Data output circuit that can drive output data speedily and semiconductor memory device including such a data output circuit

Abstract

An output buffer includes a pull up transistor of N type field effect to charge a data output terminal by an external power supply potential Vdd in a high level data output operation, and a pull down transistor of N type field effect to discharge the data output terminal to a ground potential Vss in a low level data output operation. The substrate potential of the pull up NMOS transistor is set to a potential of a level higher than the normal case in a high level data output operation. As a result, the output buffer can speedily charge the data terminal in a high level data output operation.