| 摘要 |
PROBLEM TO BE SOLVED: To refresh even when plural banks are provided with a common redundant decoder. SOLUTION: At the time of refreshing operation, each redundant decoder XRED only compares an address shown by a line address signal XADD with an address of a defective memory cell stored without referring to a bank selection signal included in the line address signal XADD. A redundant memory cell selecting circuit XRDN outputs for each bank A, B redundancy substitution selection signal XRDNS (A), (B) for showing a bank which substitutes for the redundant memory cell. Therefore, even at the time of refreshing when the banks A, B are activated at the same time, it is possible to select whether or not to substitute for each bank. |
