Fast accessible semiconductor memory device

摘要

A memory array is divided into a plurality of memory sub blocks in row and column directions. A column selection line is provided in the column direction in a region between blocks. A block decoding circuit generating a local column selection signal is arranged corresponding to each of the memory sub blocks. A main I/O line pair group is provided for each of the memory sub blocks and each column of the memory sub block is connected to the corresponding main I/O line pair in accordance with the local column selection line. Thus, data with a desired bit width can be produced without any increase in area occupied by the array nor decrease in the speed of column access.