True Zero Speed Miniature Differential Peak-

Detecting Gear Tooth Sensor

ATS645LSH

2

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

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

www.allegromicro.com

• Automatic Offset Adjustment (AOA)

• True zero-speed operation

• Undervoltage lockout

• Wide operating voltage range

• Defined power-on state

The integrated circuit incorporates a dual-element Hall effect sensor

as well as signal processing that switches the output state in response

to changes in the magnetic gradients created by ferrous gear teeth.

The circuitry contains a sophisticated digital circuit to eliminate

magnet and system offsets and to achieve true zero speed operation

(U.S. Patent 5,917,320).A-D and D-Aconverters are used to adjust

the device gain at power-on and to allow switching independent of

the breadth of the air gap.

The regulated current output is configured for two wire applications,

requiring one less wire for operation than do switches with the more

traditional open-collector output.The package is available in a lead

(Pb) free version, with 100% matte tin leadframe plating.

Part Number

ATS645LSHTN-I1-T

Yes

Tape and Reel 13-in. 800 pcs./reel

6.0 Low to 14.0 High mA

ATS645LSHTN-I2-T

Yes

Tape and Reel 13-in. 800 pcs./reel

7.0 Low to 14.0 High mA

a. Certain variants cited in this footnote are in production but have been determined to be LAST TIME BUY. This classification indicates that sale

of this device is currently restricted to existing customer applications. The device should not be purchased for new design applications because

obsolescence in the near future is probable. Samples are no longer available. Status change: October 31, 2006. Deadline for receipt of LAST

TIME BUY ORDERS: April 27, 2007. These variants include:

ATS645LSHTN-I1.

b.

Certain variants cited in this footnote are in production but have been determined to be NOT FOR NEW DESIGN. This

classification indicates that sale of this device is currently restricted to existing customer applications. The device should not be

purchased for new design applications because obsolescence in the near future is probable. Samples are no longer available.

Status change: May 1, 2006. These variants include: ATS645LSHTN-I2.

Features and Benefits (continued)

Description (continued)

Absolute Maximum Ratings

Characteristic

Symbol

Notes

Rating

Units

Supply Voltage

28

–

Reverse-Supply Voltage

–18

V

Operating Ambient Temperature

Range L

–40 to 150

ºC

Maximum Junction Temperature

165

ºC

Storage Temperature

–65 to 170

ºC

Terminal List

Name

Description

Number

VCC

Connects power supply to chip

1

NC

No connection

2

TEST

For Allegro use, float or tie to GND

3

GND

Ground terminal

4

2

4

3

1

Pin-out Diagram