Design of a spin–orbit-torque-based self-terminated nonvolatile register for a write/leakage-energy-minimized backup operation

Abstract

A self-terminated nonvolatile (NV) register that is a key component of a energy-efficient LSI is proposed and its impact on minimizing write and leakage energies during a backup operation before a power-off mode is presented by combining spin–orbit-torque (SOT) devices with CMOS circuitry. The self-terminated NV-register can automatically cut off the write current pulse by continuously monitoring the voltage change due to the state transition of the SOT device. Moreover, the write completion signals can be utilized for a flag whether the circuit can go into the power-off mode which results in the minimization of leakage energy consumption. A case study is performed using a 45nm CMOS technology which results in 71% of total energy reduction in the backup operation compared to that of a typical worst-case design.