A fully-differential subthreshold SRAM cell with auto-compensation

Abstract

SRAM cell stability is a major challenge in subthreshold SRAM design. In this paper, a robust, fully-differential subthreshold 10-transistors SRAM cell with auto-compensation is proposed. With the auto-compensation mechanism, the proposed cell exhibits better hold static noise margin (SNM). The cell structure also prevents storage nodes from bitline noise interference, thus improving read SNM. Moreover, better write ability is achieved by applying write assist technique. Based on UMC 90nm CMOS technology, simulation results shows that at 200mV supply voltage, the proposed cell has 1.22X hold SNM improvement, 2.09X read SNM improvement, and 2.03X write margin improvement compared to the conventional 6T SRAM cell.