A3211 Datasheet, PDF (1/13 Pages) Allegro MicroSystems – Micropower, Ultra-sensitive Hall-effect Switches

A3211 and A3212
Micropower, Ultrasensitive
Hall-Effect Switches
Features and Benefits
▪ 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
Packages:
DFN (EH)
DFN (EL)
Description
The A 3211 and A3212 integrated circuits are ultrasensitive,
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 W
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
residual offset voltage normally caused by device overmolding,
temperature dependencies, and thermal stress.
SOT23W (LH)
Not to scale
SUPPLY
SIP (UA)
Continued on the next page…
Functional Block Diagram
SWITCH
X
TIMING
LOGIC
OUTPUT
GROUND
3211-DS, Rev. 16
Dwg. FH-020-5