Reliable write assist low power SRAM cell for wireless sensor network applications

In this study, the authors have proposed a Write Assist Low Power 11T (WALP11T) SRAM cell. To analyse its performance in terms of major design metrics, the proposed cell has been compared with contemporary SRAMs like the Fully Differential 8T (FD8T), Single-Ended Disturb Free 9T (SEDF9T), Bit-interleaving architecture supporting 11T (BI11T), Self-refreshing Logic-based 12T (WWL12T) and Differential 12T (D12T) cells. The proposed cell exhibits significantly shorter read/write delay when compared to most comparison cells. It shows considerably higher read stability and write ability than that of FD8T and SEDF9T/D12T/WWL12T, respectively. Moreover, WALP11T dissipates significantly lower leakage power in comparison to the majority of comparison cells and exhibits 2.21 × /1.18 × lower read power delay product ( R PDP ) than that of BI11T/D12T and 5.12 × /1.39 × /1.09 × lower write power delay product ( W PDP ) than that of BI11T/WWL12T/D12T. The proposed cell consumes considerably lower area than WWL12T/D12T and shows highly reliable operation when subjected to the harsh process, voltage and temperature variations at both Slow NMOS-Fast PMOS and Fast NMOS-Slow PMOS corners. For all these improvements, WALP11T shows longer read/write delay than FD8T, higher leakage power and power delay product than BI11T and FD8T/SEDF9T, respectively, at V DD = 0.3 V.

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