By Allegro MicroSystems, LLC 73
Allegro's A115x family of devices are the next generation of two-wire, unipolar, Hall-effect switches; factory trimmed to optimize the accuracy of the magnetic switch points. These devices employ a patented, high frequency, four-phase, chopper-stabilization technique to achieve magnetic stability over temperature and to eliminate offset inherent in single-element devices, when exposed to harsh automotive environments. Additionally, this advanced chopping technique provides significantly reduced jitter and faster power-on time.
Commonly found in a number of automotive applications, the A1152/3/5/6 devices are utilized to sense: seat track position, seat belt buckle presence, hood/trunk latching, steering lock position, and in shift selectors. Two-wire, unipolar switches require one less wire for operation versus the more traditional open-collector output switches. Additionally, the user gains diagnostics, as there is always current at one of two specified levels. Any output current outside of these two narrow ranges is a fault condition.