| 摘要 |
PROBLEM TO BE SOLVED: To perform automatic refresh operation for all memory cell arrays by responding to a mode register signal generated by receiving a signal externally applied responding to plural control signals, and outputting selectively an external address externally applied and an internal address to a memory cell address array. SOLUTION: An address selector 15 selects an internal address CNTi and outputs it, thereby, word lines of main cells of a memory cell array 11 are sequentially accessed, only main cells are sequentially and automatically refreshed. Further, at the time of automatic refresh operation of a test mode, as the address selector 15 selects an external address TAiB and outputs it, word lines of main cells and word lines of spare cells can be sequentially accessed by adjusting externally the external address TAiB. Therefore, both of main cells and spare cells of the memory cell array 11 can be sequentially refreshed. |
