Spin-torque memristor based offset cancellation technique for sense amplifiers

Abstract

In this study, we propose an offset cancellation technique with the spin-torque memristors where are unpredictable threshold voltage changes of transistors that results in the input referred random offset (IRRO) of amplifiers. Motivated by this fact, this study focuses on the IRRO cancellation in sense amplifiers with the aid of the spin-torque memristor technology. The spin-torque memristors in series perform less resistance and process variations from parallel connection. The resistance value of the spin-torque memristor was regarded as frozen when the current flow over the spin-torque memristor is lower than its critical switching current value. In fact, the proposed structure employs a non-destructive sensing scheme in order to achieve a relatively large sense margin by reducing the IRRO. Our main idea is to reduce or eliminate the IRRO exploiting the spin-torque memristors for providing the current matching on the input transistors of the voltage comparator. In particular, the overwrite problem of the spin-torque memristor was solved by setting the critical switching current of the spin-torque memristor to be greater than a current value corresponding to maximum the IRRO value. We evaluated the IRRO cancellation technique on the proposed comparator or sense amplifier using 45nm predictive CMOS technology. Although sense amplifiers are targeted in this study, our technique can be applied to any analog amplifier suffering from the IRRO.