Patent ID: 7944233

Claim:
A data output circuit, comprising: a pull-up driver including a plurality of pull-up resistors to pull up an output node in response to a pull-up driver control signal; a pull-down driver including a plurality of pull-down resistors to pull down the output node in response to a pull-down control signal; a pull-up controller configured to selectively transfer one of output data and a pull-up pre-emphasis enable signal according to pull-up impedance codes as the pull-up driver control signal for controlling a number of the pull-up resistors to be coupled to the output node; and a pull-down controller configured to selectively transfer one of the output data and a pull-down pre-emphasis enable signal according to pull-down impedance codes as the pull-down driver control signal for controlling a number of the pull-down resistors to be coupled to the output node.