AH422, unipolar Hall effect switch, designed with Bipolar technology, is south sensitive unipolar Hall Effective switch and includes on-chip Hall element voltage generator, a voltage regulator for operation with supply voltages of 3.8 to 40V, temperature compensation circuitry, small-signal amplifier, Schmitt trigger and an open-collector output. The sensor is designed to respond to South poles. While the magnetic flux density(B) is larger than operate point Bop, the output will be turned on with low output level. Then the output is held until the magnetic flux (B) is lower than release point Brp. The output will be turned off with high output level. AH422 offers a variety of packages, including TO-92, SOT-23. All packages are RoHS compliant.