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-

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

3250-DS Rev. 3

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

Field-Programmable, Chopper-Stabilized

Unipolar Hall-Effect Switches

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Package: 3 pin SOT89 (suffix LT) and

3 pin SIP (suffix UA)

Functional Block Diagram

Not to scale

A3250 and A3251

Current Limit

Amp

Regulator

Program/Lock

Low-Pass

Filter

VCC

GND

Programming

Logic

Offset Adjust

VOUT