Trends in low-voltage embedded RAMs

Low-voltage high-density embedded (e-) RAMs, focusing on RAM cells and peripheral circuits, are described. First, challenges and trends in low-voltage e-RAMs are described based on the S/N issue of RAM cells, and leakage and speed-variation issues of peripheral circuits. Next, state-of-the-art low-voltage e-DRAMs and e-SRAMs are investigated, focusing on leakage reduction. Finally, future prospects for e-RAMs are discussed in terms of low-voltage designs.