An IC macro model for power current analysis, called linear equivalent circuit and current source (LECCS) model, is applied to a bypass circuit design. In the bypass circuit design, since requirements to improve electromagnetic interference (EMI) and power integrity (PI) performances are becoming more and more important, improving methods are considered using the LECCS model. The LECCS model, consisting of a linear equivalent circuit and current sources, the former is closely related to EMI performance and the latter is connected to PI performance. Therefore, each idea for better performance is different. Actually examples of bypass circuits based on the idea are shown, and it is verified that the circuits work out by using a SPICE model.