Robust Offset-Cancellation Sense Amplifier for an Offset-Canceling Dual-Stage Sensing Circuit in Resistive Nonvolatile Memories

Abstract

With technology scaling, achieving a target read yield of resistive nonvolatile memories becomes more difficult due to increased process variation and decreased supply voltage. Recently, an offset-canceling dual-stage sensing circuit (OCDS-SC) has been proposed to improve the read yield by canceling the offset voltage and utilizing a double-sensing-margin structure. In this paper, an offset-canceling zero-sensing-dead-zone sense amplifier (OCZS-SA) combined with the OCDS-SC is proposed to significantly improve the read yield. The OCZS-SA has two major advantages, namely, offset voltage cancellation and a zero sensing dead zone. The Monte Carlo HSPICE simulation results using a 65-nm predictive technology model show that the OCZS-SA achieves 2.1 times smaller offset voltage with a zero sensing dead zone than the conventional latch-type SAs at the cost of an increased area overhead of 1.0% for a subarray size of 128 × 16.