US Patent 10491215 Calibration circuit and calibration apparatus including the same

A calibration circuit sharing a resistor for impedance matching includes a command decoder configured to receive a command signal and decode the command signal into a calibration enable signal; a selector configured to select one of the calibration enable signal and a start signal according to a select signal, and provide a driving signal; and a calibration driver configured to perform an impedance matching operation in response to the driving signal, and generate a completion signal when performance is completed, wherein the start signal corresponds to a completion signal provided from another calibration circuit which shares the resistor for the impedance matching.