Match‐line control unit for power and delay reduction in hybrid CAM

Abstract

Abstract Content addressable memory (CAM) is a hardware search engine utilised for accelerating translation and table look‐up in network routers and data processing systems. This article proposes a NAND‐NOR match‐line (ML) based CAM architecture with the main goals of elevating search performance and energy efficiency. A competent ML control unit (MLCU) is introduced to provide a short discharge path for output match‐line after processing the ML sections. In this architecture, tag mismatch based on memory traces is utilised (in NAND‐MLs) to deactivate redundant NOR‐MLs in an attempt to reduce the overall ML switching activity. Based on the decision of NAND‐ML partition, the MLCU restores the charge to reduce ML glitches during the evaluation phase. Match‐line delay of the proposed 64×32‐bit hybrid CAM is 366.90 ps in a standard 45‐nm technology at 1 V, which is 56.51% and 72.55% reductions compared to a conventional CAM and a segmented CAM, respectively. Reduction in precharge power and search power of the presented CAM leads to 6× enhancements of power‐delay‐product from existing hybrid CAMs. The proposed CAM can operate up to low supply voltages by dissipating only 0.10 fJ/bit/search at 0.5 V.

Keywords

• content‐addressable storage
• low‐power electronics
• memory architecture
• NAND circuits