Datasheet

®
INA111
11
FIGURE 12. Voltage Controlled Current Source.FIGURE 11. AC-Coupled Instrumentation Amplifier.
FIGURE 13. Shield Driver Circuit.
FIGURE 14. Multiplexed-Input Data Acquisition System.
INA111
R
G
V
O
C
1
0.1µF
OPA602
Ref
R
1
1MΩ
f
–3dB
=
1
2πR
1
C
1
= 1.59Hz
V
IN
+
–
INA111
V
IN
+
–
V
IN
+
–
Channel 8
Channel 1
MPC800
MUX
ADS574
+5V
12 Bits
Out
R
G
Ref
INA111
OPA177
C
1
50nF
R
G
R
2
R
G
Make G ≤ 10 where G = 1 +
50k
Load
V
IN
G
•
R
2
I
L
=
R
1
10kΩ
V
IN
Ref
INA111
V
IN
–
V
IN
+
OPA602
511Ω
22.1kΩ
22.1kΩ
Ref
V
O
For G = 100
R
G
= 511Ω // 2(22.1kΩ)
effective R
G
= 505Ω
100Ω
NOTE: Driving the shield minimizes CMR degradation
due to unequally distributed capacitance on the input
line. The shield is driven at approximately 1V below
the common-mode input voltage.