ATS643LSH Datasheet | Allegro MicroSystems

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 throughout temperature range - Large operating air gaps - <2 ms power-on time Description The ATS643 is an optimized bination 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 pensating 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 finetune the switchpoints while in running mode, maintaining Continued on the next page… Packages: 4 pin SIP (suffix SH) .. Continued on the next page… Not to scale Functional Block Diagram VCC (Pin 1) Hall AMP Offset Adjust Internal Regulator PDAC Threshold P Reference Generator and Updates Threshold N NDAC Threshold Logic GND (Pin 4) ATS643-DS, Rev. 2 Features and Benefits (continued) - AGC and reference adjust circuit - True...