MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a memory device which can read out data at high speed and can perform mask operation at the time of a burst writing mode. SOLUTION: This memory device has the constitution in which a logic circuit by an input/output mask signal DQM is eliminated from a critical path to a pre-decoder and a column decoder from a clock CLK for generating a column selecting signal CL. The logic circuit is eliminated and a time required from supply of a clock to generation of a column selecting signal is shortened as much as possible. On the other hand, drive control of a writing amplifier is performed based on an input/output mask signal DQM to enable an input/output masking at the time of a burst writing mode. That is, the activation of the writing amplifier is prohibited or permitted by responding to the input/output mask signal DQM. Or, in a direct sense type sense amplifier, the generation of a writing column selecting signal is prohibited in accordance with the input/ output mask signal DQM. A logic of the input/output mask signal DQM is not inserted to generate a read-out column selecting signal.