Impedance controllable output driving circuit in semiconductor device and impedance control method therefore

摘要

An impedance controllable output driving circuit in a semiconductor device and an impedance control method are provided to obtain reliability from first data transmission by preventing an impedance matching error generated in a period having data transition. In an impedance controllable output driving circuit in a semiconductor device, an array unit for impedance matching includes a plurality of transistors outputting output data of which impedance is updated through an output pad(30) by being selectively driven according to a state of an array driving control signal generated by applied control code data. An update prohibition control unit generates a control signal which forbids the plurality of transistors to be driven during a certain time period when a state of inner data transits, and applies the control signal to the array unit for impedance matching, wherein the inner data becomes source data of the output data.