In a read operation, for example, 32 sense amplifiers read 32 pieces of data
in
a group. After that, the read data is outputted on a 4-bit unit basis. A memory
cell array operates at a low frequency which is of an actual data output
frequency. On the other hand, in a write operation, data is transferred from the
outside to a semiconductor memory device bit by bit every cycle. Consequently,
by providing a number of latches of a pipeline in a write access path, the writing
operation is enabled even at a high frequency. Specifically, at the time of reading,
a memory array operates at a low frequency which is of a data output frequency.
At the time of writing, data is written every clock.
