Allegro MicroSystems Europe has introduced unipolar, Hall-effect switches that offer better performance than earlier devices and a greater variety of packaging options. They include a version with lead-free plating.

The A110x range, produced with BiCMOS technology, is intended to replace Allegro's A314x and A312x ranges of unipolar Hall-effect switches and includes five devices (A1101/02/03/04/06) with fast power-on time and low noise operation, Allegro claims. All devices in the family are identical except for magnetic switch points.

Device programming is performed after packaging to improve switch-point accuracy by eliminating offsets that can be induced by package

stress. Hall-element geometries and low-offset amplifiers help to minimise noise and reduce the residual offset voltage normally caused by device overmoulding, temperature excursions and thermal stress.

Each device incorporates, on a single silicon chip, a voltage regulator, Hall-voltage generator, small-signal amplifier, Schmitt trigger and NMOS output transistor. The integrated voltage regulator permits operation from 3.8 to 24V.

On-board protection circuitry enables a ±30V absolute maximum voltage rating, which provides better protection in automotive and industrial motor commutation applications without the addition of external components.