2D Hall-effect sensor IC targets both motor and magnetic encorder applications

February 13, 2018 // By Christoph Hammerschmidt
Allegro MicroSystems Europe has released a new family of Hall-Effect Latch ICs that feature both vertical and planar Hall elements. The APS12625 and APS12626 sensor ICs enable reduced system size and bill-of-materials (BOM) cost along with an increase in performance and flexibility due to 2D sensing. They were developed in accordance with ISO 26262 and qualified per AEC-Q100, making them suitable for automotive and other safety systems.

The APS12625 features speed and direction outputs whereas the APS12626 has quadrature (Channel A and B) outputs. A unique, optional feature allows the host system to restore the previous state of the sensor after a power-cycle. This reduces the potential accumulation of lost counts in intelligent motion applications such as window lifts with anti-pinch requirements.  

Each of the two sensors contains a pair of sensor ICs that are orthogonal to one another and provide 90° of phase separation between channels independent of magnet pole spacing and air gap. They are both available in each of three combinations of vertical and planar Hall elements (XY, ZX, and ZY).  Virtually any orientation between the sensor IC and the ring magnet can be accommodated, and the ring magnet pitch can be changed without losing quadrature.

These monolithic devices each include three Hall plates (one planar, two vertical), a multiplexer, a small-signal amplifier, chopper stabilization, a Schmitt trigger, and two NMOS output transistors. They operate from 2.8 to 5.5 V and up to 175°C junction temperature. Each tiny SOT23-5 device replaces a pair of conventional Hall-effect latch ICs, meaning that redundant sensing for safety applications can be accomplished in virtually the same space as non-redundant implementations using legacy technology.