Date: 02/06/2021

ASIL-B ready angle sensor to detect positions of clutch or brake pedals

To address the growing demand of position sensors in automotive market, TDK continue to improve its sensor of family for position sensing applications. TDK said it 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 regarding functional safety aspects. All members of HAL 37xy are now defined as SEooC (Safety Element out of Context) ASIL B-ready, according to ISO 26262. HAL 37xy rotary position detection features are used in applications such as accelerator pedals, electronic throttle controls, rotary shifters (with push-function) and rear-axis steering systems. The sensors can detect linear position in applications like clutch or brake pedals, transmission systems, cylinders and valve position sensing. The ASIL-B upgrade makes it fit for applications with functional safety demands.

TDK says it has enabled vertical Hall plates to integrate into the standard CMOS process through its 3D HAL technology to make it easier to evaluate relative strength of the horizontal and vertical magnetic field components, which is key for excellent angular performance. This is a lot better compared to conventional planar Hall technology where it is only sensitive to the magnetic field orthogonal to the chip surface. TDK is offering 3 different direct-angle sensor variants with the HAL 37xy sensors: the proven HAL 37xy sensor family, a version with redundancy function via two integrated Hall sensor dies (HAR 37xy), and a version with integrated capacitors (HAC 37xy).

The key features of HAL 37xy include robustness, high temperature stability, high resistance against air gap variations and magnet aging, a range of diagnostic functions and very effective protection circuitry.

TDK explains "HAR 37xy, the dual-die version of the HAL 37xy family, provides full redundancy from two independent dies stacked in a single package that are bonded on separate sides. The stacked-die architecture ensures that both dies occupy the same magnetic-field position, thus generating synchronous measurement outputs. Redundant sensor solutions in a single package reduce system costs while increasing the reliability of the system through smaller PCBs and less solder joints. HAC 37xy integrates a chip from the HAL 37xy sensor family and two capacitors up to 330 Nf in a three-lead TO package for an ESD immunity of up to 8 Kv. The pins of the package can be welded or soldered directly to a lead frame eliminating the need for a printed circuit board (PCB) and reducing the total system size and cost."

Key specifications, features and benefits of this product family:

Very low angular error of ±1.5° @ 30 Mt amplitude
End of shaft and off-axis 360° angular measurement
Direct measurement of magnetic field amplitude (BX, BY, BZ)
Family members with analog, PWM or SENT output
SEooC according to ISO 26262 (ASIL-B ready) to support functional safety applications
Suitable for automotive applications, thanks to a wide ambient temperature range from -40 °C up to max. 160 °C
Packages SOIC-8 and TO-92UF
Output formats Analog, PWM, SENT SAE J 2716
Flux density amplitude range 20 Mt… 100 Mt. Down to 10 Mt with reduced accuracy
HAL 37xy family’s is under production with samples available at any time.