ATS657LSH: Dynamic, Self-Calibrating, Threshold-Detecting, Differential Speed and Direction Hall-Effect Gear Tooth Sensor IC


This device is no longer in production. The device should not be purchased for new design applications. Samples are no longer available. Date of status change: December 1, 2015.

Recommended Substitutions: For existing customer transition, and for new customers or new applications, refer to the ATS692LSHTN-RSNPH-T.

The ATS657 includes an optimized Hall-effect sensing integrated circuit (IC) and rare earth pellet to create a user-friendly solution for direction detection and true zero-speed, digital gear tooth sensing in two-wire applications. The small package can be assembled simply and used in conjunction with a wide variety of gear tooth sensing applications.

The IC employs patented algorithms for the special operational requirements of automotive transmission applications. The speed and direction of the target are communicated by this two-wire device through a variable pulse width output protocol. The advanced vibration detection algorithm systematically calibrates the IC on the initial teeth of a true rotation signal and not on vibration, always guaranteeing an accurate signal in running mode. Even the high angular vibration caused by engine cranking is completely rejected by the device.

Patented running mode algorithms also protect against air gap changes whether or not the target is in motion. Advanced signal processing and innovative algorithms make the ATS657 an ideal solution for a wide range of speed and direction sensing needs.

The device package is lead (Pb) free, with 100% matte tin leadframe plating.

Top Features

  • Rotational direction detection
  • High start-up and running mode vibration immunity
  • Single-chip sensing IC for high reliability
  • Internal current regulator for two-wire operation
  • Variable pulse width output protocol
  • Automatic Gain Control (AGC) and offset adjust circuit
  • True zero-speed operation
  • Wide operating voltage range
  • Undervoltage lockout
  • ESD and reverse polarity protection

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
ATS657LSHTN-T 4-lead SIP -40°C to 150°C Yes View Data Discontinued Contact your
local sales rep
Distributor Stock

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm.


The ATS657 is supplied in a 4-pin SIP (suffix SH) package. The package is lead (Pb) free, with 100% matte tin lead frame plating.

SH SIP 4 pin