ATS694LSM: Crankshaft Position Sensor IC With Speed and Direction Output


The ATS694LSM is a combined Hall-effect sensing integrated circuit, back-biasing rare-earth pellet, and EMC protection circuit that provides a user-friendly, PCB-less solution for true zero-speed digital crankshaft sensing. The ATS694 provides speed and direction information through a variable pulse-widthoutput protocol. The device can be used to sense rotating ferromagnetic targets.

Three Hall plates are used to create two differential channels. These channels, along with advanced direction detection algorithms, are used to produce a highly accurate speed output. The combination of high accuracy with direction information provides absolute position on most crank targets even in cases of engine backlash, making it ideal for stop/start engine designs.

Advanced calibration techniques are used to optimize signal offset and amplitude. This calibration, combined with the digital tracking of the signal, results in accurate switchpoints across the full range of air gap and operating temperature. The open-drain output provides a voltage output such that the time between falling electrical edges (period) corresponds to the speed, and the time between a falling edge and corresponding rising edge (pulse width) indicates direction.

The ATS694 is provided in a 3-pin SIP package that is lead (Pb) free, with matte-tin leadframe plating and integrated discrete EMC protection components.

Top Features

  • Allegro SM package with integrated EMC components provides robustness to most automotive EMC requirements
  • Integrated back-biasing rare-earth pellet
  • Digital output with speed and direction information provides ferromagnetic target position information
  • Enhanced algorithms provide low jitter and high output accuracy performance
  • Electrical offset compensation through chopper stabilization
  • Dual zero-crossing with internal hysteresis
  • Highly repeatable across operating temperature range
  • Automatic Gain Control and Automatic Offset Adjust circuits result in air-gap-independent switchpoints
  • Robust test coverage capability using Scan Path and IDDQ measurement
  • Factory-programmable options for application-specific performance optimization

Typical Applications

  • Crankshaft

Part Number Specifications and Availability

Part Number Package Type Temperature RoHS
Part Composition /
RoHS Data
Comments Samples Check Stock
ATS694LSM-RNOBD-T 3-lead SIP -40°C to 150°C -- View Data New 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.


ATS694 Packages

Application Notes

Crank Sensor IC for Stop-Start