A3213 and A3214: Micropower, Ultrasensitive Hall-Effect Switches

The A3213 and A3214 integrated circuits are ultra-sensitive, pole independent Hall-effect switches with a latched digital output. They are especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palmtop computers. A 2.4 to 5.5V operation and a unique clocking scheme reduce the average operating power requirements – the A3213 to 825 µW, the A3214 to 14 µW (typical, at 2.75 V). Except for operating duty cycle and average operating current, the A3213 and A3214 are identical.

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 allows these devices to 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.

These devices include, 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.

Range 'E' devices are rated for operation over a temperature range of -40°C to 85°C; range 'L' devices are rated for operation over a temperature range of -40°C to 150°C. Two package styles provide a magnetically optimized package for most applications. 'LH' is a miniature low-profile surface-mount package, 'UA' is a three-lead SIP for through-hole mounting. For the A3213, a microleadless DFN/MLP package 'EL' also is available. Each package is available in a lead (Pb) free version (suffix, –T), with a 100% matte tin plated leadframe.