Two-Wire Self-Calibrating Differential Speed and Direction Sensor with Vibration Immunity

ATS651LSH

2

651LSH-DS, Rev. 3

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

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

Functional Block Diagram

Current

Output

Adjust

GND

VCC

0.01μF

C

BYPASS

V+

Voltage

Regulator

TESTA

TESTB

Hall

Amp

PDAC

NDAC

Reference

Generator

and

Updates

and

Updates

PThresh

NThresh

Threshold

Logic

(Recommended)

(Recommended)

Speed

and

Direction

Logic

AGC

Offset

Adjust

Hall

Amp

PDAC

NDAC

Reference

Generator

PThresh

NThresh

Threshold

Logic

AGC

Offset

Adjust

Channel A

Hall

Element 1

Hall

Element 2

Hall

Element 3

Channel B

Typical Application Diagram

2

ATS651

1

3

4

0.01

μF

100

Ω

ECU

I

R

SENSE

C

SENSE

C

BYPASS

Note: Pins 2 and 3 may be connected to pin 4.