Estimation of Static Noise Margin by Butterfly Method Using Curve-Fitting Technique

Estimation of static noise margin (SNM) is believed to be most important step of static random access memory (SRAM) bitcell design. Moreover, the measurement of bitcell stability is a critical issue with scaling of complementary metal-oxide semiconductor (CMOS) technology. Available techniques to find SNM are time consuming and difficult to implement by circuit simulation tool, so there is need of alternate method that can estimate SNM easily. In this article, we present a new method of SNM calculation that is based on curve fitting technique. We calculated SNM of six transistor (6T) SRAM cell with proposed method and established graphical method by varying cell ratio. The correlation coefficient of SNM was 0.99 that indicate proposed technique may be substitution for SNM calculation over conventional graphical method. We believe that we have developed an innovative solution for stability estimation of SRAM bitcell in nanometer technology