New sensor for steer-by-wire released

Melexis has added the MLX90427 to its magnetic position sensor portfolio. The product is tailored for embedded position sensor applications requiring high functional safety levels. Next to offering customer stray field immunity and EMC robustness, the cost-effective MLX90427 features an SPI output with four distinct modes. It includes a rotary, joystick, and rotary stray field with internal angle computation alongside one mode for raw data output. It is ideal for steer-by-wire applications.

With the automotive market increasingly emphasising the digitisation of control systems to aid vehicle electrification and advanced autonomous capabilities, the demands placed on sensors are evolving. For innovations such as steer-by-wire systems, where there is no mechanical linkage between the steering wheel and steering rack, position sensors are a critical component that must display exceptional reliability, functional safety, and accuracy. The demands for sensors in EVs are heightened, necessitating outstanding EMC robustness and stray field immunity. Simultaneously, solutions must be cost-effective and simple to integrate.

The device is the company's next-generation magnetic position-sensing IC. Drawing upon its extensive automotive Hall effect sensing expertise, this product has been specifically engineered to satisfy the automotive industry's current and future technical requirements. At the core of the device is the Triaxis hall magnetic sensing element, which exhibits sensitivity to three components of flux density (Bx, By, and Bz) applied to the IC, allowing for the accurate detection of movement of any magnet in its vicinity. This is supported by an ADC, a robust DSP for sophisticated signal processing, and an output stage driver for SPI signal output.

The device can uniquely transition seamlessly between four distinct operating modes. These modes include a standard rotary mode with two performance ranges, a joystick mode for XYZ 3D position sensing applications, and the 360° stray field immune mode for continuous rotational feedback in noisy environments. Within a vehicle, this allows the IC to be utilised in various applications, such as steering, gearbox shifting, and wider HMIs like infotainment control knobs, thereby streamlining vehicle design procedures. Featuring AEC-Q100 qualification (Grade 0), the device is inherently reliable and is an ISO26262 ASIL C SEooC supporting up to ASIL D system-level integration. In safety-critical applications like steering columns, the MLX90427, with its excellent stray field immunity and EMC robustness, can be deployed alongside sensors using differing sensing technologies, such as the inductive sensing MLX90513, to attain the highest levels of functional safety through heterogeneous redundancy.

The device is designed for embedded position sensor applications and features a high-speed full-duplex SPI output for communication with a master microcontroller and a 14-bit resolution output. Allowing for simple system integration, the device is 5V and 3V3 application compatible and features a wide operating temperature of -40C to 160C. The implementation of built-in self-diagnostics ensures swift fault reporting, which enhances the safety of critical systems.

Backed by the company's extensive application and functional safety knowledge, the device is a robust and cost-effective solution. Its high accuracy and multifunction operation are ideal for the next generation of vehicle control systems.

"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," stated 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."