This reference design demonstrates a small form factor absolute single-turn magnetic rotary angle encoder circuit design using a high-precision analog AMR 360° angle sensor with sine and cosine differential ratio metric analog outputs and integrated quadrant detection using Hall sensors. The Cortex M0 MCU includes 4MSPS dual sampling 12-bit ADCs and up to 14-bit effective resolution at 250-ksps with hardware averaging for low noise and low latency absolute angle calculation and a 4Mbaud UART for high-speed data transmission. The absolute encoder requires a 5V input supply voltage with ±10% tolerance and offers a bidirectional communication interface using a half-duplex RS-485 transceiver.

• Low noise absolute rotary angle better than 15 ENOB, angle accuracy error less than 0.05° at 25°C and low latency 16us
• Small IC packages enable a compact circular PCB with a diameter of 30mm
• AMR sensor and integrated Hall sensors for quadrant detection enable full 360° measurements and reduce BOM count
• Wide operating magnetic field range 20mT to 1T enables flexible mechanical placement
• MCU with integrated dual 12-bit ADC and up to 128-times oversampling and math accelerator help improve efficiency and reduce system cost
• RS485 transceiver with integrated 120Ω switchable termination in a VSON-10 package help reduce BOM and space

• Servo Drive Position Sensor
• Position Sensor
• Traction Inverter Position Sensor