Breaking POps/J Barrier with Analog Multiplier Circuits Based on Nonvolatile Memories

Abstract

Low-to-medium resolution analog vector-by-matrix multipliers (VMMs) offer a remarkable energy/area efficiency as compared to their digital counterparts. Still, the maximum attainable performance in analog VMMs is often bounded by the overhead of the peripheral circuits. The main contribution of this paper is the design of novel sensing circuitry which improves energy-efficiency and density of analog multipliers. The proposed circuit is based on translinear Gilbert cell, which is topologically combined with a floating nonlinear resistor and a low-gain amplifier. Several compensation techniques are employed to ensure reliability with respect to process, temperature, and supply voltage variations. As a case study, we consider implementation of couple-gate current-mode VMM with embedded split-gate NOR flash memory. Our simulation results show that a 4-bit 100x100 VMM circuit designed in 55 nm CMOS technology achieves the record-breaking performance of 3.63 POps/J.