Upgrade for direct-angle sensor family for functional safety applications

TDK Corporation has upgraded its Micronas 3D HAL direct-angle Hall-effect sensor family, HAL 37xy (HAL 37xy, HAR 37xy and HAC 37xy), for automotive and industrial applications concerning functional safety aspects. All members of HAL 37xy are now described as SEooC (Safety Element out of Context) ASIL B-ready, according to ISO 26262. The device rotary position detection features are employed in accelerator pedals, electronic throttle controls, rotary shifters (with push-function) and rear-axis steering systems. Moreover, the sensors detect the linear position in applications such as clutch or brake pedals, transmission systems, cylinders and valve position sensing.

The company enabled vertical Hall plates to combine into the standard CMOS process through its 3D HAL technology. The process made it simpler to evaluate the relative strength of the horizontal and vertical magnetic field components, which is essential for great angular performance. Compared, conventional planar Hall technology is only sensitive to the magnetic field orthogonal to the chip surface. It offers three different direct-angle sensor variants with the sensors: the proven sensor family, a version with redundancy function via two integrated Hall sensor dies (HAR 37xy), and a version with integrated capacitors (HAC 37xy).

This robust direct angle sensor family provides exceptional temperature stability, high resistance against air gap variations and magnet ageing, a variety of diagnostic functions and extremely effective protection circuitry. HAR 37xy, the dual-die version of the family, offers full redundancy from two independent dies stacked in a single package bonded on separate sides. The stacked-die architecture assures that both dies occupy the same magnetic-field position, therefore, generating synchronous measurement outputs. Redundant sensor solutions in a single package lessen system costs while increasing the reliability of the system by smaller PCBs and fewer solder joints. HAC 37xy combines a chip from the sensor family and two capacitors up to 330nF in a three-lead TO package for an ESD immunity of up to 8kV. The pins of the package may be welded or soldered straight to a lead frame removing the requirement for a PCB and decreasing the total system size and cost.

The ASIL-B upgrade enables the company’s sensor customers to utilise this product family in applications with functional safety demands.