AG911-07 NVE, AG911-07 Datasheet - Page 101

• Manufacturer Part Number: AG911-07
• Description: KIT EVALUATION GMR SWITCH
• Manufacturer: NVE

Specifications of AG911-07

• Sensor Type: Magnetic. GMR (Giant Magnetoresistive)
• Interface: Analog
• Embedded: No
• Utilized Ic / Part: AD Series Switches
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Supply: -
• Sensitivity: -
• Sensing Range: -
• Other names: 391-1021

Two Op Amp Bridge Amplifier
The two op amp circuit shown below reduces the loading of the preamplifier on the NVE bridge
outputs but still has a CMRR that is dependent on the ratio of resistor matching. The AC CMRR is also
poor in that any delay of the common mode signal through op amp U2 provides a mismatch in the
signals being delivered to op amp U3 for cancellation. Its advantages are simplicity and low cost.
The equation for DC gain of the two op amp circuit (assuming infinite input impedance of the op
amps) is:
Vout
=
V
ref
8 Vin+
4 Vin-
+
V
+5V
IN



Vref
1
C1 0.1uF
5 Vout+
1 Vout-
+
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


R
R
T
R4
2
1
WO

 +

3 +
2 -
O



LMC7101A/NS
P
2R
R
A
G
+5V
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2
U2
MP



7 V+
4 V-
R3



C2 0.1uF
P
RG
- 101 -
REAMPLIFIER
for
6



R
R
R1
2
1

 =

3 +
2 -



C
R
R
LMC7101A/NS
IRCUIT
4
3
Application Notes

 and V

+5V
U3
R2
7 V+
4 V-
C3 0.1uF
6
IN
= (V
out+
Vout
) - (V
out-
)