| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem that an error is generated between a delay time in a DQ buffer system and a delay time in a DQ replica system due to variations etc. in temperature, voltage, and manufacturing in a conventional DLL circuit. <P>SOLUTION: A delay amount variable circuit for varying delay amount by a result of ZQ calibration is configured to be inserted into a path of the DQ replica system. The delay amount of the path of the DQ replica system is variable, and to be adjusted so that difference in timing skew between the DQ buffer system and the DQ replica system becomes constant. Since the result of the ZQ calibration is varied in response to the variations etc. in temperature, voltage, and manufacturing variation, a DLL circuit having high accuracy capable of providing constant skew difference by acquiring the delay amount corresponding to these variations, and a semiconductor device providing the DLL circuit can be acquired. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
