8

A3230-DS

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

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

Chopper-Stabilized Hall Effect Bipolar Switch

A3230

exhibiting negative switch behavior operate in a similar but

opposite manner. A north polarity field of sufficient strength,

back to the low state.

The A3230 is designed to attain a small hysteresis, and thereby

provide more sensitive switching. Although this means that

true latching behavior cannot be guaranteed in all cases, proper

switching can be ensured by use of both south and north mag-

netic fields, as in a ring magnet.

Bipolar devices adopt an indeterminate output state when

powered-on in the absence of a magnetic field or in a field that

lies within the hysteresis band of the device. The correct state is

For more information on Bipolar switches, refer to Application

Note 27705, Understanding Bipolar Hall Effect Sensors.

Applications

It is strongly recommended that an external bypass capacitor be

connected (in close proximity to the Hall sensor) between the

supply and ground of the device to reduce both external noise

and noise generated by the chopper stabilization technique. As is

shown in Panel B of figure 1, a 0.1µF capacitor is typical.

Extensive applications information on magnets and Hall-effect

sensors is available in:

• Hall-Effect IC Applications Guide, AN27701,

• Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead

Welding and Lead Forming, AN27703.1

• Soldering Methods for Allegro’s Products – SMT and Through-

Hole, AN26009

All are provided in Allegro Electronic Data Book, AMS-702 and

the Allegro Web site: www.allegromicro.com