Content-addressable memory (CAM) circuits and architectures: A tutorial and survey

K. Pagiamtzis and A. Sheikholeslami, “Content-addressable memory (CAM) circuits and architectures: A tutorial and survey,” IEEE Journal of Solid-State Circuits, vol. 41, no. 3, pp. 712–727, Mar 2006.
This paper made the Journal of Solid-State Circuits List of Most-Read Articles for the first half of 2006.

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Abstract

We survey recent developments in the design of large-capacity content-addressable memory (CAM). A CAM is a memory that implements the lookup-table function in a single clock cycle using dedicated comparison circuitry. CAMs are especially popular in network routers for packet forwarding and packet classification, but they are also beneficial in a variety of 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. In this paper, we review CAM- design techniques at the circuit level and at the architectural level. At the circuit level, we review low-power matchline sensing techniques and searchline driving approaches. At the architectural level we review three methods for reducing power consumption.