Design of a Low-Voltage Analog-to-Digital Converter Using Voltage-Controlled Stochastic Switching of Low Barrier Nanomagnets

Their inherent stochasticity makes nanoscale devices prospective candidates for low-power computations. Such devices have been demonstrated to exhibit probabilistic switching between two stable states to achieve stochastic behavior. Recently, superparamagnetic nanomagnets (having low-energy barrier EB 1 kT) have shown promise of achieving stochastic switching at gigahertz rates, with very low currents. On the other hand, voltage-controlled switching of nanomagnets through the magneto-electric effect has shown further improvements in energy efficiency. In this letter, we model a voltage-controlled spintronic device based on superparamagnetic nanomagnets exhibiting telegraphic switching characteristics and analyze its behavior under the influence of external bias. Subsequently, we show that the device leverages the voltage-controlled stochasticity in performing low-voltage 8 bit analog-to-digital conversions. This eliminates the need for comparators, unlike the CMOS-based Flash analog-to-digital converters (ADCs). This device allows for a simple and compact design of low-power approximate ADCs, which have become quintessential elements with the recent developments in neuromorphic computing and “Internet of Things.”