A SMD-type filter solution for EMI/RFI mitigation on high-speed digital interfaces and its application

Abstract

A compact solution for filtering common-mode noise on high-speed digital interfaces is proposed and realized as a 6-pin SMD component. The component size is only 2 × 1.2 mm2. The measured common-mode suppression has a high-level rejection over 20 dB at 1.575 and 2.45 GHz, corresponding to GPS and WLAN bands. Moreover, differential-mode signals preserve well up to 10 GHz. To validate its capability, in situ experiments are demonstrated with USB 3.0 connector. Far-field and near-field emissions are indeed reduced, which implies the distances between RF antennas and high-speed connectors can be shrunk by using the proposed solution.