Emitter coupled semiconductor memory device having a low potential source having two states

摘要

A semiconductor memory device which includes a high potential source, a low potential source, and a word line driver portion which makes the potential of selected word lines a selection level lower by a predetermined potential than the high potential source. Memory cells are connected to the word lines. A first low potential source or a second potential source is connected to the low potential source. A plurality of transistors are provided in the word line driver portion so as to connect a plurality of stages. When the memory has a sufficient power source margin, the word line driver is formed as a two-stage device so as enable high speed operation. When the memory has an unsufficient power source margin, the word line driver is formed as a one-stage device so as to ensure a sufficient power source margin.