US Patent 7385860 Data output circuit of synchronous memory device

A data output circuit of a synchronous memory device including a plurality of pipelatches having an N bits prefetch function. Each pipelatch comprises a data switching section for switching an output path of N bits data; a first data selection section for receiving one half of the N bits data and outputting the one half in response to a first control signal; a second data selection section for receiving the other half of the N bits data and outputting the other half in response to the first control signal; a first shifter for outputting a second control signal delayed by a first time after receiving the first control signal; and a second shifter for receiving the data outputted from the second data selection section and outputting the data with a delay of the first time in response to the second control signal.