A1220 Datasheet, PDF (1/13 Pages) Allegro MicroSystems – Chopper Stabilized Precision Hall Effect Latches

A1220, A1221, and A1222
Chopper Stabilized Precision Hall Effect Latches
Features and Benefits
▪ Symmetrical latch switchpoints
▪ Resistant to physical stress
▪ Superior temperature stability
▪ Output short-circuit protection
▪ Operation from unregulated supply down to 3 V
▪ Reverse battery protection
▪ Solid-state reliability
▪ Small package sizes
Packages:
3-pin SOT23W (suffix LH)
Not to scale
3-pin SIP (suffix UA)
Description
The A1220, A1221, and A1222 Hall-effect sensor ICs are
extremely temperature-stable and stress-resistant devices
especially suited for operation over extended temperature ranges
to 150°C. Superior high-temperature performance is made
possible through dynamic offset cancellation, which reduces the
residual offset voltage normally caused by device overmolding,
temperature dependencies, and thermal stress. Each device
includes on a single silicon chip a voltage regulator, Hall-voltage
generator, small-signal amplifier, chopper stabilization, Schmitt
trigger, and a short-circuit protected open-collector output to
sink up to 25 mA. A south pole of sufficient strength turns the
output on. A north pole of sufficient strength is necessary to
turn the output off.
An onboard regulator permits operation with supply voltages
of 3 to 24 V. The advantage of operating down to 3 V is that
the device can be used in 3-V applications or with additional
external resistance in series with the supply pin for greater
protection against high voltage transient events.
Two package styles provide magnetically optimized packages
for most applications. Package type LH is a modified 3-pin
SOT23W surface mount package while UA is a three-pin ultra-
mini SIP for through hole mounting. Both packages are lead
(Pb) free, with 100% matte tin plated leadframes.
Functional Block Diagram
VCC
Amp
Regulator
Low-Pass
Filter
To All Subcircuits
Control
Current Limit
VOUT
GND
A1220-DS, Rev. 8