Semiconductor device capable of preventing fluctuations of substrate potential

摘要

A detect circuit receives a write enable signal, a column address strobe signal and an output control signal to predetect a mode in which data is input from an input/output terminal. While a substrate potential generation circuit normally operates, a substrate potential holding circuit also operates when the detect circuit detects the mode in which data is input, so that biasing capability of a substrate potential generating portion is increased before the data is actually input from the input/output terminal.