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Quad Operational Amplifier Instrumentation Amplifier
3-10
Example Circuits
3.8
Quad Operational Amplifier Instrumentation Amplifier
Figure 3–7 shows area 300 equipped with a quad operational amplifier
configured as a quad-operational-amplifier instrumentation amplifier using a
dual power supply.
Basic setup is done by choice of input and feedback resistors. The transfer
function for the circuit as shown is:
V
OUT
+
ǒ
V
INB
*
V
INA
Ǔ
ǒ
R303
)
2(R302)
R303
Ǔ
)
R325
R309
Where:
R302 = R318, R309 = R316, and R325 = R329
A
V
+
ǒ
R303
)
2(R302)
R303
Ǔ
)
R325
R309
+
101 as shown
To cancel the effects of offset errors, adjust V
adj
(D304+) by applying an extra
signal.