Datasheet

AMP03
–7–
REV. F
System Design Suggested Op Amp
Requirement For A1 and A2
Source Impedance Low, Need Low OP27, OP37
Voltage Noise Performance OP227 (Dual Matched)
OP270 (Dual)
OP271
OP470
OP471
Source Impedance High OP80
(R
S
≥ 15 kΩ). Need Low Current OP41
Noise OP43
OP249
OP97
Require Ultrahigh Input Impedance OP80
OP97
OP41
OP43
Need Wider Bandwidth and High OP42
Speed OP43
OP249
AMP03
OP80EJ
LOAD
I
0I
0
= (E
1
– E
2
)/R
E
1
E
2
R
Figure 8. Differential Input Voltage-to-Current Converter
for Low I
OUT
. OP80EJ maintains 250 fA max input current,
allowing I
O
to be less than 1 pA.
AMP03
R2
R2
R1
–IN E
1
+IN E
2
A1
A2
E
0
OUTPUT
E
0
= (1 + 2R2 /R1) (E
2
– E
1
)
Figure 9. Suitable Instrumentation Amplifier Requirements
Can Be Addressed by Using an Input Stage Consisting of A1,
A2, R1, and R2. The following matrix suggests a suitable
amplifier.
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