The Honeywell Nanopower Series of magnetoresistive sensor ICs is sensitive enough to detect magnetic fields as weak as 7 Gauss while drawing only 360 nA with a 1.8V supply voltage. Pinout for the three-pin sensors are power, ground and output. The supply voltage is flexible and can handle from 1.65 to 5.5 VDC. In the presence of a magnetic field that trips the sensor, the output pin is near the supply voltage. In the absence of a magnetic field, the output pin is close to ground. The push-pull output stage does not require an external pull-up resistor.
Mouser Electronics Inc.