A1190-2-3 and A1190-2-3-F: Programmable, Chopper-Stabilized, Two-Wire Hall-Effect Switches

Allegro MicroSystems recommends APS11900 for all new programmable Automotive 2-wire Hall-Effect switch IC designs.

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.

The A119x and A119x-F family has a number of automotive applications. These include sensing seat track position, seat belt buckle presence, hood/trunk latching, and shift selector position.

Two-wire unipolar switches are particularly advantageous in cost-sensitive applications because they require one less wire for operation versus the more traditional open-collector output switches. Additionally, the system designer inherently gains diagnostics because there is always output current flowing, which should be in either of two narrow ranges. Any current level not within these ranges indicates a fault condition.

All family members are offered in three package styles. The LH is a SOT-23W style, miniature, low-profile package for surfacemount applications. The UA is a 3-pin, ultra-mini, single inline package (SIP) for through-hole mounting. The UB is a 2-pin single inline package (SIP) for through-hole mounting that integrates the power supply decoupling capacitor. All three packages are lead (Pb) free, with 100% matte-tin leadframe plating.