The A3212 integrated circuit is an ultra-sensitive, pole independent Hall-effect switch with a latched digital output. This sensor is especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palmtop computers. A 2.5 volt to 3.5 volt operation and a unique clocking scheme reduce the average operating power requirements to less than 15 µW with a 2.75 volt supply.

Unlike other Hall-effect switches, either a north or south pole of sufficient strength will turn the output on; in the absence of a magnetic field, the output is off. The polarity independence and minimal power requirement allow these devices to easily replace reed switches for superior reliability and ease of manufacturing, while eliminating the requirement for signal conditioning.

Improved stability is made possible through chopper stabilization (dynamic offset cancellation), which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress.

This device includes on a single silicon chip a Hall-voltage generator, small-signal amplifier, chopper stabilization, a latch, and a MOSFET output. Advanced BiCMOS processing is used to take advantage of low-voltage and low-power requirements, component matching, very low input-offset errors, and small component geometries.

Four package styles provide magnetically optimized solutions for most applications. Miniature low-profile surface-mount package types EH and EL (0.75 and 0.50 mm nominal height) are leadless, LH is a leaded low-profile SMD, and UA is a three-lead SIP for through-hole mounting. Each package is available in a lead (Pb) free version (suffix, –T) with 100% matte tin plated leadframe. EL package for limited release, engineering samples available.