Semiconductor memory

A semiconductor memory having a plurality of cell array blocks which have dynamic memory cells arranged in rows and columns and sense amplifiers for amplifying read signals from the dynamic memory cells,

• said semiconductor memory comprising:
• a plurality of column-block select lines each shared by said plurality of cell array blocks and extending substantially in parallel with bit lines, a selected column-block select line being adapted to select a predetermined column block out of a plurality of column blocks in said plurality of cell array blocks;
• a plurality of global column select lines each disposed for a cell array block and extending in the direction which intersects said column-block select lines, a selected global column select line being adapted to simultaneously select a plurality of predetermined columns out of each of said plurality of column blocks;
• a plurality of sub data buses each shared by said plurality of cell array blocks, said sub data buses being substantially in parallel with said column-block select lines, where the number of sub data buses disposed in each column block corresponds to the number of data bits carried by the columns, in each column block, simultaneously selected by a global column select line;
• a plurality of local column selecting means respectively disposed corresponding to the positions where said plurality of column-block select lines cross said plurality of global column select lines, said plurality of local column selecting means being adapted such that the output of the local column selecting means corresponding to the position where an activated column-block select line crosses an activated global column select line, is made active;
• and
• a plurality of local column select lines connected to the output terminals of said local column selecting means, each local column select line being connected to the input terminals of column switch transistors which connect sense amplifiers, of columns selected by an associated global column select line, in a cell array block comprising the associated global column select line, and in a column block selected by an associated column-block select line, to sub data buses in the selected column-block.