A1140/41/42/43

A1140-DS

Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

ABSOLUTE MAXIMUM RATINGS

Magnetic Flux Density, B .........................Unlimited

Operating Temperature

On-chip protection

Supply transient protection

Reverse-battery protection

On-board voltage regulator

3.5 V to 24 V operation

Sensitive Two-Wire Chopper-Stabilized

Unipolar Hall-Effect Switches

Package LH, 3-pin SOT

Features and Benefits

1. VCC

2. No connection

3. GND

The A1140, A1141, A1142, and A1143 devices are sensitive, two-wire, unipo-

lar, Hall effect switches that are factory-programmed at end-of-line to optimize

magnetic switchpoint accuracy. These devices are produced on the Allegro

MicroSystems advanced BiCMOS wafer fabrication process, which implements a

patented, high-frequency, chopper-stabilization technique that achieves magnetic

stability and eliminates the offsets that are inherent in single-element devices

exposed to harsh application environments. Commonly found in a number of

automotive applications, the A1140-43 family of devices are utilized to sense: seat

track position, seat belt buckle presence, hood/trunk latching, and shift selector

position.

Two-wire unipolar switches are particularly advantageous in price-sensitive appli-

cations, because they require one less wire than the more traditional open-collec-

tor output switches. Additionally, the system designer gains inherent diagnostics

because output current normally flows in either of two narrowly-specified ranges.

Any output current level outside of these two ranges is a fault condition. The

A1140-43 family of devices also features on-chip transient protection, and a Zener

clamp to protect against overvoltage conditions on the supply line.

when there is no significant magnetic field present. The A1140 and A1142 have

All family members are offered in two package styles: SOT-23W, a miniature low-

profile package for surface-mount applications (suffix –LH), and TO-92, three-

lead ultra-mini Single Inline Package (SIP) for through-hole mounting

(suffix –UA).

Field-programmable versions are also available. Refer to: A1180, A1181, A1182,

and A1183.

NC

1

2

3

PTCT

1

2

3

1. VCC

2. GND

3. GND

Package UA, 3-pin SIP

Chopper stabilization

Low switchpoint drift over operating tem-

perature range

Low stress sensitivity

Factory programmed at end-of-line for

optimized switchpoints