3212
MICROPOWER, ULTRA-SENSITIVE
HALL-EFFECT SWITCH
Preliminary Information
(Subject to change without notice)
November 12, 2001
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
Package Suffix ‘LH’ Pinning
3
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.
V
DD
1
2
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.
The A3212Ex is rated for operation over a temperature range of -40°C to
85°C. The A3212Lx is rated for operation over a temperature range of -40°C to
150°C. Two package styles provide a magnetically optimized package for most
applications. Suffix ‘LH’ is a miniature low-profile surface-mount package
while suffix ‘UA’ is a three-lead ultra-mini-SIP for through-hole or surface
mounting.
Dwg. PH-016-1
Pinning is shown viewed from branded side.
ABSOLUTE MAXIMUM RATINGS
at T = +25°C
A
Supply Voltage, VDD ............................. 5 V
Magnetic Flux Density, B .......... Unlimited
Output Off Voltage, VOUT ..................... 5 V
Output Current, IOUT .......................... 1 mA
Junction Temperature, TJ ............... +170°C
FEATURES
■ Micropower Operation
■ Operation With North or South Pole
■ 2.5 V to 3.5 V Battery Operation
■ Chopper Stabilized
Superior Temperature Stability
Extremely Low Switch-Point Drift
Insensitive to Physical Stress
Operating Temperature Range, TA
Suffix ‘E’ .................... -40°C to +85°C
■ ESD Protected to 5 kV
■ Solid-State Reliability
Suffix ‘L’ .................. -40°C to +150°C
Storage Temperature Range,
■ Small Size
TS .............................. -65°C to +170°C
■ Easily Manufacturable With Magnet Pole Independence
Caution: These CMOS devices have input
static protection (Class 3) but are still
susceptible to damage if exposed to
extremely high static electrical charges.
Always order by complete part number: the prefix ‘A’ + the basic four-digit
part number + the suffix ‘E’ or ‘L’ to indicate operating temperature range + a
suffix to indicate package style, e.g., A3212ELH .