A1120_16 Datasheet, PDF (1/18 Pages) Allegro MicroSystems – Chopper-Stabilized Precision Hall-Effect Switches

A1120, A1121, A1122, A1123, and A1125
Chopper-Stabilized Precision Hall-Effect Switches
FEATURES AND BENEFITS
▪ AEC-Q100 automotive qualified
▪ Unipolar switchpoints
▪ Resistant to physical stress
▪ Superior temperature stability
▪ Output short-circuit protection
▪ Operation from unregulated supply
▪ Reverse-battery protection
▪ Solid-state reliability
▪ Small package sizes
Packages:
3-pin SOT23W
(suffix LH)
Not to scale
(A1120)
(A1121, A1122,
A1123, and A1125)
3-pin SIP (suffix UA)
DESCRIPTION
The A1120, A1121, A1122, A1123, and A1125 Hall-effect
unipolar switches are extremely temperature-stable and
stress-resistant sensor ICs, 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-drain output to sink up to 25 mA.
An on-board 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.
For the A1120, A1121, A1122, and A1123, a south pole of
sufficient strength turns the output on. Removal of the magnetic
field turns the output off. The A1125 is complementary, in that
for these devices, a south pole turns the A1125 output off, and
removal of the magnetic field turns the output on.
Two package styles provide a magnetically optimized package
for most applications. Package type LH is a modified SOT23W,
surface-mount package, while UA is a three-lead ultra-mini
SIP for through-hole mounting. Each package type is lead
(Pb) free (suffix, –T), with a 100% matte-tin-plated leadframe.
Functional Block Diagram
VCC
Amp
Regulator
Low-Pass
Filter
To All Subcircuits
Control
Current Limit
VOUT
GND
A1120-DS, Rev. 16