| 摘要 |
PURPOSE: An impedance control circuit is provided to prevent mismatch of a termination operation by differently setting a target impedance value of each reference impedance unit. CONSTITUTION: An impedance code generating circuit(300A) generates a pull-up impedance code and a pull-down impedance code to enable a pull-up reference impedance unit(310) and a pull-down reference impedance unit(330) to respectively have a first target impedance value and a second target impedance value. A plurality of pull-up termination units have the first target impedance value by receiving the pull-up impedance code. A plurality of pull-down termination units have the second target impedance value by receiving the pull-down impedance code. [Reference numerals] (304) Counter unit; (305) Counter unit; (306) Pull-up driver controller; (307) Pull-down driver controller |
