Description

The ATS617 gear-tooth sensor IC is a peak-detecting device

that uses automatic gain control and an integrated capacitor to

provide extremely accurate gear edge detection down to low

operating speeds. Each device consists of a high-temperature

plastic shell that holds together a samarium-cobalt pellet, a pole

piece, and a differential open-collector Hall IC that has been

optimized to the magnetic circuit. This small package can be

easily assembled and used in conjunction with a wide variety

of gear shapes and sizes.

The technology used for this device is Hall-effect based. The

device incorporates a dual-element Hall IC that switches

in response to differential magnetic signals created by

ferromagnetic targets. The sophisticated processing circuitry

contains an A-to-D converter that self-calibrates (normalizes)

the internal gain of the device to minimize the effect of air gap

variations. The patented peak-detecting filter circuit provides

immunity to magnet and system offsets and has the ability to

discriminate relatively fast changes such as those caused by tilt,

gear wobble, and eccentricities.This easy-to-integrate solution

provides first falling edge detection and stable operation to

extremely low rpm. The ATS617 can be used as a replacement

for the ATS616.

The ATS617 is ideal for use in systems that gather speed,

position, and timing information using gear-tooth-based

ATS617LSG-DS, Rev. 1

Features and Benefits

▪ Self-calibrating for tight timing accuracy

▪ First-tooth detection

▪ Immunity to air gap variation and system offsets

▪ Immunity to signature tooth offsets

▪ Integrated capacitor provides analog peak and

valley information

▪ Low timing-accuracy drift with temperature changes

▪ Low radiated emissions

▪ Integrated, series resistor on VCC pin for improved

transient immunity

▪ Large air gap capability

▪ Small, integrated package

▪ Optimized magnetic circuit

▪ Undervoltage lockout (UVLO)

▪ Wide operating voltage range

Dynamic, Self-Calibrating, Peak-Detecting, Differential

Hall Effect Gear Tooth Sensor IC

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Package: 4-pin SIP (suffix SG)

Not to scale

ATS617LSG

GND

VOUT

VC

C

Voltage

Regulator

TEST

Hall

Amp

Reference

Generator

Gain

Current

Limit

(Recommended)

Hall

Amp

Track and

Hold

Track and

Hold

UVLO

Power-On

Logic

Tooth and Valley

Comparator

Functional Block Diagram