Allegro MicroSystems, LLC has announced a new package option for their A115x (A1152, A1153, A1156, and A1157) family of two-wire, unipolar, Hall-effect switches, which are factory-trimmed to optimize magnetic switchpoint accuracy. These devices are produced on the Allegro advanced BiCMOS wafer fabrication process, which utilizes 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. This package option eliminates the need for an external capacitor and the associated PCB, saving size, component-count, assembly cost and significantly simplifying the design process.
Allegro’s A115x family was developed for use in automotive and industrial applications that value safety or involve long sensor wiring harness. These include seat track position sensing, seat belt buckle presence, hood/trunk latching, and shift selector position sensing. Two-wire switches are particularly advantageous in cost- and/or weight-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 due to the fact that there is always output current flowing in either of two narrow ranges. A 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 surface-mount applications. The UA is a 3-pin, ultra-mini, single inline package (SIP) for through-hole mounting. The UB is a 2-pin, ultra-mini, single inline package (SIP) with an integrated capacitor for through-hole mounting or welding directly to connector pins, eliminating the PCB entirely. All three packages are RoHS-compliant, with 100 percent matte tin leadframe plating.
The A115x (A1152, A1153, A1156, and A1157) family of two-wire, unipolar, Hall-effect switches is available with a choice of magnetic switch-points, output current, output polarity, and package.
