Race-Free Mixed Serial-Parallel Comparison for Low Power Content Addressable Memory

Seong-Ook JUNG  Sei-Seung YOON  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E91-A   No.3   pp.895-898
Publication Date: 2008/03/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e91-a.3.895
Print ISSN: 0916-8508
Type of Manuscript: LETTER
Category: VLSI Design Technology and CAD
Keyword: 
content addressable memory,  high speed,  low power,  serial CAM,  parallel CAM,  hybrid CAM,  

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Summary: 
This letter presents a race-free mixed serial-parallel comparison (RFMSPC) scheme which uses both serial and parallel CAMs in a match line. A self-reset search line scheme for the serial CAM is proposed to avoid the timing race problem and additional timing penalties. Various 32 entry CAMs are designed using 90 nm 1.2 V CMOS process to verify the proposed RFMSPC scheme. It shows that the RFMSPC saves power consumption by 40%, 53% and 63% at the cost of a 4%, 6% and 16% increase in search time according to 1, 2, and 4 serial CAM bits in a match line.