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Two-wire Hall-effect latch offers protection against high-voltage transients

Allegro MicroSystems has introduced the A1244, a two-wire Hall-effect latch that features on-chip transient protection and a zener clamp to protect against over-voltage conditions on the supply line. The latch, which is programmed to optimise the magnetic switch point accuracy, uses the patented high-frequency, four-phase, chopper-stabilisation technique. According to the company, this results in low noise on the output, less switch-point variation over temperature, and fast settling times. The low noise and switch-point drift are claimed to allow the latch to realise good switching accuracy.
The high-voltage transient protection allows the latch to survive the conditions specified in ISO 7637-2 and 40V load dump, says the company. The company’s advanced bipolar CMOS technology of wafer fabrication process is used to achieve magnetic stability over temperature and to eliminate the offset inherent in single-element devices when exposed to harsh application environments. The latch is suitable for automotive transmission position sensing and motor commutations applications. It is also offered with two supply-current options such as I1 from 5.0 to 6.9mA and I2 from 2.0 to 5.0mA.

The latch also allows to inherently gain diagnostic capabilities, because there is always current flowing at one of two specified levels, says the company. Any output current outside these two narrow ranges is a fault condition. It is available in LH-style, small outline transistor-23W, low-profile package for surface-mount applications and UA-style, transistor outline-92, three-lead, miniature single-inline package for through-hole mounting.