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Product Specifications and Features The magnetic field sensor consists of three die: an AMR angle sensor, an ASIC, and a GMR spiral. Each component contributes to the sensor's high precision and functionality. The AMR angle sensor provides accurate 180-degree angle information, while the GMR spiral's quadrant sensor complements it to achieve 360-degree coverage. By combining the quadrant data with the precise 180-degree angle information from the AMR sensor, the system attains complete 360-degree coverage. The ASIC then integrates this data with the multi-turn sensor to deliver absolute position across the sensor's 46-turn range, while maintaining an accuracy of ±0.25 degrees. However, the sensor must operate within a specific magnetic window of 16 mT to 31 mT to ensure optimal performance. Failure to remain within this range can lead to insufficient energy to move the domain walls or cause saturation and unintended resets. C h a p t e r 6 | A D M T 4 0 0 0 D e s i g n , I m p l e m e n t a t i o n , a n d A p p l i c a t i o n s Shielding and Environmental Protection In demanding applications, sensor robustness is essential. ADI has developed a reference design magnet featuring an integrated shield to ensure reliable performance in harsh environments. The shield's two-part design, consisting of a rotating component and a PCB shield with standoffs, protects against straight fields from all angles. When tested with a ±5 mT straight field, the combined shields demonstrate 85-90% effectiveness, safeguarding the sensor's integrity under challenging conditions. Sensor Reset Methods Resetting the sensor is a process that ensures a known good state following transportation, assembly, or after exposure to strong magnetic fields. By turning the sensor more than 46 times, you can clean the spiral of any unwanted domain walls, much like using a pipe cleaner. Exposing the sensor to a strong magnetic field greater than 55 mT, whether with an external magnet, the system magnet, or a small coil embedded in the PCB beneath the sensor, can also trigger a reset. ADI offers a reference design for the reset circuitry to simplify the reset process. It can be connected externally and used once during final assembly to reset the sensor's maximum turn count. Engineers can apply their potential in position-tracking applications by understanding the intricacies of magnetic position sensors, from their nanowire spiral structure to their key components and application considerations. With ADI's reference designs and guidance, integrating these sensors into systems becomes seamless, enabling precision and reliability even in the most challenging conditions. 20 Engineering Reliable Industrial Automation With Sensor Fusion