A method for designing a device that comprises a first semiconductor chip, a second semiconductor chip and an adjustment target is disclosed. The first semiconductor chip comprises an input pad, a first power supply pad and a first ground pad. The second semiconductor chip comprises an output pad coupled to the input pad. The adjustment target is connected to the first and the second semiconductor chips. A main target variable is calculated from an input circuit chip model, an output circuit chip model of the second semiconductor chip in frequency domain and a target impedance model of the adjustment target in frequency domain. The input circuit chip model is created by representing the first semiconductor chip in frequency domain in consideration of a first capacitor model between the input pad and the first power supply pad, a second capacitor model between the input pad and the first ground pad, and a chip internal capacitor model between the first power supply pad and the first ground pad. The main target variable is compared with a predetermined constraint represented in frequency domain to decide design guidelines for the adjustment target.