Analog Devices – The ADMT4000

There are many single-turn 360° absolute position sensors on the market today, but the ADMT4000 is the first single chip sensor with an absolute measurement range of 360°. The sensor IC incorporates a GMR based spiral multiturn sensor, an AMR angle sensor, a signal conditioning IC and has a 46-turn measurement range providing an absolute 0° to 16,560° digital output. The sensor is non-contacting and has the unique ability to measure and track multiple turns of a rotating magnetic field in the absence of electrical power.

The sensor is non-contacting and has the unique ability to measure and track multiple turns of a rotating magnetic field in the absence of electrical power. The operating principle of the sensor is based on Shape Anisotropy, the generation of domain walls in the presence of an external magnetic field. As the external magnetic field rotates, the domain walls propagate through narrow spiral tracks (nanowires) changing the state of each spiral leg element. The spiral elements are fabricated on a Giant Magneto Resistance (GMR) process and the state change is essentially a change in the resistance in the presence of a rotating magnetic field.

The multiturn sensor tracks the movement of the rotating magnetic field without electrical power and when power is reapplied, the signal conditioning IC reads back the state (resistance) of the GMR spiral legs and determines the new turn count state. The multiturn sensor is accurate to a quarter turn (90°) and the ASIC combines the multiturn position with precise angle information from the AMR angle sensor to provide the 0° to 16,560° absolute digital output and is accurate to +/-0.25° over the complete measurement range.

Visit Analog Devices at electronica, C4.125 and chat to the team about the world’s first single chip Multiturn position sensor.

Find more information about the product here: Multiturn Position Sensor Provides True Power-On Capabilities with Zero Power | Analog Devices