Evaluation of Surface Mount Shunt Capacitor Filters Using Bilateral Magnetic Coupling Implemented to IC Power Supply Line on PCB

This paper describes a new inductance cancellation scheme, named Bilateral Magnetic Coupling (BMC), for performance improvement of surface mount shunt capacitor filters on a PCB. A filter structure to which the BMC is applied is designed to place input/output paths parallel to the shunt path from a power supply line to a ground plane. Magnetic couplings between the input/output paths and the shunt path are utilized to reduce parasitic inductance of the shunt path. To clarify effectiveness of the BMC in actual use conditions, filters are implemented to an IC Power Supply Line on a PCB under operating conditions. As a result, the BMC scheme improves filter performance by 7.4 dB in the wide frequency band, and reduces voltage fluctuation by 37%.