Content-Addressable Memory (CAM) circuits and Performance comparison of positive feedback matchline sensing circuits

Abstract

CAM is used to implement lookup-table function in a single clock cycle using dedicated comparison circuitry. CAMs are especially popular in network routers for packet forwarding and classification, but they are also beneficial in a variety of other applications that require high-speed table lookup. The main CAM design challenge is to reduce power consumption associated with the large amount of parallel active circuitry, without sacrificing speed or memory density. Ternary content addressable memories (TCAMs) are hardware based parallel lookup tables with bit-level masking capability. Ternary content-addressable memories (TCAMs) can perform high-speed and deterministic table lookups. However, its main drawback is high power consumption. A significant portion of the TCAM power is consumed by matchline sense amplifiers (MLSAs) for match detection. This work compares circuit techniques for reducing TCAM power consumption. The ML sensing energy is reduced by employing positive-feedback ML sense amplifiers (MLSAs).