Speed/direction Hall sensor IC detects hysteresis

February 13, 2015 // By Julien Happich
The A1232 from Allegro MicroSystems Europe is a Hall-effect speed and direction sensor IC with built-in hysteresis detection.

The highly sensitive temperature-stable magnetic sensing device can be used in ring magnet based speed and direction sensing systems in harsh automotive and industrial environments. It is claimed to be the first device of its kind with the ability to detect when it powers up in the magnetic hysteresis band. This feature reduces angle accuracy error, which can occur when edges are missed at start-up.

The Allegro A1232 includes dual Hall elements spaced 1.63 mm apart that are photolithographically aligned to within 1 µm. The precise spacing of the sensing elements eliminates a major manufacturing hurdle encountered when using fine-pitch ring magnets. The signals from the dual Hall elements are encoded into logic outputs representing the speed and direction of the target.

Factory trimming and Allegro's proprietary chopper stabilisation and dynamic offset cancellation techniques provide precise, symmetrical magnetic switchpoints over a wide range of operating conditions. A built-in voltage regulator, short-circuit protected outputs, internal zener clamps, reverse battery protection, and a -40̊ to +150̊C operating range give the A1232 the ruggedness demanded by automotive applications. The A1232LLETR-T comes in an 8-pin TSSOP (suffix LE) surface mount package.

Visit Allegro MicroSystems at www.allegromicro.com