A1186

A1185 and A1186 Ultrasensitive Two-Wire Field-Programmable Chopper-Stabilized Unipolar Hall-Effect Switches The A1185 and A1186 are ultrasensitive, 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 new DABIC5 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 A1185 and A1186 devices are 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. This provides distinct current ranges for IOUT(H) and IOUT(L). Any output current level outside of these two ranges is a fault conditio...