Three-wire true zero-speed magnetic speed sensor IC

June 29, 2016 // By Graham Prophet
This device’s surface mount package allows for ease of use for PCB applications, and has been designed to meet requests for a PCB mounted speed sensor IC featuring an advanced sensing algorithm. This device makes for compact ring magnet applications using PCB mounting, and is suitable for automotive transmissions and industrial equipment.

The A1667 incorporates a dual-element Hall IC that switches in response to differential magnetic signals created by a ring magnet. The IC contains a compensating circuit designed to eliminate the detrimental effects of magnet and system offsets. Digital processing of the analogue signal provides zero-speed performance independent of air gap as well as dynamic adaptation of device performance to the typical operating conditions found in automotive applications, including reduced vibration sensitivity. 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 the targets used in many automotive applications. The open-drain output is configured for three-wire applications. In addition to the 8-pin SOIC surface mount package (suffix L), the A1667 is also available in a 4-pin SIP through-hole package (suffix K).


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