Allegro MicroSystems, LLC introduces a new optimized Hall-effect sensing IC that provides a user-friendly solution for digital ring-magnet sensing, or when coupled with a magnet, ferromagnetic target sensing, in three-wire applications. The small device package can be easily assembled into applications for use in conjunction with a wide variety of target shapes and sizes. Allegro’s A1468 sensor IC is targeted at the automotive market and is designed and optimized for motor bike applications.
The integrated circuit incorporates dual Hall-effect elements with a 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, to calibrate the gain for air gap independent switch points, and to achieve true zero-speed operation through peak detecting algorithm. Signal optimization occurs at power-on through the combination of offset and gain adjust, and is maintained throughout the operating time with the use of a running-mode calibration.
The running-mode calibration provides immunity to environmental effects such as micro-oscillations of the target or sudden air gap changes. The device is ideally suited to obtaining speed and duty cycle information in ring-magnetbased speed, position, and timing applications, such as in speedometers. Allegro's A1468LK-T is available in a 4-pin through hole SIP package (suffix K) and is priced at $1.28 in quantities of 1,000.