Design of an 8-nsec 72-bit-Parallel-Search Content-Addressable Memory Using a Phase-Change Device

Abstract

This paper presents a content-addressable memory (CAM) using a phase-change device. A hierarchical match-line structure and a one-hot-spot block code are indispensable to suppress the resistance ratio of the phase-change device and the area overhead of match detectors. As a result, an 8-nsec 72-bit-parallel-search CAM is implemented using a phase-change-device/MOS-hybrid circuitry, where high and low resistances are higher than 2.3MΩ and lower than 97kΩ, respectively, while maintaining one-day retention.