Data Sheet AAT001-10E TMR Angle Sensor Key Features Tunneling Magnetoresistance (TMR) Technology Very High Output Signal Without Amplification Wide Airgap Tolerance Very High Resistance for Extremely Low Power Sine and Cosine Outputs Available Ultraminiature TDFN6 Package Typical Applications Rotary Encoders Automotive Rotary Position Sensors Motor Shaft Position Sensors Knob Position Sensors Description The AAT001-10E angle sensor is a unique array of four Tunneling Magnetoresistance (TMR) elements rotated at 90 degree intervals in the package and connected in a bridge configuration. The output can be configured to represent the sine and cosine functions of the magnetic field applied to the sensor. Each TMR sensor element has a resistance of approximately 1.25 megaohms. Outputs are proportional to the supply voltage and peak-to-peak output voltages are much larger than other sensor technologies. The part is packaged in NVEs 2.5 mm x 2.5 mm x 0.8 mm TDFN6 surface mount package. Operation Each sensor elements contain two magnetic layers: a pinned, or fixed direction layer and a movable- direction, or free layer. The diagram below illustrates the configuration, using arrows to represent the two layers: Angle between Pinned and Free layers determines sensor resistance Free layer aligns with Applied Magnetic Field NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 (952) 829-9217 www.nve.com Free Layer Applied Magnetic Field (30 to 200 Oe) Pinned LayerAAT001-10E TMR Sensor An external magnet provides a saturating magnetic field (30 to 200 Oe) in the plane of the sensor, as illustrated below for a bar magnet and a split-pole magnet: The sensor element free layers will align with the external field. As the applied field changes direction, the angle between the free layer and the pinned layer changes, changing the resistance of TMR elements, which changes the device output voltages. Variations in the air gap between the magnet and the sensor element will cause slight changes in the output depending on the size and strength of the external magnet. The following chart shows a typical sensor output versus the angle of applied field using a 12 mm diameter, 4 mm thick split-pole ferrite magnet and a 5 V supply with three different air gaps: Angle Sensor Output with Variations in Airgap, 5V Supply 2.9 Cosine, 3mm 2.8 Sine, 3mm Cosine, 4mm 2.7 Sine, 4mm Cosine, 5mm 2.6 Sine, 5mm 2.5 2.4 2.3 2.2 2.1 2 0 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 Degrees of Rotation NVE Corporation 11409 Valley View Road, Eden Prairie, MN 55344-3617 (952) 829-9217 www.nve.com Voltage