Three-Wire Differential Sensor Thwarts EMI

Allegro’s ATS668 optimized Hall-effect three-wire differential speed sensor integrated circuit (IC) and permanent magnet pellet combination integrates EMC protection components for true zero-speed digital gear tooth sensing. It is offered in a small single over-mold package that can be easily assembled and used in conjunction with a wide variety of gear tooth sensing applications. Designed for automotive transmission systems, the device incorporates a dual element Hall IC that switches in response to differential magnetic signals created by a ferromagnetic target. The IC contains a sophisticated compensating circuit designed to eliminate the detrimental effects of magnet and system offsets. Digital processing of the analog signal provides zero-speed performance independent of air gap and dynamic adaptation of device performance to the typical operating conditions found in automotive applications, i.e., vibration and runout. For more details and full specs, a datasheet is available. Allegro MicroSystems, Worcester, MA. 508-853-5000