A 16-Mb CMOS SRAM with a 2.3- mu m/sup 2/ single-bit-line memory cell

摘要

A novel architecture that enables fast write/read in poly-PMOS load or high-resistance polyload single-bit-line cells is developed. The architecture for write uses alternate twin word activation (ATWA) with bit-line pulsing. A dummy cell is used to obtain a reference voltage for reading. An excellent balance between a normal cell signal line and a dummy cell signal line is attained using balanced common data-line architecture. A newly developed self-bias-control (SBC) sense amplifier provides excellent stability and fast sensing performance for input voltages close to V/sub CC/ at a low power supply of 2.5 V. The single-bit-line architecture is incorporated in a 16-Mb SRAM, which was fabricated using 0.25- mu m CMOS technology. The proposed single-bit-line architecture reduces the cell area to 2.3- mu m/sup 2/, which is two-thirds of a conventional two-bit-line cell with the same processes. The 16-Mb SRAM, a test chip for a 64-Mb SRAM, shows a 15-ns address access time and a 20-ns cycle time.