2D Hall-effect speed and direction sensor ICs for magnetic encorders

The APS12625 features speed and direction outputs whereas the APS12626 has quadrature (Channel A and B) outputs. An 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 IC contains a pair of sensor ICs that are orthogonal to one another and provide 90° of phase separation between channels that is 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.

“Allegro’s vertical Hall technology enables sensor ICs that are uniquely suited to magnetic motor/encoder applications,” explained Jim Judkins, Product Line Director for Digital Position Sensor ICs at Allegro MicroSystems. 

Judkins continued: “Designers can achieve lower BOM cost and power in less board area while meeting their safety goals and spending less time iterating designs to support changes in magnet pitch or system form-factor.”

These monolithic devices each include three Hall plates (one planar, two vertical), a multiplexer, a small-signal amplifier, chopper stabilisation, a Schmitt trigger, and two NMOS output transistors. They operate from 2.8-5.5V 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.