Integrated AMR Angle Sensor and Signal Conditioner with Differential Outputs

The ADA4570 is an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and analog-to-digital converter (ADC) drivers. The ADA4570 produces two differential analog outputs that indicate the angular position of the surrounding magnetic field.

The ADA4570 consists of two die within one package, an AMR sensor, and a fixed gain instrumentation amplifier. The ADA4570 delivers amplified differential cosine and sine output signals, with respect to the angle, when the magnetic field is rotating in the x-axis and the y-axis (x-y) plane. The output voltage range is ratiometric to the supply voltage.

The sensor contains two Wheatstone bridges, at a relative angle of 45° to one another. A complete rotation of a dipole magnet produces two periods on the sinusoidal outputs. Therefore, the magnetic angle (α) calculated from the SIN and COS differential outputs represents the physical orientation of the magnet with respect to the ADA4570 in the 0° to 180° measurement range. Within a homogeneous field in the x-y plane, the output signals of the ADA4570 are independent of the physical placement in the z direction (air gap).

The ADA4570 is available in an 8-lead SOIC package.

APPLICATIONS

* Absolute position measurement (linear and angle)

* Brushless dc motor control and positioning

* Actuator control and positioning

* Contactless angular measurement and detection

* Magnetic angular position sensing

* Contactless angular measurement

* High precision 180° angle sensor

* Typical angular error of ±0.1°

* Low output noise of 850 μV rms

* Sine and cosine differential outputs

* Ratiometric analog voltage outputs

* Negligible hysteresis

* SAR or Σ-Δ ADC compatible

* Temperature compensated AMR bridge