AC-coupled differential gear-tooth sensor

The MLX90254 is an AC-coupled differential gear-tooth sensor which targets automotive crankshaft applications. It is designed to be used with a back bias magnet to sense the rotating speed (incremental position) of a ferrous toothwheel. Alternatively, the MLX90254 can also be used to sense the rotating speed of a magnetic encoder.

The AC-coupling is realized through an on-chip capacitor implementing a high-pass filter. This filter prevents a zero-speed operation but it enables a continuous-time operation (no sampling) and consequently a high sensitivity (low hysteresis) and repeatability (jitter).

Its low hysteresis enables it to operate over a wide range of airgap and a broad temperature range (from -40°C to 150°C).

The device has an open-drain output (low-side) which is short-circuit protected.