A1126LUA-T Datasheet, PDF (1/14 Pages) Allegro MicroSystems – Chopper Stabilized Omnipolar Hall-Effect Switch

A1126
Chopper Stabilized Omnipolar Hall-Effect Switch
Features and Benefits
• Omnipolar operation
• Low switchpoint drift
• Superior temperature stability
• Insensitive to physical stress
• Reverse battery protection
• Robust EMC capability
• Robust ESD protection
Packages:
3-pin SOT23-W
2 mm × 3 mm × 1 mm
(suffix LH)
3-pin ultramini SIP
1.5 mm × 4 mm × 3 mm
(suffix UA)
Not to scale
Approximate footprint
Description
The A1126 integrated circuit is an omnipolar, ultrasensitive
Hall-effect switch with a digital output. This device has an
integrated regulator permitting operation to 24 V.
This device is especially suited for operation through extended
temperature ranges, up to 150°C. Superior high-temperature
performance is made possible through an Allegro^® patented
dynamic offset cancellation, which reduces the residual offset
voltage normally caused by device overmolding, temperature
excursions, and thermal stress.
The A1126 Hall-effect switch includes the following on a
single silicon chip: voltage regulator, Hall-voltage generator,
small-signal amplifier, chopper stabilization, Schmitt trigger,
and a short circuit protected open-drain output. Advanced
BiCMOS wafer fabrication processing is used to take advantage
of low-voltage requirements, component matching, very low
input-offset errors, and small component geometries.
The omnipolar operation of the A1126 allows activation with
either a north or a south polarity field of sufficient strength.
In the absence of a magnetic field, the output is off. This
patented magnetic-polarity–independence feature makes
this device an excellent replacement for reed switches, with
improved ease of manufacturing, because the A1126 does not
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Functional Block Diagram
VCC
Regulator
To all subcircuits
Amplifier
Signal
Recovery
Omnipolar
Switchpoints
Control
Current
Limit
VOUT
GND
A1126-DS