Integrated AMR Angle Sensor and Signal Conditioner

The ADA4571 is an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and ADC drivers. The ADA4571 produces two analog outputs that indicate the angular position of the surrounding magnetic field.

The ADA4571 consists of two die within one package, an AMR sensor, and a fixed gain (G = 40 nominally) instrumentation amplifier. The ADA4571 delivers clean and amplified cosine and sine output signals related to the angle of a rotating magnetic field. 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 rotating magnetic field in the x-y sensor plane delivers two sinusoidal output signals with the double frequency of the angle (α) between sensor and magnetic field direction. Within a homogeneous field in the x-y plane, the output signals are independent of the physical placement in the z direction (air gap).

The ADA4571 is available in an 8-lead SOIC package.

Product Highlights

* Contactless angular measurement.

* Measures magnetic field direction rather than field intensity.

* Minimum sensitivity to air gap variations.

* Large working distance.

* Excellent accuracy, even for weak saturation fields.

* Minimal thermal and lifetime drift.

* Negligible hysteresis.

* Single chip solution.

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

* High precision 180° angle sensor

* Maximum angular error of 0.5°

* Analog sine and cosine outputs

* Ratiometric output voltages

* Low thermal and lifetime drift

* SAR or Σ-∆ analog-to-digital converter (ADC) drive capable

* Magnetoresistive (MR) bridge temperature compensation mode