Title: ZQ calibration circuit and semiconductor device comprising the same
Application Number: 200610137452 Application Date: 2006.10.25
Publication Number: 1956326 Publication Date: 2007.05.02
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03H11/28;H03K19/00;G06F13/38
Applicant(s) Name: Elpida Memory Inc. Address:
Inventor(s) Name: Nakamura Masayuki;Yoko Hideyuki
Attorney & Agent: wanghui min
Abstract:
    AZQ calibration command internally generated from an external command different from a ZQ calbration command so as to automatically perform an additional ZQ calibration operation. A command interval between an imputted command and a next command is effectively employed to obtain a ZQ calibration period. The external command different from the ZQ calibration command is preferably a self-refreshed command. The addition of the ZQ calibration operation shortens intervals between ZQ calibration operations. Thus, it is possible to obtain a ZQ calibration circuit capable of performing a ZQ calibration operation more accurately.
Time: 6