A 100MHz to 1GHz, 0.35V to 1.5V Supply 256 x 64 SRAM Block Using Symmetrized 9T SRAM Cell with Controlled Read

Abstract

In this paper, we present dynamic voltage and frequency Managed 256 x 64 SRAM block in 65 nm technology, for frequency ranging from 100 MHz to 1 GHz. The total energy is minimized for any operating frequency in the above range and leakage energy is minimized during standby mode. Since noise margin of SRAM cell deteriorates at low voltages, we propose static noise margin improvement circuitry, which symmetrizes the SRAM cell by controlling the body bias of pull down NMOS transistor. We used a 9T SRAM cell that isolates Read and hold noise margin and has less leakage. We have implemented an efficient technique of pushing address decoder into zigzag- super-cut-off in stand-by mode without affecting its performance in active mode of operation. The read bit line (RBL) voltage drop is controlled and pre-charge of bit lines is done only when needed for reducing power wastage.