FEATURES AND BENEFITS

• Three-wire back-biased speed sensor optimized for

transmission speed-sensing applications

• Integrated in-package EMC protection circuit allows

compliance to most Automotive EMC environments

without external circuitry

• Small-signal lockout for immunity to vibration

• Tight timing accuracy over full operating temperature

range

• True zero-speed operation

• Air gap independent switchpoints

• Large operating air gaps achieved through use of gain

and offset adjust circuitry

• Wide operating voltage range with undervoltage lockout

(UVLO)

• Digital output representing target profile

• Single-chip sensing IC for high reliability

• High-speed startup

DESCRIPTION

TheATS668LSM is an optimized Hall-effect integrated circuit

(IC) and permanent magnet pellet combination with integrated

EMCprotectioncomponentstoprovideauser-friendlysolution

fortruezero-speeddigitalgeartoothsensing.Thesmallpackage

can be easily assembled and used in conjunction with a wide

variety of gear tooth sensing applications.

The device incorporates a dual element Hall IC that switches

in response to differential magnetic signals created by

a ferromagnetic target. The IC contains a sophisticated

compensating circuit designed to eliminate the detrimental

effects of magnet and system offsets. Digital processing of the

analogsignalprovideszero-speedperformanceindependentof

airgapandalsodynamicadaptationofdeviceperformancetothe

typical operating conditions found in automotive applications

(i.e.vibrationimmunityandrunouttolerance).High-resolution

peak detecting DACs are used to set the adaptive switching

thresholds of the device. Hysteresis in the thresholds reduces

the negative effects of any anomalies in the magnetic signal

associated with system or target anomalies typically seen in

many automotive applications.

This device is available in a lead (Pb) free 3-pin SIP package

(SM) with matte-tin leadframe plating.

ATS668LSM-DS, Rev. 2

True Zero-Speed High-Accuracy

Gear Tooth Sensor IC

PACKAGE: 3-pin SIP (suffix SM)

Functional Block Diagram

Not to scale

ATS668LSM

Package

Die

Hall Amp

Offset

Adjust

AGC

PDAC

NDAC

+

-

Control Logic and Threshold Generator

+

-

Output

Control

VCC

VOUT

GND

Threshold

Comparators

April 24, 2017