
S
(A) 1
Comp (A) 2
Comp/V
OS
Trim (A) 3
-Input (A) 4
+Input (A) 5
-V
S
6
NC 7
Output (B) 8
65-108A-02
16 Output (A)
15 NC
14 V
OS
Trim
13 +Input (B)
12 -Input (B)
11 Comp/V
OS
Trim (B)
10 Comp (B)
9 +V
S
(B)
Absolute Maximum Ratings
Parameter
Supply Voltage
Differential Input Current
1
Input Voltage
2
Output Short-Circuit Duration
2
Operating Temperature Range
Storage Temperature Range
Lead Soldering Temperature (60 seconds)
-55
-65
Min.
Max.
±20
±10
±15
Continuous
+125
+150
+300
°C
°C
°C
Units
V
mA
V
Notes:
1. The inputs are shunted with back-to-back diodes for overvoltage protection. Therefore, if a differential input voltage in excess
of 1V is applied between the inputs, excessive current will flow, unless some limiting resistance is provided.
2. For supply voltages less than
±15V,
the absolute maximum input voltage is equal to the supply voltage.
2
PRODUCT SPECIFICATION
LM108A/LH2108A
Thermal Characteristics
Parameter
Maximum Junction Temperature
Max. P
D
T
A
< 50°C
Thermal Resistance,
q
JC
Thermal Resistance,
q
JA
For T
A
> 50°C Derate at
8-Lead
Metal Can
+175°C
658 mW
50°C/W
190°C/W
5.26 mW/°C
8-Lead
Ceramic DIP
+175°C
833 mW
45°C/W
150°C/W
8.33 mW/°C
16-Lead
Ceramic DIP
+175°C
1042 mW
60°C/W
120°C/W
8.38 mW/°C
Electrical Characteristics
±5V, £
V
S
£ ±20V
and T
A
£
+25°C unless otherwise noted
LM108A/LH2108A
Parameters
Input Offset Voltage
Input Offset Current
Input Bias Current
Input Resistance1
Large Signal Voltage
Gain
Supply Current
Input Offset Voltage
Avg. Input Offset
Voltage Drift
2
Input Offset Current
Avg. lnput Offset
Current Drift
2
Input Bias Current
Large Signal Voltage
Gain
Output Voltage Swing
Input Voltage Range
Common Mode
Rejection Ratio
Power Supply Rejection
Ratio
Supply Current
V
S
=
±15V,
V
OUT
=
±10V,
R
L
³
10 KW
R
L
³
10 KW,
V
S
=
±20V
V
S
=
±15V
V
CM
=
±13.5V,
V
S
=
±15V
V
S
=
±15V
Each Amplifier
40
V
S
=
±15V,
V
OUT
±10V,
R
L
³
10KW
Each Amplifier
30
80
Test Conditlons
Min.
Typ.
0.3
0.05
0.8
70
300
Max.
0.5
0.2
2.0
30
50
LM108/LH2108
Min.
Typ.
0.7
0.05
0.8
70
300
Max.
2.0
0.2
2.0
Units
mV
nA
nA
MW
V/mV
0.3
0.4
1.0
0.1
0.5
1.0
200
0.6
1.0
5.0
0.4
2.5
3.0
25
0.3
1.0
3.0
0.1
0.5
1.0
200
0.6
3.0
15
0.4
2.5
3.0
mA
mV
mV/°C
nA
pA/°C
nA
V/mV
±5V, £
V
S
£ ±20V;
-55°C
£
T
A
£
+25°C unless otherwise noted
±16
±13.5
96
96
±18
±16
±13.5
±18
V
V
110
110
0.6
85
80
100
96
0.6
dB
dB
mA
Notes:
1. Guaranteed by input bias current specification.
2. Sample tested.
3
LM108A/LH2108A
PRODUCT SPECIFICATION
Typical Applications
The LM108 series has very low input offset and bias
currents; the user is cautioned that printed circuit board
leakages can produce significant errors especially at high
board temperatures. Careful attention to board layout and
cleaning procedure is required to achieve the LM108A’s
rated performance. It is suggested that board leakage be
minimized by encircling the input pins with a guard ring
maintained at a potential close to that of the inputs. The
guard ring should be driven by a low impedance source such
as an amplifier’s output or ground.
