High-accuracy magnetic position sensor for linear stroke

24-10-2023 | Melexis | Semiconductors

Melexis has expanded its MLX9042x series of 3D magnetic position sensing solutions with the MLX90423. This new device blends high accuracy for long strokes (up to 30mm), stray field immunity and ISO26262 (supports up to ASIL D system integration). This cost-effective solution is excellent for automotive ADAS applications with space constraints such as braking systems (brake rod).

Comprising the company's Triaxis Hall technology, the device is dedicated to linear displacement (absolute linear) up to 30mm where stray field rejection is needed. This is normally only feasible with advanced inductive technology. The device is a single-die ASIL C as per ISO 26262, while dual die option is also available to support up to ASIL D system integration. It also inherits the superior capabilities of other series members regarding absolute maximum ratings, EMC characteristics and improved accuracy over the full thermal range.

The device is a monolithic magnetic position processor IC. It comprises a Triaxis Hall-based magnetic front end, an analog to digital signal conditioner, a DSP for advanced signal processing and a programmable output stage driver. By sensing the three components of the magnetic flux density applied to the ICs (Bx, By and Bz), the device decodes the absolute position of a magnet moving linearly. This allows engineers to control applications such as brake rod travel, pedal position or park lock actuators, among others.

The device provides ratiometric analog output, PWM output or SENT frames encoded according to a Secure Sensor format. In accordance with ISO 11452-8, it is robust against magnetic stray field up to 5mT (4kA/m).

In common with other sensors of the MLX9042x series, it aims to ensure first-time-pass EMC testing, which keeps the design process efficient and the costs under control. High AMR, including reverse polarity, reduces the number of quality incidents due to electrical overstress and permits achieving various OEM needs.

All MLX9042x devices are created for operational temperatures up to 160C. All devices are fully AEC-Q100 qualified. They can be provided in SMD packages or SMP-3 PCB-less packages, combining the sensor and EMC capacitors in a single mould.

"The MLX90423 is a future-proof product which will serve ADAS, such as braking applications. Compared to other solutions for linear position sensing, it offers the best price-performance ratio," said Karen Stinckens, global marketing manager Position Sensors at Melexis.

By Seb Springall