A1242-I2

The A1242 Hall effect latch is a two-wire latch especially suited for operation over extended temperature ranges, from –40 to +150°C. Superior high-temperature performance is made possible through the Allegro® patented dynamic offset cancellation technique, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress.

The current-switching output technique allows for the reduction in cost in the wiring harness because only two connections to the sensor are required. The current- switching output structure also inherently provides more immunity against EMC/ESD transients. These sensors have low magnetic thresholds, thereby enabling more flexibility in the magnetic circuit design.

The Hall effect latch will be in the high output current state in the presence of a magnetic South Pole field of sufficient magnitude and will remain in this state until a sufficient North Pole field is present.

The A1242 includes the following on a single silicon chip: a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger, and a current source output. Advanced BiCMOS wafer fabrication processing takes advantage of low-voltage requirements, component matching, very low input-offset errors and small component geometries.

Suffix ‘L-’ devices are rated for operation over a temperature range of –40°C to +150°C; suffix ‘E-’ devices are rated for operation over a temperature range of –40°C to +85°C. Two A1242 package styles provide magnetically optimized solutions for most applications. Package LH is a SOT23W, a miniature low-profile surface-mount package, while package UA is a three-lead ultra-mini SIP for through-hole mounting. Each package is available lead (Pb) free, with 100% matte tin plated leadframes.