Deemed revolutionary by its maker, the A1160 unipolar, Hall-effect switch integrates a coil surrounding the Hall sensing element. During normal operation, the device functions as a typical unipolar switch. However, when the diagnostics pin pulls high, it enters diagnostics mode. This allows current to pass through the coils, generating a 20G magnetic field. Proximity of the coils to the Hall sensing element allows the element to sense the field while ignoring external fields. In diagnostics mode the device outputs a PWM signal with a 50% duty cycle when the device is properly sensing the magnetic field. The A1160LLH-T comes in a five-lead SOT-23W package and pricing is $0.41 each/1,000. A datasheet is available at http://www.allegromicro.com/~/media/Files/Datasheets/A1160-Datasheet.ashx
Allegro MicroSystems, LLC
Worcester, MA
508-853-5000
http://www.allegromicro.com