ATS643LSH

Features:

• 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
• AGC and reference adjust circuit
• True zero-speed operation
• Undervoltage lockout
• Wide operating voltage range
• Defined power-on state


Specifications

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


Description

The ATS643LSH 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 ATS643LSH 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 the device specifications even through large changes in air gap or temperature.

The regulated current output is configured for two-wire operation, offering inherent diagnostic information. This device ATS643LSH is ideal for obtaining speed and duty cycle information in gear-tooth based applications such as transmission speed sensing.