Patent ID: 7019556

Claim:
A semiconductor memory device, having ability of adjusting an output impedance of a data output driver by performing an OCD calibration control operation, comprises: a data input/output pad; a data input unit for buffering and latching a data signal inputted through the data input/output pad during a data access operation, or for buffering and latching an OCD control code signal inputted through the data input/output pad during the OCD calibration control operation; a data align unit for aligning the data signal latched by the data input unit and transferring the aligned data signal to a memory core during the data access operation, or for aligning and outputting the OCD control code signal latched by the data input unit during the OCD calibration control operation; a data output driver for outputting and driving the data signal outputted from the memory core; and an OCD control unit for decoding the OCD control code signal outputted from the data align unit to thereby adjust an output impedance of the data output driver.