A nearest-hamming-distance search memory with fully parallel mixed digital-analog match circuitry

摘要

A fully-parallel minimum Hamming-distance search memory has been designed, which uses digital circuitry for bit-comparison and fast analog circuitry for word-comparison as well as winner-take-all (WTA) functionality. The approach allows compact and high-performance integration in conventional CMOS technology. The 0.6μm, 2-poly, 3-metal CMOS design with 32 rows and 128 columns achieves 100ns search times at 260 mW power dissipation. The approach is extendable to increased pattern length and larger row numbers and enables high efficiency for pattern-matching applications such as network routers, code-book-based data compression, or object recognition. As for conventional memories high yield can be achieved with a redundancy concept for rows (including WTA function) and columns.