US Patent 8009485 Semiconductor memory device

A semiconductor memory device includes training drivers configured to transmit one of data and a predetermined training data pattern from a first data lines to a second data lines in response to a training control signal which is produced by decoding a read training command; and the second data lines configured to transmit an output of the training drivers. The semiconductor memory device according to the present invention can exactly measure a delay time, which is changed according to the surrounding environments between a semiconductor memory device and a data processing unit, through a data training and operation timing can be also adjusted based on the measured delay time.