ATS643LSH Datasheet, PDF (1/16 Pages) Allegro MicroSystems – Self-Calibrating, Zero-Speed Differential Gear Tooth Sensor with Continuous Update

ATS643LSH
Package SH, 4-pin SIP
1234
1. VCC
2. No connection (float or tie to VCC)
3. Test pin (float or tie to GND)
4. GND
Self-Calibrating, Zero-Speed Differential
Gear Tooth Sensor with Continuous Update
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 compen-
sating 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 the device specifications even through large changes in air gap
or temperature.
The regulated current output is configured for two-wire operation, offering inher-
ent diagnostic information. This device is ideal for obtaining speed and duty cycle
information in gear-tooth based applications such as transmission speed sensing.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V_CC ..................See Power Derating
Reverse-Supply Voltage, V_RCC ........................ –18 V
Operating Temperature
Ambient, T_A................................ –40ºC to 150ºC
Maximum Junction, T_J(max)........................165ºC
Storage Temperature, T_S .................. –65ºC to 170ºC
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 through-
out temperature range
• Large operating air gaps
• <2 ms power-on time
• AGC and reference adjust circuit
• True zero-speed operation
• Undervoltage lockout
• Wide operating voltage range
• Defined power-on state
ATS643-DS, Rev. 1
Use the following complete part numbers when ordering:
Part Number
ATS643LSH-I1
Package
4-pin plastic SIP
I_CC Typical
6.0 Low to 14.0 High mA
ATS643LSH-I2
4-pin plastic SIP
7.0 Low to 14.0 High mA
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com