DFN (EH)

TheA3211andA3212integratedcircuitsareultrasensitive,pole

independent Hall-effect switches with latched digital output.

These devices are especially suited for operation in battery-

operated, hand-held equipment such as cellular and cordless

telephones, pagers, and palmtop computers. A 2.5 to 3.5 V

operation and a unique clocking scheme reduce the average

operating power requirements to less than 15 μW with a

2.75 V supply.

Unlike other Hall-effect switches, either a north or south pole

of sufficient 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

residualoffsetvoltagenormallycausedbydeviceovermolding,

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 CMOS processing

is used to take advantage of low-voltage and low-power

3211-DS, Rev. 22

• AEC-Q100 automotive qualified

• Micropower operation

• Operation with north or south pole

• 2.5 to 3.5 V battery operation

• Chopper stabilized

□ Superior temperature stability

□ Extremely low switchpoint drift

□ Insensitive to physical stress

• High ESD protection

• Solid-state reliability

• Small size

• Easily manufacturable with magnet pole independence

Micropower, Ultrasensitive

Hall-Effect Switches

Packages:

Functional Block Diagram

Not to scale

A3211 and A3212

DFN (EL)

SOT23W (LH)

SIP (UA)

TIMING

LOGIC

Dwg. FH-020-5

GROUND

OUTPUT

SUPPLY

X

SWITCH

FEATURES AND BENEFITS

DESCRIPTION

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