| 摘要 |
PURPOSE:To obtain a redundancy circuit which can freely arrange a fuse of a redundancy circuit at a required position and can make regulated access even after the use of a redundancy circuit. CONSTITUTION:A combination circuit 50 receives outputs QA0-QA7 in which a column address AXM is decoded by a column line decoder 2, signals QB0-QB7 indicating defective lines, signals L0-L7 generated from signals QB0-QB7, and an inverted signal ENB*, and generates a signal YS 8 from a signal YS0 which controls selective, switches designating a column line. When defect is found on the Kth column line, a column line selecting switch which selects the Kth column line is forcedly turned OFF, the (N+1)th column line is assigned for the N (>=K)th column line. Therefore, the position of the fuse of a redundancy circuit can be standardized among products, mass production of products is facilitated and products can be supplied inexpensively even if a redundancy circuit is built in ASIC of small amount and many kinds. |
