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 for Direction Detection * Ultraminiature TDFN6 Package Typical Applications * Rotary Encoders * Batttery-Powered Rotary Position Sensors * Motor Shaft Position Sensors Description The AAT001-10E angle sensor is a low power, high output magnetic sensor element able to provide rotational position measurements when a rotating magnetic field is applied to the sensor. Sine and cosine signals are available for a quadrature output. The sensor element has a resistance of approximately 1.25 M and can be operated at typical battery voltages to conserve power. 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 NVE's 2.5 mm x 2.5 mm x 0.8 mm TDFN6 surface-mount package. Operation Each of the four sensor elements contains 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 magnetic orientation of the layers: NVE Corporation * Pinned Layer Fr ee La ye r Ap pli ed (30 Ma to gne 20 tic 0 O Fi e) eld Angle between pinned and free layers determines sensor resistance Free layer aligns with applied magnetic field 11409 Valley View Road, Eden Prairie, MN 55344-3617 * (952) 829-9217 * www.nve.com AAT001-10E 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 Voltage 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 AAT001-10E TMR Sensor Functional Block Diagram, Marking, and Pinout The AAT001-10E package is marked "FCVe." The device contains four sensing resistors with the pinned layer 90 degrees apart. The resistors are connected as two half-bridges, providing sine and cosine outputs: FCVe Vcc Vcc R3 (Cosine) Cosine Output Cos R2 (Sine) Sine Output Sin R4 (Cosine) GND R1 (Sine) GND Operating Specifications Parameter Resistance (Each Resistor)6 Peak-to-Peak Signal Level Required Applied Magnetic Field Strength Angular Measurement Error, Variable Bias3 Angular Measurement Error, Fixed Bias4 Supply Voltage Offset Voltage Temperature Range of Operation Temperature Coefficient of Resistance TCOV5 Test Condition 25C Operating at 25C Operating Operating Operating Operating Operating at 25C Operating Operating Operating Min. 0.6 130 30 Typ. 1.25 160 -10 -40 Max. 2.5 180 200 3 0.5 5.5 10 125 -0.13 -0.16 Units M mV/V Oe2 Angular Degrees Angular Degrees V mV/V C %/C %/C Absolute Maximum Ratings Parameter Supply Voltage Storage Temperature ESD (Human Body Model) Applied Magnetic Field1 Notes: 1. 2. 3. 4. 5. 6. Min. -40 Typ. Max. 7 170 2,000 Unlimited Units Volts C Volts Oe Large magnetic fields CANNOT damage NVE sensors. 1 Oe (Oersted) = 1 Gauss in air = 0.1 millitesla = 79.8 A/m. Variable Bias means the magnetic field strength at the sensor can vary across the specification range; this is the same as a variable airgap between the bias magnet and the sensor. Fixed Bias means the magnetic field strength at the sensor is constant; this is the same as a fixed airgap between the bias magnet and the sensor. TCOV is the percent change in voltage signal over temperature with a constant supply voltage. Resistance is specified with the saturating magnetic field applied. NVE Corporation * 11409 Valley View Road, Eden Prairie, MN 55344-3617 * (952) 829-9217 * www.nve.com AAT001-10E TMR Sensor Package Drawing - TDFN6 2.5 mm x 2.5 mm Notes: * Dimensions in mm. * The center pad may be left floating or connected to ground. RoHS COMPLIANT (c)NVE Corporation All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. SB-00-024 NVE Corporation * 11409 Valley View Road, Eden Prairie, MN 55344-3617 * (952) 829-9217 * August 4, 2012 www.nve.com AAT001-10E TMR Sensor Datasheet Limitations The information and data provided in datasheets shall define the specification of the product as agreed between NVE and its customer, unless NVE and customer have explicitly agreed otherwise in writing. All specifications are based on NVE test protocols. In no event however, shall an agreement be valid in which the NVE product is deemed to offer functions and qualities beyond those described in the datasheet. Limited Warranty and Liability Information in this document is believed to be accurate and reliable. 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