A3250_06 Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Field-Programmable, Chopper-Stabilized Unipolar Hall-Effect Switches

A3250 and A3251
Field-Programmable, Chopper-Stabilized
Unipolar Hall-Effect Switches
Features and Benefits
▪ Chopper stabilization for stable switchpoints throughout
operating temperature range
▪ Externally programmable operate point (through VCC
pin)
▪ On-board voltage regulator for 4.2 V to 24 V operation
▪ On-chip protection against:
▫ Supply transients
▫ Output short-circuits
▫ Reverse-battery condition
Package: 3 pin SOT89 (suffix LT) and
3 pin SIP (suffix UA)
Description
The A3250 and A3251 are field-programmable, chopper-
stabilized, unipolar Hall-effect switches designed for use in
high-temperature applications. These devices use a chop-
per-stabilization technique to eliminate offset inherent in
single-element devices.
The A3250 and A3251 are externally programmable
devices. The devices have a wide range of programmabil-
ity of the magnetic operate point (B_OP) while the hysteresis
remains fixed. This advanced feature allows for optimiza-
tion of the sensor switchpoint and can drastically reduce
the effects of variations found in a production environment,
such as magnet and device placement tolerances.
These devices provide on-chip transient protection. A Zener
clamp on the power supply protects against overvoltage
conditions on the supply line. These devices also include
short-circuit protection on the output.
The output of the A3250 switches LOW when subjected
to a south-polarity magnetic field with a flux density that
exceeds the threshold for B_OP, and switches HIGH when the
Not to scale
VCC
Continued on the next page…
Functional Block Diagram
Program/Lock
Programming
Logic
Offset Adjust
Regulator
Amp
Low-Pass
Filter
Current Limit
VOUT
GND
3250-DS Rev. 3