Mohsen Jafari - School of Electrical and Computer, Collage of Engineering, University of Tehran, Tehran, Iran
Mohsen Imani - School of Electrical and Computer, Collage of Engineering, University of Tehran, Tehran, Iran

this paper focuses on introducing a new circuitry method in order to suppress Negative Bias Temperature Instability (NBTI) effects on SRAM cells. NBTI effect canseverely degrade the power and stability characteristics of SRAM cells during their operation years. The proposed method can be applied to every single cell and catch in order to suppress the NBTI variability in the threshold voltage of the top PMOS transistors. The method uses a feedback currentmirror loop to set the body voltage of the PMOS when their threshold voltages are increase due to NBTI effect. Differentcell topologies are employed in order to evaluate the effectiveness of the method. The comparison with the conventional SRAM shows that new structure with suppressing the NBTI can improved the read SNM 10.5%(11%, 10.2%) and hold SNM 36%(25%, 9.6%) for 5T, 6T and 9T structure respectively

NBTI, SRAM, Low Power, Current Mirror