The A1184 device is a standard, two-wire, unipolar, Hall effect switches. The operate point, BOP, can be field-programmed, after final packaging of the sensor and placement into the application. This advanced feature allows the optimization of the sensor switching performance, by effectively accounting for variations caused by mounting tolerances for the device and the target magnet.

This family of devices are produced on the Allegro MicroSystems advanced BiCMOS wafer fabrication process, which implements a patented, high-frequency, chopper-stabilization technique that achieves magnetic stability and eliminates the offsets that are inherent in single-element devices exposed to harsh application environments. Commonly found in a number of automotive applications, the A1184 is utilized to sense: seat track position, seat belt buckle presence, hood/trunk latching, and shift selector position.

Two-wire unipolar switches are particularly advantageous in price-sensitive applications, because they require one less wire than the more traditional open-collector output switches. Additionally, the system designer gains inherent diagnostics because output current normally flows in either of two narrowly-specified ranges. Any output current level outside of these two ranges is a fault condition. The A1184 also features on-chip transient protection, and a Zener clamp to protect against overvoltage conditions on the supply line.

The output current of the A1184 switches HIGH in the presence of a south polarity magnetic field of sufficient strength; and switches LOW otherwise, including when there is no significant magnetic field present.

Also see: A1180, A1181, A1182, A1183, A1185, and A1186.