Improve CAM power efficiency using decoupled match line scheme

Abstract

Content addressable memory (CAM) is widely used in many applications that require fast table lookup. Due to the parallel comparison feature and high frequency of lookup, however, the power consumption of CAM is usually significant. In this paper we propose a decoupled match line scheme which combines the performance advantage of the traditional NOR-type CAM and the power efficiency of the traditional NAND-type CAM. In our design, a CAM word is divided into two segments, and then all the CAM cells are decoupled from the match line. By minimizing both the match line capacitances and switching activities, our design can largely reduce the CAM power dissipated in search operations. The results measured from the fabricated chip show that without any performance penalty our design can reduce the search energy consumption of the CAM by 89% compared to the traditional NOR-type CAM design.