3D technology-based position sensor with redundancy for safety-critical applications

TDK Corporation has expanded its Micronas direct-angle Hall-effect sensor family with the HAR 3927. This product employs proprietary 3D HAL pixel-cell technology and meets the demand for ISO 26262-compliant development. The new sensor comes with ratiometric analog output and a digital SENT interface according to SAE J2716 rev. 4.

The device provides a fully redundant sensor solution for safety-critical automotive applications, including linear-movement measurements in dual-clutch transmissions, engine stroke sensors, rotary position measurements in gear selectors and accelerator pedals, and electronic throttle control.

Each sensor comprises two stacked dies that function independently. The dies have minimal displacement and are penetrated by the same field lines. Compared to other solutions with two dies side by side, the sensor works with significantly smaller magnets. Its magnetic field amplitude range is 20mT to 130mT and down to 5mT with decreased accuracy.

The device is offered in a small eight-pin SOIC8 package. The redundant single-package solution decreases system costs while increasing the system's reliability due to smaller PCBs and fewer solder joints.

The sensor provides two different output formats and a linearisation block for an output signal of up to 33 setpoints (17 variable or 33 fixed setpoints). Due to the proprietary 3D HAL pixel-cell technology, clients can measure magnetic-field components, allowing linear and rotary position measurements up to 360 degrees and on-and-off-axis measurements. Primary characteristics such as gain and offset, reference position, etc., may be adjusted to the magnetic circuitry by programming the non-volatile memory.

Various configuration options of the device increase clients' flexibility throughout development and allow one sensor to be employed in multiple applications, which lessens costs and effort for re-qualification.