A1250_16 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Hall-Effect Latch / Bipolar Switch

A1250
Hall-Effect Latch / Bipolar Switch
FEATURES AND BENEFITS
• AEC-Q100 automotive qualified
• High-speed, 4-phase chopper stabilization
• Low operating voltage down to 3 V
• High sensitivity
• Stable switchpoints
• Robust EMC
Packages:
3-Pin SOT23W
(suffix LH)
3-Pin SIP
(suffix UA)
Not to scale
V+
VCC
Regulator
DESCRIPTION
The A1250 Hall-effect sensor IC is a temperature-stable,
stress-resistant bipolar switch. This device is the most sensitive
Hall-effect device in the Allegro™ bipolar switch family and is
intended for ring-magnet sensing. Superior high-temperature
performance is made possible through an Allegro patented
dynamic offset cancellation that utilizes chopper stabilization.
This method reduces the offset voltage normally caused by
device overmolding, temperature dependencies, and thermal
stress.
The A1250 includes the following 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. Advanced BiCMOS
wafer fabrication processing takes advantage of low-voltage
requirements, component matching, very low input-offset
errors, and small component geometries.
The A1250 Hall-effect bipolar switch turns on in a south
polarity magnetic field of sufficient strength and switches
off in a north polarity magnetic field of sufficient strength.
Because the output state is not defined if the magnetic field
is diminished or removed, to ensure that the device switches,
Allegro recommends using magnets of both polarities and of
sufficient strength in the application.
The A1250 is rated for operation in the ambient temperature
Continued on the next page…
To All Subcircuits
A1250-DS, Rev. 4
Clock / Logic
Amp
Low-Pass
Filter
Control
Current
Limit
Functional Block Diagram
VOUT
1Ω
GND