A new magnetoresistance (GMR) speed sensor—aimed at hybrid and pure electric vehicle (EV) transmissions—claims to offer an air gap that’s 50% larger than existing options. That, in turn, optimizes vibration performance and makes design safe and fuel-efficient. Allegro MicroSystems is also targeting the ATS19480 speed sensor IC at two-wheelers, off-road vehicles, and industrial designs requiring speed-only information.

Magnetic speed sensors are commonly used in automotive applications such as speedometers, ABS, camshafts, crankshafts, and automatic transmissions. These sensors either use a ferromagnetic gear tooth or encoder structure to measure linear or rotational speed and position.

The speed sensor measures the rotation of ferromagnetic gears. Source: Allegro MicroSystems

Allegro’s new GMR gear tooth speed sensor also leverages automotive-grade algorithms to ensure highly accurate speed detection. Here, signal compensation eliminates flatline conditions caused by system dynamics, and differential sensing protects against common-mode stray fields.

The GMR solution for gear tooth sensing comes integrated with ASIL B diagnostics and a certified safety design process for optional fault reporting. That enables robust operation under harsh operating conditions, which in turn, reduces failure rates, customer returns and warranty service claims.

The ATS19480 sensor IC is housed in a three-pin single inline package (SIP) along with magnet and EMC protection. Here, precision assembly optimizes IC-to-magnet positioning, which reduces tolerance stack between the IC and magnet and thus increases sensor accuracy and leaves ample margin for in-application installation tolerance.

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