| 摘要 |
<p>PURPOSE: To prevent redundant cell array area from increasing by controlling access to a normal column according to a select signal selecting the column corresponding to a redunancy sense signal. CONSTITUTION: A normal column decoder NCD and a redundant column decoder RCD are provided and a defective normal memory cell is substituted for by a spare cell. At this time, a block selecting circuit BLS generates a block select signal for selecting a specific block corresponding to a row address RA. A redundancy sense circuit generates the redundancy sense signal actuating the substitution for the spare cell according to a column address matching a fuse circuit and the said block select signal. Then a redundancy selecting circuit RS selects a column to be replaced corresponding to the sense signal. Then a normal decoder control circuit NCD controls access to the normal column decoder NCD according to the redundancy signal, so redundant cell arrays RCA are prevented from increasing.</p> |
