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Melexis’ new MLX90427 position sensor for steer-by-wire vehicles

May 22, 2024

Melexis has added a new product, the MLX90427, to its magnetic position sensor portfolio. The product is designed specifically for embedded position sensor applications that require high levels of functional safety, such as steer-by-wire.

The MLX90427 offers customer stray field immunity and EMC robustness, and features an SPI output with four distinct modes. These include rotary, joystick, and rotary stray field with internal angle computation, as well as a mode for raw data output.

As the automotive market continues to prioritize the digitization of control systems to support vehicle electrification and advanced autonomous capabilities, the demands on sensors are changing. Position sensors, which are critical components in innovations like steer-by-wire systems, must demonstrate exceptional reliability, functional safety, and accuracy. The requirements for sensors in electric vehicles are even more stringent, requiring excellent EMC robustness and stray field immunity. At the same time, these solutions must be cost-effective and easy to integrate.

The MLX90427 leverages Melexis’ extensive experience in automotive Hall effect sensing and is specifically engineered to meet the current and future technical requirements of the automotive industry. The MLX90427 features the Triaxis hall magnetic sensing element, which is sensitive to three components of flux density (Bx, By, and Bz) applied to the IC. This allows for the accurate detection of any magnet movement in its vicinity. The product also includes an analog-to-digital converter (ADC), a robust digital signal processor (DSP) for sophisticated signal processing, and an output stage driver for SPI signal output.

The MLX90427 can transition seamlessly between four distinct operating modes, including a standard rotary mode with two performance ranges, a joystick mode for XYZ 3D position sensing applications, and a 360-degree stray field immune mode for continuous rotational feedback in noisy environments. This versatility allows the IC to be used in various applications within a vehicle, such as steering, gearbox shifting, and wider human-machine interfaces (HMIs) like infotainment control knobs. The MLX90427 is AEC-Q100 qualified (Grade 0) and supports ISO26262 ASIL C SEooC (safety element out of context) up to ASIL D system level integration.

The MLX90427 is designed for easy integration and features a high-speed full-duplex SPI output for communication with a master microcontroller and a 14-bit resolution output. It is compatible with 5V and 3V3 applications and operates at temperatures ranging from -40oC to 160oC. The product also includes built-in self-diagnostics for swift fault reporting, enhancing the safety of critical systems.

The MLX90427 is available in SOIC8 packaging from May 2024, with a dual die TSSOP16 (fully redundant) variant set to launch in Q4 of 2024.

“Melexis has a long-standing reputation as the leading provider of sensors for safety-critical automotive systems, especially in areas like steering wheel position feedback,” Karen Stinckens, Global Marketing Manager Position Sensors at Melexis. She continued, “The MLX90427 is built from our previous success and represents not just the next step in automotive position sensing, but also a viable proposition for wider applications thanks to its advanced functionality and price point”.