AG920-07 NVE, AG920-07 Datasheet - Page 104

• Manufacturer Part Number: AG920-07
• Description: KIT EVALUATION GT SENSOR
• Manufacturer: NVE

Specifications of AG920-07

• Sensor Type: Magnetic. GMR (Giant Magnetoresistive)
• Interface: Analog
• Embedded: No
• Utilized Ic / Part: ABL & AKL Series GT Sensors
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Supply: -
• Sensitivity: -
• Sensing Range: -
• Other names: 391-1022

Threshold Detection Circuit
The figure below shows the implementation of a low power threshold detection circuit that utilizes the
AAxxx-02 GMR Magnetic Field Sensor and the Burr Brown INA118 instrumentation amplifier.
Comparator hysteresis has been added around the LM311 comparator to minimize random triggering
of the circuit on potential noise sources and pickup. The gain of the instrumentation amplifier is the
same as before. The hysteresis of the comparator is approximately:
V
h
≈
2.5



R
1
8 Vin+
4 Vin-
+
R
R
+5V
2
1
+
C1 0.1uF
R
1 Vout-
5 Vout+
3
www.nve.com
−
R
T
1
R
HRESHOLD
RG
+
2
+2.5V
R
2



Vref
phone: [phone] fax: [phone]
R1
3 IN+
1 RG1
2 IN-
8 RG2
5 REF
R2
Neglecting the finite output swing of the comparator.
D
- 104 -
INA118/BB
3 -
2 +
ETECTION
+5V
7
4
U2
-5 V
U3 IM311
C2 0.1uF
+5V
6
4 V-
8 V+
C3 0.1uF
1 G
C
7
IRCUIT
Application Notes
R3
Vout