Leakage Current Stability Analysis for Subthreshold SRAM

Low-power memories typically operate in the subthreshold region of the device; however, as the supply voltage continues to decrease, the impact of leakage current on SRAM stability becomes more significant. The traditional method of measuring static noise tolerance only considers the effect of voltage, and the measurement results are not accurate enough. Therefore, this paper proposes a leakage-current-based stability analysis that provides better metrics, reads current noise tolerance (RINM) and writes current noise tolerance (WINM) to measure the stability of subthreshold SRAMs. Both currents and voltages were taken into account. The results demonstrate that the method is more accurate than the conventional method under subthreshold levels.