AG920-07E NVE, AG920-07E Datasheet - Page 130

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

Specifications of AG920-07E

• Sensor Type: Magnetic. GMR (Giant Magnetoresistive)
• Interface: Analog
• Embedded: No
• Utilized Ic / Part: ABL & AKL Series GT Sensors
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Sensitivity: -
• Sensing Range: -
• Other names: 391-1063

Application Notes
In most currency detection applications, the signal from the bill is so small that it requires AC coupling
the sensor to a high gain low noise amplifier in order to get usable signal levels.
In order to achieve the highest possible signal, NVE’s most sensitive sensors are necessary. NVE’s
AA002-02, AAH002-02, and AAL002-02 sensors are recommended. These parts utilize large flux
concentrators for high sensitivity. These flux concentrators also contribute to the magnetic hysteresis
of the sensor. The hysteresis shows up mainly in a changing DC offset of the part. By AC coupling the
output of the sensor, the changes in magnetic field are seen at the output rather than the DC offset.
Another feature of AC coupling is a consistent output independent of the sensor’s orientation with
respect to the earth’s field. The device is sensitive enough to pick up the earth’s DC field. By AC
coupling, the DC offset contributed by the earth’s field, is not seen at the output.
Bipolar output signals are often very useful in currency detection and other magnetic media detection
applications. As a result, NVE recommends biasing the sensors in these applications by using a current
strap under the sensor to carry a bias current, and therefore bias the sensor higher, on its magnetic
operating characteristic.
Magnetic media detection and validation is an important and fast-growing application for magnetic
sensors. NVE’s sensors provide a reliable, non-contact, static or dynamic detection of the magnetic ink
on paper currency. NVE’s AA002 sensor can resolve the distinct features printed on U.S. and other
currency. NVE’s magnetic field sensors have been used for counterfeit detection, sorting, and simple
bill presence detection.
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