ATS672LSB

30Dec03, Rev. 1.42

Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

Allegro MicroSystems, Inc.

1

2

3

4

1. VCC

2. VOUT

3. Test pin (tie to GND)

4. GND

ABSOLUTE MAXIMUM RATINGS

Operating Temperature

• Tight timing accuracy throughout

temperature range

• True zero-speed operation

• Air gap-independent switch points

• Large operating air gaps

• Operation down to 3.3 V

• Digital output representing target

profiles

The ATS672 true zero-speed gear tooth sensors provide manufacturer-friendly

solutions for digital gear tooth sensing applications, through an optimized con-

figuration of Hall-effect IC and magnet, packaged together in a single SIP (Single

In Line Package) module. The SIP consists of an overmolded enclosure, which

encapsulates a samarium cobalt magnet, a pole piece, and a true zero-speed Hall-

effect IC that has been optimized to the magnetic circuit. This package can be

easily assembled and used in conjunction with gears of various shapes and sizes.

The ATS672 sensor incorporates a single-element Hall-effect IC that switches in

response to the magnetic signal created by a ferrous target (the gear). The IC con-

tains a sophisticated digital circuit designed to eliminate the detrimental effects of

magnet and system offsets. Signal processing is used to provide zero-speed perfor-

mance, independent of air gap, and also to dynamically adapt device performance to

the typical operating conditions found in automotive applications, such as reducing

sensitivity to vibration. High resolution (9 bit) peak-detecting DACs are used to set

the adaptive switching thresholds of the device. Hysteresis in the thresholds reduces

the negative effects of any anomalies in the magnetic signal (such as magnetic

overshoot) associated with the targets used in many automotive applications. The

ATS672 also includes a low-bandwidth filter that increases the noise immunity and

the signal-to-noise ratio of the sensor. These features result in potential improve-

ments in both the timing accuracy and the jitter performance of the device.

The ATS672LSB version is optimized for gear tooth sensing applications. The

ATS672LSB-LT is optimized for cam sensing.

Self-Calibrating Gear Tooth Sensor with 9-Bit Signal Capture

Use the following complete part numbers when ordering:

Part Number

Package

Application

ATS672LSB

4-pin plastic SIP

Gear tooth sensing

ATS672LSB-LT

4-pin plastic SIP

Cam sensing

Package SB, 4-pin SIP

Features and Benefits

• Single-chip solution for high reliability

• Small mechanical dimensions

• Optimized Hall-effect IC/magnetic

systems

• AGC and reference-adjust circuits

• Undervoltage lockout