Patent ID: 6483400
Filing Date: 2002-11-19
Classification: H03H

Abstract:
A passive low pass filter of a surface mount device configuration comprising:a first coil having a top winding, a bottom winding, and a first centerline, the first coil wound about the first centerline; a second coil having a top winding, a bottom winding, and a second centerline, the second coil wound about the second centerline, the first centerline parallel to the second centerline, the top winding of the first coil attached to the top winding of the second coil, the first coil being counter-wound with respect to the second coil; at least one capacitor disposed adjacent to the first or second coil, each capacitor having a plurality of hot plates and at least one ground plate, the plurality of hot plates and the at least one ground plate stacked alternately and disposed perpendicular to the first and second centerlines, the plurality of hot plates having a feed plate, the bottom windings contacted electrically with the feed plate, wherein the at least one capacitor comprises a first capacitor, the first coil disposed between the first capacitor and the second coil, and a second capacitor, the second coil disposed between the second capacitor and the first coil, the bottom windings of the first and second coils connected to the feed plates of the first and second capacitors, respectively; and a dielectric encapsulant encasing the first and second coils and each one of the at least one ground plate and each one of the plurality of hot plates of the at least one capacitor, each one of the at least one ground plate and each one of the plurality of hot plates being exposed through the dielectric encapsulant, the ground plates being interconnected via a ground conductor plate, and the hot plates being interconnected via a hot conductor plate; wherein the first and second coils each having at least one intermediate winding and a plurality of vias, the intermediate winding disposed between the top and bottom windings, the vias engaged electrically between the top, intermediate and bottom windings, each successive via offset circumferentially about the centerline so as not to short circuit the windings, each top, bottom and intermediate winding coplanar with one of the ground plates or one of the hot plates of the first and second capacitors, and; the dielectric encapsulant having a plurality of layers perpendicular to the first and second centerlines, the plurality of layers having: a bottom combination layer containing the feed plates of the first and second capacitors and the bottom windings of the first and second coils, the feed plate of the fist capacitor contacting the bottom winding of the first coil, the feed plate of the second capacitor contacting the bottom winding of the second coil, a top combination layer having the top winding of the first coil, the top winding of the second coil, one of the hot plates of the first capacitor and one of the hot plates of the second capacitor, at least one ground combination layer each having one of the intermediate windings of the first coil, one of the intermediate windings of the second coil, one of the ground plates of the first capacitor and one of the ground plates of the second capacitor, and a plurality of via layers each having one via of the first coil and one via of the second coil, the dielectric encapsulant of the via layers disposed between the hot plates and the ground plates.