| 摘要 |
PURPOSE:To obtain a redundant circuit with superior substitution efficiency by increasing the number of plural selection lines connected from plural decoder output lines via plural switch devices by one or more lines over the number of plural decoder output lines at every interposition of the switch device. CONSTITUTION:In a block A, a defect exists in a second column selection line 2a in this example, and a fuse link 2a is cut off. Also, in a block B, the defect exists in an (N+1)th column selection line (N+1b), and a fuse line (N+1b) is cut off. In such a state, column selection signals 1a=Na in the block A are connected to the column selection lines 1b-Nb in the block B, and a column selection signal (N+1) in the block A is connected to the column selection line (N+2b) in the block B, and no (N+1)th selection line (N+1b) in the block B is set in a selective state. Therefore, a second selection line 2b and the (N+1)th selection line are not set in the selective state even when any column decoder output line is set in the selective state. Therefore, substitution in the blocks A, B can be performed independently. |
