Patent ID: 8659327

Claim:
An output buffer applied in a semiconductor device for outputting a data signal according to an enable signal and input data, comprising: a first output transistor, comprising a first terminal coupled to a first operational voltage and a second terminal for outputting the first operational voltage as the data signal; a first switch, comprising: a first terminal coupled to a bulk of the first output transistor; and a control terminal receiving the enable signal; a second switch, comprising: first terminal coupled to a second terminal of the first switch; a control terminal receiving the enable signal; and a second terminal coupled to a second operational voltage; a third switch, comprising: a first terminal coupled to the bulk of the first output transistor; a control terminal coupled to the second terminal of the first switch; and a second terminal coupled to the first operational voltage, and a fourth switch including a first terminal coupled to the first switch and a second terminal coupled to the second switch and the fourth switch is controlled by the first operational voltage, wherein when the enable signal has a first level, the fourth switch is turned on and when the enable signal has a second level, the fourth switch is turned off.