| 摘要 |
PURPOSE:To attain the effective access of a memory cell at the time of selecting a word line by lowering the level of a prescribed voltage from the level of the a source voltage and maintaining to a constant value. CONSTITUTION:When the potential of the end part of the word line is a zero level, the word line is non-selective. Since the level of the voltage impressed to the gate of a MIS transistor Q 1 is lower than the level of the source voltage Vcc, the gm of the transistor Q 1 is smaller than at the time of directly impressing the source voltage Vcc. Under this state, when the word line is selected and the potential of the word line is raised, the potential of the end part WL1 of the word line is rapidly elevated higher than the threshold level of a MIS transistor Q 2 to turn on the transistor Q 2 and cut off the transistor Q 1. Thereby, the potential of the end part WL1 of the word line goes to a logical high level and the memory cell in the vicinity of the end part can be effectively made access.
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