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Hall-effect speed/direction sensor IC with hysteresis detection

Hall-effect speed/direction sensor IC with hysteresis detection

10 February 2015

Improved overall accuracy when sensing high-resolution, multi-pole ring magnets

Allegro MicroSystems: The new A1232 from Allegro MicroSystems Europe is a Hall-effect speed and direction sensor IC with built-in hysteresis detection.

The A1232 is a highly sensitive temperature-stable magnetic sensing device that is ideal for use in ring magnet based speed and direction sensing systems in harsh automotive and industrial environments.

It is 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.

This new magnetic sensor IC is targeted at motor applications in the automotive market. Key applications include window lifts, sunroofs, sliding doors and tail/trunk lift gates. It is also suitable for non-automotive applications such as garage door openers and window blinds.

The A1232LLETR-T is available in an 8-pin TSSOP (suffix LE) surface mount package.

About Allegro
Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide. Further information about Allegro can be found at

Allegro MicroSystems Europe, headquartered in Chertsey, United Kingdom, is the European sales and marketing operation, and operates a network of representatives and distributors throughout Europe.  Allegro also has an engineering design centre in Edinburgh in Scotland and an application and marketing centre in Annecy in France.

  • Allegro MicroSystems, LLC
    115 Northeast Cutoff
    Worcester, MA 01606
    United States / America
    Tel.: +1-508-854-5359
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