CAM CAPABLE OF RESTORING COLUMN DEFECT AND COLUMN DEFECT RESTORATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a CAM (content addressable memory) capable of restoring column defects and a column defect restoration method.;SOLUTION: The CAM has a plurality of TCAM cells for storing data. Each TCAM cell has two memory cells and a comparison circuit. The comparison circuit compares data stored in the memory cells with those inputted through a pair of search lines connected to the comparison circuit and has first to fourth NMOS transistors. In the first and second NMOS transistors, the drains are linked to a match line, the gates are linked to the memory cells, and the sources are linked to the drains of the third and fourth NMOS transistors. In the third and fourth transistors, the gates are linked to the pair of search lines and the sources are linked to the ground. Defect restoration in a column direction can be facilitated by the CAM column defect restoration method and the CAM capable of restoring the column defect although only the defect restoration in a row direction has been made conventionally.;COPYRIGHT: (C)2005,JPO&NCIPI