Allegro - A119x Hall-effect Unipolar switches w/capacitors

The A119x and A119x-F comprise a family of two-wire,
unipolar, Hall-effect switches, which can be trimmed by the
user at end-of-line to optimize magnetic switchpoint accuracy
in the application. The latter (-F option) are temperature compensated
for use with ferrite magnets. These devices are
produced on the Allegro™ advanced BiCMOS wafer fabrication
process, which implements a patented high-frequency, 4-phase,
chopper stabilization technique. This technique achieves
magnetic stability over the full operating temperature range,
and eliminates offsets inherent in devices with a single Hall
element that are exposed to harsh application environments.