Patent ID: 8106676

Claim:
A semiconductor device, comprising: a signal generating circuit that generates an impedance adjustment command signal which indicates at least one of initiation and termination of an impedance adjustment; and an impedance adjusting circuit that performs an impedance adjustment based on the impedance adjustment command signal from the signal generating circuit, wherein the semiconductor device outputs an output signal in synchronism with the impedance adjustment command signal, the impedance adjusting circuit generates a driver code which changes a driver size of the output buffer, the impedance adjusting circuit supplies the driver code to an output buffer, and the signal generating circuit causes the impedance adjustment command signal to be transitioned from a first logic level to a second logic level, so as to activate the impedance adjusting circuit, the signal generating circuit causes the impedance adjustment command signal to be transitioned from the second logic level to the first logic level, in response to a driver code generation termination signal given by the impedance adjusting circuit.