Electrical analysis and design of differential pairs used in high-speed flip-chip BGA packages

In the paper, electrical analysis and design of the differential pairs used in high-speed flip-chip ball grid array (FC-BGA) packages are presented in the frequency range up to 10 GHz. The emphases are on the critical factors that determine the overall electrical performance of the differential pairs and the related packages including impedance control and the impact of discontinuities such as via and solder ball. Manufacturing tolerance is also considered in terms of characteristic impedance. The purposes of this paper are to give an insight into electrical aspects of practical differential pairs in the FC-BGA packages to speed up high-speed packaging design.