A Low-Power 8-bit Spintronic Rotary Encoder With Single-Track Gray Code Based on Spin-Hall Effect-Driven Domain Wall Motion

Abstract

This article introduces a low-power spintronic rotary encoder capable of 8-bit analog-to-digital conversion. The proposed encoder leverages spin-Hall effect-driven domain wall motion (SHE-DWM) within a ring-shaped device to translate an analog input current into a proportional angular displacement of magnetic domain walls (DWs). This angular displacement is subsequently digitized using a single-track gray code (STGC) scheme, which ensures reliable readout through its unit-distance code property and high encoding efficiency. Simulations conducted using a 130 nm CMOS process technology indicate that the encoder achieves a 20 MHz operating frequency with a total power consumption of $54.8~\mu $ W, representing a 2.35 times reduction compared to a prior SHE-DWM-based converter. As a fully CMOS-compatible device, the proposed encoder is well-suited for monolithic integration into area-efficient, multi-channel data conversion systems.