Dual Output Differential Speed and Direction Sensor IC

ATS17501

13

Allegro MicroSystems

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

FUNCTIONAL DESCRIPTION

General

The ATS17501 sensor module contains a single-chip, dual differ-

ential Hall-effect sensor IC, a rare-earth pellet, and a flat ferrous

pole piece (concentrator). As shown in Figure 6, the Hall-effect

sensor IC supports three Hall elements that sense the magnetic

profile of the ferrous gear target simultaneously but at different

points (each channel spaced at 1.75 mm pitch), generating two

differential internal signals processed for precise switching of the

digital output signals. Direction of rotation can be determined

based on the phase relationship of the two differential internal

signals. The ATS17501 is intended for use with ferromagnetic

targets.

The Hall-effect sensor IC is self-calibrating and possesses a tem-

perature-compensated amplifier as well as a full-range analog-

to-digital converter (ADC). This allows for accurate processing

of a wide range of target magnetic profile amplitudes and offsets.

The on-chip voltage regulator provides supply noise rejection

throughout the operating voltage range. Changes in temperature

do not greatly affect the ATS17501 due to the stable amplifier

design and full-range ADC. The Hall elements and signal pro-

cessing electronics are integrated on the same silicon substrate.

The ATS17501 is capable of providing digital information that

is representative of the mechanical features of a rotating target

gear. Figure 6 shows the automatic translation of the mechanical

profile to the digital output signal. No additional optimization is

needed, and minimum processing circuitry is required. This ease

of use reduces design time and incremental assembly costs for

most applications.

Device Orientation to Target

(Pin 4 Side)

(Pin 1 Side)

IC

Right Channel

Left Channel

Package Case

Branded Face

(Bottom View of

Package Case)

Channel

Element Pitch

Right Channel

Left Channel

Left Channel

Right Channel

Mechanical Position (Target moves past device pin 4 to pin 1)

Target

(Gear)

This tooth

sensed earlier

This tooth

sensed later

IC

F3

F2

F1

South Pole

North Pole

+B

Target

(Gear)

Target Magnetic Profile

Output Option: Speed Output Protocol

Figure 6: Magnetic Profile

Advance Information Datasheet

Subject to Change Without Notice

March 19, 2020