A3211

The A 3211 and A3212 integrated circuits are ultra-sensitive, pole in de pen dent Hall-effect switches with latched digital output. These sensors are es pe cial ly suited for operation in battery-operated, hand-held equip ment such as cellular and cordless tele phones, pagers, and palmtop com put ers. A 2.5 volt to 3.5 volt operation and a unique clocking scheme reduce the average op er at ing power requirements to less than 15 W with a 2.75 volt supply.

Unlike other Hall-effect switches, either a north or south pole of suf fi cient strength will turn the output on in the A3212, and in the absence of a magnetic field, the output is off. The A3211 provides an inverted output. The polarity independence and minimal power requirements 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 de pen den cies, and thermal stress.

This device includes on a single silicon chip a Hall-voltage generator, small-signal amplifier, chopper sta bi li za tion, a latch, and a MOSFET output. Ad vanced 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 op ti mized solutions for most ap pli - ca tions. 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 mount ing. Packages are available in lead (Pb) free versions (suffix, T) with 100% matte tin plated leadframe. EL package for limited release, engineering samples available.