SRAM Memory Components Operating at Sub-threshold Voltages

This paper compares the performance of the common 6T SRAM design and an improved 8T design in sub-threshold operation. Optimal parameters for the transistors are derived based on experimental data. The impact of process variation on SRAM’s performance and SNM are analyzed, together with redundancy as an alternative approach to reduce failure rate. Finally, in addition to bit-cells, various types of sense amplifiers operating in the subthreshold region are compared using metrics of resolution speed and input-referred offset voltage. Ways to improve these metrics such as body-biasing and increasing output impedance were also examined.