A 256×128 Energy-Efficient TCAM with Novel Low Power Schemes

Abstract

Novel low power schemes for energy-efficient ternary content-addressable memory (TCAM) are presented in this paper. The butterfly match-line scheme is based on the pseudo-footless clock-data pre-charged architecture. It connects each pipelined stage in a butterfly style which significantly decreases both search time and power consumption. For applications like IP-address forwarding in a network router, a new don't-care based power gating and don't-care based hierarchical (DCBH) search-line scheme are proposed. The search-line is divided into global search-line (GSL) and local search-line (LSL) which is controlled by don't-care state in DCBH search-line scheme. Therefore, the power consumption on search line is reduced without any search time overhead. Besides, the power saving of the standby power is achieved by power gating technique. The proposed 256 times 128 bit TCAM has been implemented with TSMC 0.13 um CMOS technology. It shows 0.55 ns of match evaluation time on search operation with 0.29 fJ/bit/search of energy efficiency.