OP77_02 Datasheet, PDF (10/16 Pages) Analog Devices – Next Generation OP07 Ultralow Offset Voltage Operational Amplifier

OP77
200k⍀
50⍀
OP77
V_O
V_OS
=
V_O
4000
Figure 1. Typical Offset Voltage Test Circuit
2.5M⍀
100⍀
100⍀
V+
2
7
3 ^OP77
6 ^3.3k⍀
4
V–
OUTPUT
4.7␮F
( 10Hz FILTER)
INPUT
REFERRED
NOISE
=
VO
25,000
Figure 2. Typical Low-Frequency Noise Test Circuit
–
INPUT ₊
20k⍀
2 ¹⁸
3 ^{OP77 7 6}
4
V–
V+
OUTPUT
Figure 3. Optional Offset Nulling Circuit
100k⍀
+18V
+
* 10␮F _10⍀
2
7
3 ^OP77 6
10k⍀ 10k⍀
4
0.1␮F
10␮F ^* ₊
10⍀ _0.1␮F
–18V
*_{1 PER BOARD}
Figure 4. Burn-In Circuit
10k⍀
100k⍀
1M⍀
V_IN = 10V
10⍀
V_X
R_L
TYPICAL
PRECISION OP AMP
V_Y
–10V 0V
V_X
+10V
A_VO ~ 650V/mV
NOTES
R_L = 2k⍀
1. GAIN NOT CONSTANT. CAUSES NONLINEAR ERRORS.
2. A_VO SPEC IS ONLY PART OF THE SOLUTION.
3. CHECK THE OP AMP PERFORMANCE, ESPECIALLY AT TEMPERATURES.
Figure 5. Open-Loop Gain Linearity
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.
V_Y
–10V
0V
+10V
V_X
A_VO ~ 650V/mV
R_L = 2k⍀
Figure 6. Output Gain Linearity 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.
–10–
REV. C