A comprehensive analysis of different 7T SRAM topologies to design a 1R1 W bit interleaving enabled and half select free cell for 32 nm technology node

Abstract

In this paper, a single-ended, dual port, 1R1 W seven transistor-based static random access memory bit cell is presented. The cell is designed based on a detailed review of various pre-existing 7T cells. All the cells in the paper are evaluated at 32 nm technology and supply voltage of 0.8 V. The static analysis reveals that the hold/read noise margins for the proposed cell are 324 mV each, whereas the write margin is 488 mV. Successful read and write operation for the cell requires a pulse-width of 5 ps and 0.14 ns, respectively. The temperature variation and process corner analysis are used to justify the reliability for the proposed cell. The former analysis yields 0.15 and 0.24 mV/°C variation in the HSNM/RSNM, and WM for the cell. The current ratio for the cell is comparatively higher than other cells. The leakage power consumption for the cell is 256 pW, while its read and write power consumption are 6 µW and 1.9 µW, respectively. Also, the cell is half select disturbance-free and therefore supports bit-interleaving. This ensures the increased reliability for the cell. All the aforementioned merits for the cells are achieved with a minimal layout area of 0.553 µm2.