Programmable termination circuit and method

A semiconductor device comprising:

• a plurality of termination circuits connected to a pad to perform programmable on-chip termination operations with a first impedance set at a data reception mode and to adaptively perform programmable output driving operations with a second impedance set at a data output mode;
• and
• a controller for detecting changes in characteristic impedance of a transmission line, for providing a variable program code signal to the first impedance set when the semiconductor device is in data reception mode, and for providing the variable program code signal to the second impedance set when the semiconductor device is in data output mode, wherein the impedance of the second impedance set is different from that of the first impedance set.

A semiconductor memory device to input and output data through a transmission line comprising:

• a termination circuit connected between an input/output pad and an input buffer to adaptively perform a programmable input termination function and a programmable output driving function, and to match impedance with a characteristic impedance of the transmission line in response to programmable code signals, and
• a controller for detecting changes in characteristic impedance of a transmission line, for providing the program code signals to the termination circuit to enable the data output to perform adaptively output driving operations when the semiconductor device is in data output mode, and for providing the program code signals to the termination circuit to enable the data input from outside through the input/output pad when the semiconductor device is in data reception mode.

A method for operating the data output circuit of a semiconductor device having a plurality of impedance elements connected to an input/output pad for bi-directional data transmission through a transmission line, the method comprising the steps of:

• providing a variable program code signal to the plurality of impedance elements, when the semiconductor device is in a data output mode, to enable the data output to perform adaptively output driving operations with transmission impedance of the plurality of impedance elements being matched to characteristic impedance of the transmission line;
• and
• providing the variable program code signal to the plurality of impedance elements, when the semiconductor device is in a data reception mode, to enable the data input from outside through the input/output pad to be shifted to an input buffer connected with the data output circuit with transmission impedance of the plurality of impedance elements being matched to characteristic impedance of the transmission line.