P3 (Power-Performance-Process) Optimization of Nano-CMOS SRAM using Statistical DOE-ILP

Garima Thakral1,  Saraju Mohanty1,  Dhruva Ghai1,  Dhiraj Pradhan2
1University of North Texas, 2University of Bristol


In this paper, a novel design flow is presented for simultaneous P3 (power minimization, performance maximization and process variation tolerance) optimization of nano-CMOS circuits. For demonstration of the effectiveness of the flow, a 45nm single-ended 7-transistor SRAM is used as example circuit. The SRAM cell is subjected to a dual-VTh assignment based on a novel statistical Design of Experiments-IntegerLinear Programming (DOE-ILP) approach. Experimental results show 44.2% power reduction (including leakage) and 43.9% increase in the read static noise margin compared to the baseline design. The process variation analysis of the optimized cell is carried out considering the variability effect in 12 device parameters. A 8x8 array is constructed to show the feasibility of the proposed SRAM cell. To the best of the authors’ knowledge, this is the first study which makes use of statistical Design of Experiments and Integer Linear Programming for optimization of conflicting targets of stability, power in the presence of process variations in an SRAM cell.