Process Tolerant and Power Efficient SRAM Cell for Internet of Things Applications

The use of Internet of Things (IoT) applications become dominant in many systems. Its on-chip data processing and computations are also increasing consistently. The battery enabled and low leakage memory system at subthreshold regime is a critical requirement for these IoT applications. The cache memory designed on Static Random-Access Memory (SRAM) cell with features such as low power, high speed, and process tolerance are highly important for the IoT memory system. Therefore, a process tolerant SRAM cell with low power, improved delay and better stability is presented in this research paper. The proposed cell comprises 11 transistors designed with symmetric approach for write operations and single ended circuit for read operations that exhibits an average dynamic power saving of 43.55% and 47.75% for write and 35.59% and 36.56% for read operations compared to 6 T and 8 T SRAM cells. The cell shows an improved write delay of 26.46% and 37.16% over 6 T and 8 T and read delay is lowered by 50.64% and 72.90% against 6 T and 10 T cells. The symmetric design used in core latch to improve the write noise margin (WNM) by 17.78% and 6.67% whereas the single ended separate read circuit improves the Read Static Noise Margin (RSNM) by 1.88x and 0.33x compared to 6 T and 8 T cells. The read power delay product and write power delay product are lower by 1.94x, 1.39x and 0.17x, 2.02x than 6 T and 8 T cells respectively. The lower variability from 5000 samples validates the robustness of the proposed cell. The simulations are carried out in Cadence virtuoso simulator tool with Generic Process Design Kit (GPDK) 45 nm technology file in this work.