Ultra-sensitive dual-channel quadrature Hall-effect bipolar switch

The A1230 is a highly sensitive, temperature-stable magnetic sensing device incorporating two Hall-effect sensing elements spaced 1 mm apart, each providing a separate digital output for speed and direction signal processing. The digital outputs are out of phase so that the outputs are in quadrature when interfaced with the proper ring-magnet design, allowing easy processing of the speed and direction signals.



The two Hall elements are photolithographically aligned to better than 1 µm: an accuracy which has not previously been achieved in fine-pitch detection applications. Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. The Allegro(R) patented, high-frequency chopper-stabilisation technique cancels offsets in each channel, providing 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 within the IC. As a result, the A1230 achieves industry-leading digital output jitter performance that is critical in high-performance motor commutation applications.



An on-chip low dropout (LDO) regulator allows the A1230 to be used over a wide operating voltage range. Post-assembly factory programming at Allegro provides sensitive switchpoints that are symmetrical between the two switches.



The A1230 features integrated electrostatic discharge protection between outputs and supply voltage to ground, a robust structure for EMC protection, and reverse battery protection on supply and both output pins.



The A1230 is available in a plastic 8-pin SOIC surface-mount package (L) and a plastic 4-pin SIP (K). Both are available in a temperature range of -40°C to +150°C. Each package is lead (Pb) free, with 100% matt tin-plated leadframe.