THIN FILM TYPE COMMON MODE FILTER

摘要

The present invention relates to a thin-film common mode filter comprising: a base substrate which is composed of insulating materials; a first insulating layer formed on the base substrate; an inner electrode formed on top of the first insulating layer and forms simultaneous coil patterns that overlap along the winding direction of two coil electrodes thereon; a second insulating layer formed on the inner electrode and is formed at a height higher than the interval between the coils; an external electrode terminal which is composed of a vertical section connected at the side surface of the inner electrode and a horizontal section horizontally extended from the top end of the vertical section and forms a parallel side separated from the inner electrode; and a ferrite resin layer which receives the first and second insulating layers, and a part of the side wall of the horizontal section of the external electrode terminal. The internal electrodes of the common mode filter are manufactured in a coil electrode type, and the coil electrodes form simultaneous coil patterns that overlap along the winding direction of two coils on a layer. Also, because the height of the second insulating layer formed on top of the inner electrode is higher than the interval between the coils, it can prevent parasitic capacitance generated sites fundamentally so that it may maintain the filtering function as a common mode filter and also has an effect to increase the self-resonant frequency (SRF).