Disclosed is a synchronous semiconductor device having a double data rate input circuit which allows data to be written in the device in response to a clock signal and a data strobe signal. The input circuit stores a pair of data which is synchronized with either the clock signal or the data strobe signal,...http://www.google.com/patents/US6078546?utm_source=gb-gplus-sharePatent US6078546 - Synchronous semiconductor memory device with double data rate scheme
