| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor device which can be used in common in a system of a type which uses a complementary clock, and even in a system of a type which generates a 180 deg. phase clock at the inside. SOLUTION: A semiconductor device is provided with a first input circuit 11 in which a first internal clock CLK1, a second internal clock and/CLK1 in a complementary relationship are generated from an external clock and to which a first internal clock CLK is inputted so as to output the clock CLK1, a second clock input circuit 12 to which a second external clock/CLK, is inputted so as to output the second clock, a 1/2-phase-clock generation circuit 22 which generates a 1/2-phase-shift signal on the basis of the clock CLK1, an/CLK- state detection circuit 21 which judges whether/CLK, is inputted to the second clock input buffer 12 and a switch 23 which changes over the second clock so as to be output, when the second external clock/CLK is input and which changes over the 1/2-phase-shift signal so as to be output as the second internal clock/CLK1, when the clock/CLK, is not input. |