+V
S
R3
50K
R1
200K
R4
R2
100
-V
S
2
3
R5
-V
IN
6
R1
2
R2
LM108
V
OUT
+V
IN
Range = ±V
S
R3
3
LM108
8
1 C *
F
6
V
OUT
+V
IN
Gain = 1 +
(
R2
(
R1
C
F
>
(
R4R5R2
(
+
65-2652
R1
(
R1 +C
(
R2
L
*Bandwidth and slew rate
are proportional to 1/C
F
C
L
= Load Capacitance
65-2653
Figure 1. Offset Adjustment for Non-Inverting Amplifiers
Figure 2. Standard Compensation Circuit
R2
-V
IN
R1
-V
IN
+V
IN
R1
2
3
LM108
6
+V
S
R3
R4
10
-V
S
R5
20K
R6
25K
Range = ±V
S
Gain =
R2
R1
65-2654
R1
2
R2
V
OUT
+V
IN
R3
3
LM108
8**
6
V
OUT
C
S
100 pF
R2 = R3 + R4
R5
(
R4
((
R1
R1 + R3
(
*Improves rejection of power supply noise by a factor of 10.
**Bandwidth and slew rate are proportional to 1/C
S
.
65-2655
Figure 3. Offset Adjustment for Differential Amplifiers
Figure 4. Alternate Frequency Compensation
R3
R4
V
IN
+V
S
R5
50K
R1
200K
2
3
LM108
6
V
OUT
V
IN
R1
10K
C2
5 pF
R2
10K
2
3
LM108
8
1
R3
3K
C3
10 pF
65-2651
6
V
OUT
R2
100
-V
S
Range = ±V
S
(
R2
(
R1
65-2650
C1
500 pF
Figure 5. Offset Adjustment for Inverting Amplifiers
Figure 6. Feedforward Compensation
4
PRODUCT SPECIFICATION
LM108A/LH2108A
Mechanical Dimensions
8-Lead TO-99 Metal Can
øD
Symbol
øD1
A
øb
øb1
øD
øD1
øD2
e
e1
F
k
k1
L
L1
L2
Q
a
Notes:
e1
1. (All leads) øb applies between L1 & L2. øb1 applies between
L2 & .500 (12.70mm) from the reference plane. Diameter is
uncontrolled in L1 & beyond .500 (12.70mm) from the
reference plane.
2. Measured from the maximum diameter of the product.
3. Leads having a maximum diameter .019 (.48mm) measured in
gauging plane, .054 (1.37mm) +.001 (.03mm) –.000 (.00mm)
below the reference plane of the product shall be within
.007 (.18mm) of their true position relative to a maximum width
tab.
a
4. The product may be measured by direct methods or by gauge.
5. All leads – increase maximum limit by .003 (.08mm) when lead
finish is applied.
k
k1
Inches
Min.
Max.
Millimeters
Min.
Max.
1, 5
1, 5
Notes
L1
F
Q
A
L2
L
øb
BASE and
SEATING
PLANE
øb1
.165
.185
.016
.019
.016
.021
.335
.375
.305
.335
.110
.160
.200 BSC
.100 BSC
—
.040
.027
.034
.027
.500
—
.045
.750
.050
4.19
4.70
.41
.48
.41
.53
8.51
9.52
7.75
8.51
2.79
4.06
5.08 BSC
2.54 BSC
—
1.02
.69
.86
.69
12.70
—
1.14
19.05
1.27
REFERENCE
PLANE
.250
—
.010
.045
45¡ BSC
6.35
—
.25
1.14
45¡ BSC
2
1
1
1
e
øD2
5
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