The A1688 is a Hall-effect based integrated circuit (IC) that
provides a user-friendly solution for true zero-speed digital ring
magnet and gear tooth sensing in two-wire applications. The
A1688 is offered in the UB package, which integrates the IC
and a high temperature ceramic capacitor in a single overmolded
SIP package. The integrated capacitor provides enhanced EMC
performance with reduced external components.
The integrated circuit incorporates a dual-element Hall-effect
circuit and signal processing that switches in response to
differential magnetic signals created by magnetic encoders, or,
when properly backbiased with a magnet, from ferromagnetic
targets. The device contains a sophisticated digital circuit that
reduces magnet and system offsets, calibrates the gain for air
gap independent switchpoints, and provides true zero-speed
operation.
Signal optimization occurs at power-up through the combination
of offset and gain-adjust and is maintained throughout operation
with the use of a running-mode calibration scheme. Runningmode
calibration provides immunity from environmental effects
such as micro-oscillations of the sensed target or sudden air
gap changes.
The regulated current output is configured for two-wire interface
circuitry and is ideally suited for obtaining speed information in
wheel speed applications. The Hall element spacing is optimized
for high resolution, small diameter targets. The package is lead
(Pb) free, with 100% matte-tin leadframe plating.
