Allegro MicroSystems, LLC announces a new optimized Hall-effect three-wire differential speed sensor integrated circuit (IC) and permanent magnet pellet combination. Allegro’s ATS668 has integrated EMC protection components to provide a user-friendly solution for true zero-speed digital gear tooth sensing. It is offered in a small single over-mold package that can be easily assembled and used in conjunction with a wide variety of gear tooth sensing applications. The ATS668 is designed for automotive transmission systems making it also ideal for non-automotive applications such as recreational vehicles, industrial equipment, white goods, and exercise equipment.

The device incorporates a dual element Hall IC that switches in response to differential magnetic signals created by a ferromagnetic target. The IC contains a sophisticated compensating circuit designed to eliminate the detrimental effects of magnet and system offsets. Digital processing of the analog signal provides zero-speed performance independent of air gap and dynamic adaptation of device performance to the typical operating conditions found in automotive applications (i.e. vibration and runout). High-resolution 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 associated with system or target anomalies typically seen in many automotive applications.

The fully integrated package and industry proven algorithm performance makes the ATS668LSM an ideal solution for a wide range of speed sensing needs. This device is available in a lead (Pb) free 3-pin SIP package (SM) with matte-tin leadframe plating.

Features & Benefits:

• Three-wire back-biased speed sensor optimized for transmission speed-sensing applications
• Integrated in-package EMC protection circuit allows compliance to most Automotive EMC environments without external circuitry
• Small-signal lockout for immunity to vibration
• Tight timing accuracy over full operating temperature range
• True zero-speed operation
• Air gap independent switchpoints
• Large operating air gaps achieved through use of gain and offset adjust circuitry
• Wide operating voltage range with undervoltage lockout (UVLO)
• Digital output representing target profile
• Single-chip sensing IC for high reliability
• High-speed startup

Please click here to download a copy of ATS668 Hall-effect three-wire differential speed sensor integrated circuit (IC) data sheet.