Magnetic position sensor: ASIL-ready for demanding automotive applications

Melexis has announced a next-generation monolithic magnetic position sensor family, consisting of the MLX90371 and MLX90372, which provides robust absolute position sensing for automotive applications including powertrain actuators, pedals, and gear shifters.

Both new devices consist of a Triaxis Hall magnetic front end, an analogue to digital signal conditioner, a DSP for advanced signal processing and an output stage driver. Due to the Integrated Magneto Concentrator (IMC) they are sensitive to magnetic flux in three planes (X, Y & Z).

This facilitates the decoding of the absolute rotary or linear position of any moving magnet, enabling the design of non-contact position sensors.

The MLX90371 offers analogue or PWM output while the MLX90372 offers SENT (SAE J2716 rev Apr 2016) or PWM output.

A key feature of both parts is the robustness against stray fields that are increasingly present due to the electrification of modern vehicles, especially EV and HEV.

Measuring a magnetic field gradient

By measuring a magnetic field gradient, the device is intrinsically insensitive to stray fields up to 4kA/m (or 5mT), which are the levels required by many major automotive manufacturers.

Their ability to operate with a reduced magnetic field means that smaller and lower-cost magnets can also be used – ideal for space- and cost-constrained automotive applications.

The MLX90372 device includes an additional input pin that makes it possible to fully integrate other sensors (such as temperature, pressure, or switch inputs) allowing for the additional signal to be transmitted over the SENT output, reducing wire harness size and complexity.

Commenting on the release, Nick Czarnecki, Marketing Manager – Position and Speed Sensors at Melexis, said: “We are excited to be launching this next-generation family that builds upon our long history of magnetic sensing and patented Triaxis technology. The automotive business is striving to meet new challenges and the performance enhancements of our new offering will significantly contribute to key advancements.

“The ISO26262 ASIL-C capability of the MLX90372 and ASIL-B capability of the MLX90371 further ensures it is suitable for safety-critical automotive applications.”

The MLX90371 and MLX90372 are available in several versions for rotary and linear motion sensing and are a drop-in replacement for the MLX90364, MLX90365, MLX90366  and MLX90367, thereby bringing performance enhancements to earlier designs.

A PCB-less dual mould package (DMP) is available for integration directly into an assembly without requiring a printed circuit board.