OP77AJMDA AD [Analog Devices], OP77AJMDA Datasheet - Page 10

• Manufacturer Part Number: OP77AJMDA
• Description: Next Generation OP07 Ultralow Offset Voltage Operational Amplifier
• Manufacturer: AD [Analog Devices]

OP77
Figure 2. Typical Low-Frequency Noise Test Circuit
Figure 1. Typical Offset Voltage Test Circuit
Figure 3. Optional Offset Nulling Circuit
INPUT
100
100
INPUT REFERRED NOISE
–
+
10k
50
10 F
Figure 4. Burn-In Circuit
*
2
*
3
10k
OP77
100k
2.5M
+
+
10 F
2
3
V+
V–
2
3
OP77
7
4
+18V
OP77
–18V
OP77
200k
1
6
7
4
10
10
8
4
20k
V–
=
3.3k
*
25,000
6
7
1 PER BOARD
V O
V
OS
6
0.1 F
0.1 F
=
4000
4.7 F
(
V
O
OUTPUT
10Hz FILTER)
V
V+
OUTPUT
O
–10–
Actual open-loop voltage gain can vary greatly at various output
voltages. All automated testers use endpoint testing and therefore
only show the average gain. This causes errors in high closed-
loop gain circuits. Since this is so difficult for manufacturers to
test, users should make their own evaluation. This simple test
circuit makes it easy. An ideal op amp would show a horizontal
scope trace.
This is the output gain linearity trace for the new OP77. The
output trace is virtually horizontal at all points, assuring extremely
high gain accuracy. The average open-loop gain is truly impres-
sive—approximately 10,000,000.
NOTES
1. GAIN NOT CONSTANT. CAUSES NONLINEAR ERRORS.
2. A
3. CHECK THE OP AMP PERFORMANCE, ESPECIALLY AT TEMPERATURES.
V
IN
VO
10k
= 10V
SPEC IS ONLY PART OF THE SOLUTION.
A
R
VO
L
= 2k
~
650V/mV
Figure 6. Output Gain Linearity Trace
10
1M
Figure 5. Open-Loop Gain Linearity
–10V
100k
R
L
V
X
0V
V
Y
–10V
A
R
PRECISION OP AMP
VO
L
= 2k
~
TYPICAL
650V/mV
+10V
0V
V
Y
REV. C
+10V
V
V
X
X