Description
The AMR3108A is a contactless, high-precision, and
high-speed magnetic rotary encoder sensor, which
integrated with anisotropic magnetoresistance (AMR)
sensors and CMOS digital signal processing circuitry.
The AMR3108A senses the single pole-pair magnet
rotation above the chip by AMR sensors, collects the
rotating magnetic field signal, transmits it to the digital
processing unit, calculates the rotation angle and
outputs 12-bit absolute position signals.
The signal period of AMR3108A is 180° rotation
angle. Using the reserved inverted switch interface, it
can be extended to the detection of 360° rotation angle.
AMR3108A outputs 12-bit absolute position signal
through SPI communication protocol in a 180°
rotation period. At the same time, it is able to output
A/B phase programmable incremental position signal
with 1 to 1024 pulse and programmable zero-point
(Z phase) signal. AMR3108A also provides inverted
UVW output, analog and PWM signals, with rotational
speed up to 20,000 RPM.

Features and Benefits
••Anisotropic magnetoresistance (AMR) technology
••Contactless measurement
••Available in SPI, ABZ differential, UVW, Analog and
PWM interfaces
••12-bit absolute position output in SPI mode
••Programmable A/B interpolation factors: ×1 to ×1024
••Programmable Z pulse width in 1LSB/2LSB/4LSB/90°
••Programmable inverted UVW output resolution in
1 to 16 pole-pair
••Programmable analog clamping voltage and PWM
frequency
••Programmable zero position
••Angular repeatability < ±0.1°
••Speeds up to 20,000 RPM
••Adaptive supply voltage: 3.3 V to 5 V

Applications
••Contactless angular position measurement
••Brushless motor position sensing
••Rotary speed sensing
••Stepper motor