A Complete Charge Recycling TCAM with Checkerboard Array Arrangement for Low Power Applications

Katsumi DOSAKA  Daisuke OGAWA  Takahito KUSUMOTO  Masayuki MIYAMA  Yoshio MATSUDA  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E93-C   No.5   pp.685-695
Publication Date: 2010/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.685
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Integrated Electronics
Keyword: 
TCAM,  charge recycling,  low power,  low noise,  low operating current,  

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Summary: 
Architecture of a low power Ternary Content Addressable Memory (TCAM) is proposed. The TCAM is a powerful engine for search and sort processing, but it has two serious problems, large power consumption and large power line noise. To solve these problems, we have developed a charge recycling scheme for match lines and search lines. A combination of the newly introduced PMOS CAM cell together with the conventional NMOS CAM cell realizes match line charge recycling. A checkerboard arrangement of the NMOS and the PMOS cell array enables search line charge recycling. By using these technologies, the power consumption of the TCAM can be reduced to 50% of conventional designs, and as a result, the power line noise is also reduced. An experimental chip has been fabricated in 180-nm 6-metal process. The power consumption of this chip is 6.3 fJ/bit/search, which is half of the conventional scheme.