AMR Angle 2 Click is a compact add-on board containing an anisotropic magnetoresistive measurement solution ideal for either angle or linear position measurements. This board features the ADA4570, an integrated AMR angle sensor with an integrated signal conditioner and differential outputs from Analog Devices. The ADA4570 delivers amplified differential cosine and sine output signals, with respect to the angle measuring from 0° to 180° when the magnetic field is rotating in the x-axis and the y-axis (x-y) plane, processed later by MAX11122, SAR ADC, which forwards the digital angle information to MCU via SPI interface for further processing. This Click board™ is suitable for absolute position measurement (linear and angle), contactless angular measurement and detection, magnetic angular position sensing, actuator control and positioning, and more.

AMR Angle 2 Click as its foundation uses the ADA4570, an anisotropic magnetoresistive (AMR) sensor with integrated signal conditioning amplifiers and analog-to-digital converter (ADC) drivers from Analog Devices. It consists of two dies within one package, an AMR sensor, and a fixed gain instrumentation amplifier producing two differential analog outputs that indicate the angular position of the surrounding magnetic field. This amplified differential cosine and sine output signals are delivered with respect to the angle when the magnetic field is rotating in the x-axis and the y-axis (x-y) plane.

The ADA4570 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, so the magnetic angle calculated from the sine and cosine 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).

As mentioned before, alongside the AMR sensor, this Click board™ also contains one high-speed, low-power, serial output successive approximation register (SAR) analog-to-digital converter (ADC), the MAX11122 from Analog Devices. It processes sine and cosine outputs and then forwards them to the MCU via the SPI interface for further processing. Apart from the SPI communication lines, this Click board™ uses several more pins on the mikroBUS™ such as CST and EOC, routed to the PWM and INT pins of the mikroBUS™ socket, representing the signals with which the AD conversion starts and the signal indicating the completion of the conversion itself, respectively.

Also, the ADA4570 has an integrated temperature sensor that provides a voltage ratiometric to the ADA4570 supply voltage at the AN pin of the mikroBUS™ socket used to monitor the system's operating temperature and provide the reference for further calibration.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

• Interface: Analog, SPI
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Rotation Angle: Min. 0 deg, Max. 180 deg
• Angular Error: ±0.1 deg
• Resolution: 12 bits
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +150°C

• Schematic
• MAX11122 Datasheet
• ADA4570 Datasheet
• mikroSDK
• LibStock