Switching pMOS Sense Amplifier for High-Density Low-Voltage Single-Ended SRAM

A switching pMOS sense amplifier (SPSA) is proposed for high-speed single-ended static RAM sensing. By using the same pull-up pMOS transistor for sensing and precharging the bit-line, the performance is enhanced, and the power consumption is reduced. A keeper that compensates bit-line leakage is also employed, and a minimum operating voltage of 0.51 V is obtained. Compared to the previous dynamic pMOS sense amplifier and AC-coupled sense amplifier (ACSA), the sensing time is improved by 55% and 10%, respectively, and the power consumption is reduced by 12% and 44%, respectively. Furthermore, the area of the SPSA is estimated to be 43% smaller than that of the ACSA. Although the SPSA has a 59% larger area than a dynamic pMOS sense amplifier, the area overhead can be mitigated by allocating a larger number of cells per bit-line (CpBL) because the performance of the SPSA is still better than that of the dynamic pMOS, even with a CpBL that is two times larger.