TERNARY CONTENT ADDRESSABLE MEMORY (TCAM) CELLS WITH SMALL FOOTPRINT SIZE AND EFFICIENT LAYOUT ASPECT RATIO

摘要

Ternary CAM cells are provided that have extremely small layout footprint size and efficient layout aspect ratios that enhance scalability. The cells also have high degrees of symmetry that facilitate high yield interconnections to bit, data and match lines. A 16T ternary CAM cell includes first and second pairs of access transistors that extend adjacent a first side of the cell, and first and second pairs of cross-coupled inverters that extend adjacent a second side of the cell. First and second halves of a 4T compare circuit are also provided. The first half of the 4T compare circuit is positioned so that it extends between the first pair or access transistors and the first pair of cross-coupled inverters. Similarly, the second half of the 4T compare circuit is positioned so that it extends between the second pair of access transistors and the second pair of cross-coupled inverters.