Allegro's A17301 integrates a single IC and EMC components into a small SIP package to provide a robust and cost-effective solution for digital ring-magnet sensing or ferromagnetic target sensing when coupled with a back-biasing magnet. The device can be utilized in two-wheeled vehicle applications where a wide variety of target shapes and sizes are used. The A17301 is ideally suited to obtain speed and duty cycle information for position and timing applications, such as in speedometers/tachometers.

The integrated circuit incorporates dual Hall-effect elements with 2.2 mm spacing and signal processing that switches in response to differential magnetic signals created by ring-magnet poles. The circuitry contains a sophisticated digital circuit to reduce system offsets, calibrate the gain for air-gap-independent switch points, and achieve true zero-speed operation. Running mode recalibration provides immunity to environmental effects such as micro-oscillations of the target or sudden air gap changes. Use of a digital peak detector for output switching control ensures the part is robust to input signal changes, regardless of the amount of signal shift between output edges.

The APS11700/760 family of micropower Hall-effect switches adds automatic power management to Allegro’s APS11000/060 family of Hall-effect switches, enabling average supply current as low as 6 µA. They are rugged enough for operation from batteries or unregulated supplies in harsh automotive and industrial environments. The power management happens in the background and is transparent to the host system, making them a drop-in upgrade for existing Hall-effect switches or a solid-state replacement for mechanical microswitches or reed switches. The APS11760 devices feature a vertical Hall-effect sensing element that is sensitive to magnetic flux parallel to the face of the IC package, mimicking the in-plane sensitivity of common reed switches.

These ICs are qualified to AEC-Q100 Grade 0 and compliant with ISO 26262 ASIL A. They can tolerate up to 40 V and junction temperature up to 165°C. In addition, they are internally protected against over-voltage, reverse-battery, load-dump, output short-circuits, human-body-model ESD up to ±11 kV, and other common automotive EMC conditions.