New Dual-Die Stray-Field Compensated 3D HAL Sensors

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Highly flexible device architecture supports various digital interfaces (SPI, PWM output and SENT according to SAE J2716)

Enabling stray-field compensated position detection while addressing the need for ISO 26262 compliant developments are the new HAR 3900 and HAR 3930 Hall sensors by TDK Corporation. Applications include industrial and automotive such as steering angle position detection, gear shifters, brake stroke position sensors, position detection in transmission systems and accelerator pedal position detection. 

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The 3D HAL pixel-cell technology, which accurately measures magnetic fields is the core of the HAR 39xy sensors. They enable angular measurements up to 360° with ferrite 2-pole magnets in addition to linear measurements up to 35 mm by using two-pole bar magnets. The stray-field robust position detection can take both measurement types with additional 3D measurements resulting in two independent angles for each die. 

The HAR 39xy features a powerful DSP responsible for fast signal processing and an embedded microcontroller that performs the interface configuration and supervision of the Functional Safety related tasks.

The HAR 39xy feature 3D magnetic-field measurement capability and 2D stray-field robust position detection. HAR 3930 has PWM and SENT (SAE J2716 rev. 4) output with additional switch output while HAR 3900 offers measurement data available via a high-speed SPI interface. HAR 3900 also provides temperature-compensated raw values of the magnetic field in X, Y and Z direction via the SPI interface while offering various low-power modes. 

Each HAR 39xy sensor contains two independent dies placed upon each other that are mechanically separated and electrically insulated. They measure almost the same magnetic field, therefore ensure synchronous output signals. Redundant sensor solutions in a single package reduce system costs while at the same time increase system reliability due to smaller PCBs and fewer solder joints. 

Other features include:

• Stray-field robust position detection (linear and rotary up to 360°) covering ISO 11452-8 requirements
• Compensation of stray-fields with gradients for applications with 180° rotation
• Real 3D magnetic field measurement of BX, BY and BZ
• Transmission of position information, up to two calculated angles, magnetic-field amplitude and/or chip temperature
• Accuracy of ±0.5° @ 10 mT for rotary setups
• Flux density amplitude range: 10 mT… 130 mT, down to 5 mT with reduced accuracy
• Wide supply voltage range: 3.0 V to 5.5 V (HAR 3900), 3.0 V to 18 V (HAR 3930)
• Suitable for automotive applications due to a wide ambient temperature range from -40 °C to 160 °C

The sensors are SEooC and ASIL B ready according to ISO 26262, thus enabling ASIL D developments on the system level.

With a flexible architecture, HAR 39xy offers a wide range of configurations for suitable operation mode in any given task. 

The HAR 3900 and HAR 3930 are available in a small SSOP16 package. Samples can be obtained on request. Production begins in the second quarter of 2022.