| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce power supply noise occurring in a control circuit unit that controls output buffers. <P>SOLUTION: A semiconductor device comprises: unit buffers 501 to 507 driving a data output terminal 14; impedance control circuits 511 to 513 controlling the unit buffers 501 to 507; and a control circuit unit 400 controlling the impedance control circuits 511 to 513. The impedance control circuits 511 to 513 and the control circuit unit 400 are operated by different power supplies to each other. The control circuit unit 400 supplies pull-up data and pull-down data, which are in opposite phases to each other, to the impedance control circuits 511 to 513. The impedance control circuits 511 to 513 convert the pull-up data and the pull-down data, which are in opposite phases, into the same phase and then supply them to the unit buffers 501 to 507. These features make it difficult for noise to occur in a power supply VDD used in the control circuit unit 400. <P>COPYRIGHT: (C)2012,JPO&INPIT |
