AATS643LSH_06 Datasheet, PDF (1/16 Pages) Allegro MicroSystems – Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous Update

ATS643LSH
Self-Calibrating, Zero-Speed Differential
Gear Tooth Sensor with Continuous Update
Features and Benefits
▪ Fully-optimized differential digital gear tooth sensor
▪ Single chip-IC for high reliability
▪ Internal current regulator for 2-wire operation
▪ Small mechanical size (8 mm diameter x 5.5 mm depth)
▪ Switchpoints air gap independent
▪ Digital output representing gear profile
▪ Precise duty cycle accuracy throughout temperature
range
▪ Large operating air gaps
▪ <2 ms power-on time
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Packages: 4 pin SIP (suffix SH)
Description
The ATS643 is an optimized combination of integrated circuit
and magnet that provides a manufacturer-friendly solution
for true zero-speed digital gear-tooth sensing in two-wire
applications. The device consists of a single-shot molded
plastic package that includes a samarium cobalt magnet, a
pole piece, and a Hall-effect IC that has been optimized to the
magnetic circuit and the automotive environment. This small
package can be easily assembled and used in conjunction with
a wide variety of gear shapes and sizes.
The integrated circuit incorporates a dual element Hall-effect
sensor with signal processing circuitry that switches in response
to differential magnetic signals created by rotating ferrous
targets. The device contains a sophisticated compensating
circuit to eliminate magnet and system offsets immediately
at power-on. Digital tracking of the analog signal is used
to achieve true zero-speed operation, while also setting the
device switchpoints. The resulting switchpoints are air gap
independent, greatly improving output and duty cycle accuracy.
The device also uses a continuous update algorithm to fine-
tune the switchpoints while in running mode, maintaining
Not to scale
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Functional Block Diagram
Hall AMP
Offset Adjust
AGC
PDAC
NDAC
ThresholdP
Reference
Generator
and Updates
ThresholdN
Internal
Regulator
Threshold
Logic
VCC (Pin 1)
GND (Pin 4)
ATS643-DS, Rev. 2