An Energy Efficient Match-Line Sensing Scheme for High-Speed and Highly-Reliable Ternary Content Addressable Memory
Ternary Content Addressable Memory (TCAM) is widely used in the network routers for performing high speed and deterministic table lookups. The high power consumption and reliability of the operation are the major issues with TCAM. The Match-Line (ML) sense amplifiers (MLSAs) used in the TCAM for match detection consume the significant portion of the TCAM power. The sensing schemes which isolate the sensing unit of the sense amplifier from the large and variable ML capacitance can significantly reduce the TCAM power and increase the speed, but they suffer from the low reliability of the operation due to small voltage margin between matched and the mismatched MLs. This paper presents a novel scheme which in addition to isolating the sensing unit of the sense amplifier from the ML capacitance and employs the feedback in the MLSA offering the large voltage margin between matched and the mismatched MLs for the reliable operation. The proposed design is much simpler without the need for any specially designed devices required to ensure the reliable operation of the memory.