Design and Comparative Evaluation of a PCM-Based CAM (Content Addressable Memory) Cell

This paper presents the design of a content addressable memory (CAM) cell. This cell utilizes a phase change memory (PCM) as a storage element and an ambipolar transistor for data comparison; the operation of the ambipolar transistor is controlled by voltage at the polarity gate. A memory core consisting of a CMOS transistor and a PCM is employed (1T1P). For the search operation, the data in the 1T1P memory core are read and its values are established by using a differential sense amplifier. The proposed CAM cell is simulated and compared with other nonvolatile CAM cells by using emerging technologies (such as MTJ and memristor). The simulation results show that as the proposed CAM cell operates on a voltage basis, it offers significant advantages in terms of power delay product for the search operation and reduced circuit complexity (in terms of lower transistor and storage element counts) compared with other designs found in the technical literature.