Allegro MicroSystems, Inc. has released two new temperature-stable and stress-resistant Hall-effect latches, especially suited for operation in consumer and industrial products. According to Allegro MicroSystems, better high-temperature performance is made possible through dynamic offset cancellation, which reduces the residual offset voltage normally caused by device package overmolding, temperature dependencies, and thermal stress. The two devices are identical except for their magnetic switchpoints.
Both devices include, on a single silicon chip, a voltage regulator, a Hall-voltage transducer, a small-signal amplifier, chopper stabilization, a Schmitt trigger, and a short-circuit protected open-collector output to sink up to 25 mA. A south polarity magnetic field of sufficient strength is required to turn the output on. A north polarity field of sufficient strength is necessary to turn the output off. An onboard regulator permits operation with supply voltages in the range of 4.2 to 24 volts with an operating temperature range of –40 °C to 125 °C.
Allegro’s A3290 and A3291 devices are available in a three-lead single in-line package (UA) and a SOT-23W surface mount package (LH). The A329xKLHLT-T is priced at $0.44 and the A329xKUA-T is priced at $0.46 both in quantities of 1,000.