Low-jitter dual-channel Hall-effect direction detection sensor IC

February 12, 2013 // By Julien Happich
The A1233 from Allegro MicroSystems Europe is a dual-channel, Hall-effect direction detection sensor IC that provides digital output signals indicating the speed and direction of a rotating target.

The A1233 is a highly sensitive, temperature-stable magnetic sensing device ideal for use in ring-magnet based speed and direction systems in harsh
automotive and industrial environments. A key feature of the device is the fact that the Hall sensing elements are photolithographically aligned to better than 1 µm. This accurate mechanical location between the two active Hall elements eliminates the major manufacturing hurdle commonly encountered in fine-pitch detection applications.

The A1233 is a monolithic device containing two independent Hall-effect bipolar switches located 1.63 mm apart. It provides excellent speed and direction information for small-geometry targets. Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. A patented high-frequency chopper-stabilisation technique cancels offsets in each channel and provides stable operation over the full specified temperature and voltage ranges. The high-frequency chopping circuits also allow an increased analogue signal-to-noise ratio at the input of the digital comparators in the IC for very low digital output jitter.

An on-chip low dropout (LDO) regulator allows the A1233 to be used over a wide operating voltage range. Post-assembly factory programming at Allegro provides sensitive switch-points that are symmetrical between the two switches. The A1233 comes in a plastic 8-pin SOIC surface mount package (L) and a plastic 4-pin single-inline package (K). Both versions are available for a temperature range from -40°C to +150°C. Each package is lead (Pb) free, with 100% matt tin-plated leadframe.

Visit Allegro MicroSystems Europe at www.allegromicro.com