New Position Sensors Featuring TMR and Vertical Hall Elements Combine Accuracy with Built-in Redundancy for Safety-Critical Systems

Published  June 28, 2022   0
L Lakshita
Magnetic Position Sensors

Allegro MicroSystems, Inc. has launched the new A33110 and A33115 magnetic position sensors that combine vertical Hall technology (VHT) with cutting-edge tunneling magnetoresistance (TMR) technology in a single sensor package and are designed for advanced driver assistance systems (ADAS) applications which require high levels of accuracy and heterogeneous signal redundancy. These new sensors are ASIL D-compliant and enable accurate safety checks, including low-field and missing-magnet detection.

These sensors provide magnetic angle sensing via both the primary (TMR) and secondary (vertical Hall) transducers, each of which are processed by two independent channels, each with independent regulators and temperature sensors. This unique configuration enables the high levels of safety and diagnostic coverage needed for automated driving, including on-chip channel-to-channel angle comparison and independent processing in digital signal paths, with no shared digital resources. 

Key Features

  • Primary TMR channel capable of 14-bit noise-free resolution 

  • Secondary channel capable of 10-bit noise-free resolution

  • Wide operating voltage (3.7 to 18 V) enables direct connection to vehicle battery

  • Linearization to reduce error from misalignment between the sensor and target magnet 

  • AEC-Q100 grade 1

  • Designed to meet ASIL D requirements when used in conjunction with appropriate system-level control 

Advanced algorithms in these sensors deliver the fast response time, independent gain/offset correction, angle calculation, and linearization capabilities demanded by safety-critical ADAS applications. Moreover, the A33115 also includes a turns counter that tracks motion in 90-degree increments and a low-power mode with a user-programmable duty cycle that reduces power consumption when the IC is in a key-off position.