Micropower Ultra-Sensitive Hall-Effect Switches

A3214

8

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Applications. Allegro's pole-independent sensing technique

allows for operation with either a north pole or south pole

magnet orientation, enhancing the flexibility of the device in ap-

plication assembling. The technology provides the same output

polarity for either pole face.

It is strongly recommended that an external bypass capacitor

be connected (in close proximity to the Hall element) between

the supply and ground of the device to reduce both external

noise and noise generated by the chopper-stabilization technique.

This is especially true due to the relatively high impedance of

battery supplies.

The simplest form of magnet that will operate these devices

is a bar magnet with either pole near the branded surface of the

device. Many other methods of operation are possible. Exten-

sive applications information on magnets and Hall-effect devices

is also available in the Allegro application note 27701, or at

www.allegromicro.com

0

+B

0

-B

OUTPUT ON

OUTPUT ON

5 V

MAX

BOPS

BRPS

B OPN

BRPN

MAGNETIC FLUX

OUTPUT OFF

OUTPUT

VDD

VOUT

GND

0.1 μF

10 pF

SUPPLY

(3 V BATTERY)

50 k

Ω