As the automotive market increasingly emphasizes the digitalization of control systems to facilitate vehicle electrification and advanced autonomous capabilities, the demands placed on sensors are evolving. In innovations such as power-by-wire systems, where there is no mechanical connection between the steering wheel and the steering rack, position sensors are an essential component that must offer exceptional reliability, functional safety, and accuracy. The requirements for sensors in electric vehicles are even more stringent, demanding excellent electromagnetic compatibility and immunity to stray fields. At the same time, solutions must be cost-effective and easy to integrate.
The MLX90427 is Melexis' next-generation magnetic position sensing IC. Leveraging Melexis' extensive experience in automotive Hall effect sensing, this product has been specifically designed to meet the current and future technical requirements of the automotive industry. At the heart of the MLX90427 is the Triaxis Hall magnetic sensing element, which exhibits sensitivity to three flux density components (Bx, By, and Bz) applied to the IC, enabling precise detection of the movement of any nearby magnet. It features an analog-to-digital converter (ADC), a robust digital signal processor (DSP) for sophisticated signal processing, and an output stage controller for SPI signal output.
Operation and safety
The MLX90427 has the unique ability to seamlessly switch between four distinct operating modes. These modes include a standard rotary mode with two performance ranges, a joystick mode for 3D XYZ position sensing applications, and a 360-degree spurious-field immune mode for continuous rotary feedback in noisy environments. Within a vehicle, this allows the IC to be used in a variety of applications, such as steering, gear shifting, and broader human-machine interfaces (HMIs) like infotainment control knobs, thereby streamlining vehicle design processes. With an AEC-Q100 (Grade 0) rating, the MLX90427 is intrinsically reliable and is an ASIL C ISO26262 SEooC (Safety Out of Context) that supports system-level integration up to ASIL D. In safety-critical applications, such as steering columns, the MLX90427, with its excellent spurious field immunity and EMC robustness, can be installed alongside sensors using different sensing technologies, such as the inductive sensing MLX90513, to achieve the highest levels of functional safety through heterogeneous redundancy.
Integration and Communication:
The MLX90427 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. For ease of system integration, the MLX90427 supports 5V and 3.3V applications and offers a wide operating temperature range from -40°C to 160°C. Integrated self-diagnostics ensure rapid fault notification, enhancing the safety of critical systems.
Backed by Melexis' extensive application and functional safety expertise, the MLX90427 is a robust and cost-effective solution. Its high accuracy and multifunction operation make it perfectly suited for the next generation of vehicle control systems.
“Melexis has a long-standing reputation as a leading supplier of sensors for safety-critical automotive systems, particularly in areas such as steering wheel position monitoring,” said Karen Stinckens, Global Marketing Director for Position Sensors at Melexis. She added, “The MLX90427 builds on our previous success and represents not only the next step in automotive position monitoring but also a viable proposition for broader applications thanks to its advanced functionality and price.”
The MLX90427 will be available in SOIC8 form factor starting in May, with a fully redundant dual-array TSSOP16 variant launching in Q4 2024.
