Analysis of single-ended 6T SRAM cell in 90nm CMOS technology and implementation of charge recycling memory architecture

摘要

As CMOS process technology advances into deep sub-micron era, static leakage power becomes an important design consideration for engineers. Static random access memory (SRAM) occupies over 50% of total transistor counts in a SoC design, and therefore it is essential to minimize its stand-by current for low power applications. This thesis presents a single ended input/output 6T SRAM cell with write-assist (WAcell) feature in 90nm CMOS technology. Without the bit-lines being constantly precharged, the static power of a WAcell is reduced by 6.3X using leakage-biased bit-line technique. The minimized subthreshold currents can be collected to build charge pools and used as a power source to help charge bit lines. The proposed write-assist SRAM memory has reduced overall active power by 42% and standby power by 75% compared to traditional SRAM memory. A complete memory design using WAcell with decoders, write driver and sense amplifiers is also presented in this thesis.