Associative IC memories with relational search and nearest-match capabilities

The authors present the design and implementation of content addressable memories (CAMs) that execute relational and nearest-match instructions. Implementation of a novel relational search cell is presented. Direct performance comparison shows an order-of-magnitude improvement over existing designs with similar cell area. The design and implementation of a neural-inspired nearest-match CAM using a winner-take-all (WTA) network is presented. An original approach to analyzing such neural-inspired CAMs is presented. A model which describes the behavior of the WTA network is derived to be utilized in the design and performance prediction of the network. Performance of the WTA network in differentiating between words with large bit mismatches is analyzed, and an upper bound is set. Fully functional prototype chips have been fabricated through MOSIS using 2- mu m double-metal CMOS technology. Theoretical, simulation, and physical chip measurements are in good agreement.<
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