Low-Power and Compact Analog-to-Digital Converter Using Spintronic Racetrack Memory Devices

Current-induced domain wall (DW) motion in spintronic racetrack memory promises energy-efficient analog computation using compact magnetic nanowires. This paper explores the feasibility of analog-to-digital converter (ADC) based on current-induced DW motion and introduces an n-bit ADC using n racetrack magnetic nanowires. With each magnetic nanowire having a different configuration granularity, an n-bit binary or gray code is generated simultaneously. The proposed ADC structure achieves 21 fJ/conversion-step at 20 MHz with an area of about 10 μm
²
. The racetrack ADC is suitable for applications requiring dense ADC arrays, such as image sensors. This paper describes one ultrahigh speed digital pixel sensor imaging system benefiting from the racetrack ADC.