Allegro MicroSystems Europe has announced a new package option for their A119x/A119x-F (A1190, A1192, and A1193) family of two-wire, unipolar, Hall-effect switches, which can be trimmed by the user at end-of-line to optimise magnetic switch-point accuracy in the application. The A119x and A119x-F are produced on the Allegro™ advanced BiCMOS wafer fabrication process, which implements a patented high-frequency, 4-phase, chopper stabilisation 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 new package option eliminates the need for an external capacitor and the associated PCB, saving size, component-count, and assembly cost and significantly simplifying the design process. The latter (-F option) devices are temperature compensated for use with ferrite magnets.
The A119x and A119x-F family was developed for use in automotive and industrial applications that value safety or involve long sensor wiring harnesses. 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 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 lead (Pb) free, with 100% matt-tin leadframe plating.
The A119x/A119x-F two-wire, unipolar, Hall-effect switches are available with a choice of magnetic switch-points, output current, output polarity, and package. The A119x/A119x-F family complements Allegro’s A115x/A115x-F family of factory-programmed 2-wire unipolar switches; both families of products are form, fit, and function compatible.