CLOCK-FREE MODE REGISTER SETTING METHOD AND DEVICE USING THE SAME

A method and an apparatus for setting a clock free mode register are provided to freely set the mode register at a clock frequency, by avoiding limitation on own operation frequency of an MRS(Mode Register Set) even if the operation frequency of a synchronous semiconductor memory device increases. In an apparatus for setting a mode register of a semiconductor device, an MRS entry time determining circuit(41) determines a mode register setting time by judging whether a first control signal received to a first input pin of the semiconductor device maintains a first level for a predetermined time during initialization of the semiconductor device. A mode register setting control circuit(42) outputs a mode register setting control signal in a period of the transition of a second control signal received to a second input pin of the semiconductor device, in response to an MRS entry detection signal outputted from the MRS entry time determining circuit. The second clock signal can be shifted during a longer period than the period of a clock signal.