A1468 Three-Wire, Differential Peak-Detecting IC

By Allegro MicroSystems, LLC 217

A1468 Three-Wire, Differential Peak-Detecting IC

Allegro Microsystems' A1468 is an 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. 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-magnet based speed, position, and timing applications, such as in speedometers.

  • 4.0 V to 26.5 V supply operating range
    • Can be used for 12 V and / or 5 V input systems
  • Running-mode calibration for continuous optimization
    • Maintain output accuracy during running mode after air-gap change
    • Calibration will complete when powered on during vibration
  • Precise duty-cycle signal throughout operating temperature range
    • Maintain accuracy over guaranteed temperature range
  •  Automatic gain control (AGC) for air-gap-independent switch points
    • Maintain output accuracy independent of power on airgap
  • Automatic offset adjustment (AOA) for signal-processing optimization
    • Maintain output accuracy independent of power on airgap
    • Remove offset induced by packaging
  • Minimum differential field 20 Gpk-pk
    • Large operational airgap

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