Filtered feedthrough assembly having an MLCC filter capacitor on an AIMD circuit board attached to the ferrule of a hermetic feedthrough
View Patent ↗An EMI/energy dissipating filter for an active implantable medical device (AIMD) is described. The filter comprises a first gold braze hermetically sealing the insulator to a ferrule that is configured to be mounted in an opening in a housing for the AIMD. A lead wire is hermetically sealed in a passageway through the insulator by a second gold braze. A circuit board substrate is disposed adjacent the insulator. A two-terminal chip capacitor disposed adjacent to the circuit board has an active end metallization that is electrically connected to the active electrode plates and a ground end metallization that is electrically connected to the at least one ground electrode plates of the chip capacitor. There is a ground path electrically extending between the ground end metallization of the chip capacitor and the ferrule. The ground path comprises at least a first electrical connection material connected directly to the first gold braze, and at least an internal ground plate disposed within the circuit board substrate with the internal ground plate being electrically connected to both the first electrical connection material and the ground end metallization of the chip capacitor. An active path electrically extends between the active end metallization of the chip capacitor and the lead wire.
1. A filtered feedthrough assembly for an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
a) a ferrule configured to be attached to an opening in a metal housing of an AIMD;
b) an electrical insulator hermetically sealed to the ferrule by a first gold braze;
c) at least one conductive lead wire extending through and hermetically sealed to the insulator by a second gold braze;
d) a circuit board comprising at least one circuit board ground plate and at least two circuit board ground vias traversing and electrically connected to the at least one circuit board ground plate;
e) an MLCC capacitor comprising an MLCC capacitor ground termination and an MLCC capacitor active termination, wherein the MLCC capacitor ground termination is electrically connected to the at least one circuit board ground plate through a first one of the at least two circuit board ground vias, and wherein the MLCC capacitor active termination is electrically connected to the at least one lead wire extending through and hermetically sealed to the insulator; and
f) an electrical connection material directly electrically connecting a second one of the at least two circuit board ground vias electrically connected to the at least one circuit board ground plate to the first gold braze hermetically sealing the insulator to the ferrule.
2. The filtered feedthrough assembly of claim 1 , wherein the electrical connection material is selected from the group of a conductive epoxy, a conductive polyimide, a conductive solder, and combinations thereof.
3. The filtered feedthrough assembly of claim 1 , wherein the circuit board includes a plurality of circuit board ground plates, and wherein the at least two circuit board ground vias traverse and are electrically connected to the plurality of circuit board ground plates.
4. The filtered feedthrough assembly of claim 3 , wherein the plurality of circuit board ground plates are electrically connected to each other by at least a third circuit board ground via, and wherein the third circuit board ground via is not the first one of the at least two circuit board ground vias electrically connecting the MLCC capacitor ground termination of the MLCC capacitor to the plurality of circuit board ground plates, and is not the second one of the at least two circuit board ground vias electrically connecting the first gold braze to the plurality of circuit board ground plates.
5. The filtered feedthrough assembly of claim 1 , wherein the electrical connection material directly electrically connecting the first gold braze to the second one of the at least two circuit board ground vias electrically connected to the at least one circuit board ground plate is at least one of a conductive epoxy, a conductive polyimide, and a conductive solder, and wherein the electrical connection material is disposed within the second one of the at least two circuit board ground vias.
6. The filtered feedthrough assembly of claim 1 , wherein the circuit board has an edge metallization that is electrically connected to the at least one circuit board ground plate and to the first gold braze hermetically sealing the insulator to the ferrule.
7. The filtered feedthrough assembly of claim 1 , wherein the second one of the at least two circuit board ground vias is spatially aligned along an axis with the first gold braze.
8. A filtered feedthrough assembly for an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
a) a ferrule configured to be attached to an opening in a metal housing of an AIMD;
b) an electrical insulator hermetically sealed to the ferrule by a first gold braze;
c) a plurality of conductive lead wires extending through the insulator and being hermetically sealed to the insulator by respective second gold brazes;
d) a circuit board disposed adjacent to the second side of the insulator, the circuit board including a plurality of circuit board ground plates and a plurality of circuit board ground vias traversing and electrically connected to the plurality of circuit board ground plates, the plurality of ground vias thereby providing a plurality of electrically conductive paths through the plurality of circuit board ground plates;
e) a plurality of MLCC capacitors, each MLCC capacitor having an MLCC capacitor ground termination and an MLCC capacitor active termination, wherein the MLCC capacitor ground termination of each MLCC capacitor is electrically connected to the plurality of circuit board ground plates through a respective first one of the plurality of circuit board ground vias, and wherein the MLCC capacitor active termination corresponding to the MLCC capacitor ground termination of each MLCC capacitor is electrically connected to one of the plurality of lead wires extending through and hermetically sealed to the insulator by the respective second gold brazes; and
f) an electrical connection material directly electrically connecting a second one of the plurality of circuit board ground vias electrically connected to the plurality of circuit board ground plates and corresponding to each of the plurality of MLCC capacitors to the first gold braze hermetically sealing the insulator to the ferrule.
9. The filtered feedthrough assembly of claim 8 , wherein the electrical connection material directly electrically connecting the first gold braze to the second one of the plurality of circuit board ground vias corresponding to each of the plurality of MLCC capacitors is at least one of a conductive epoxy, a conductive polyimide, and a conductive solder, and wherein the electrical connection material is disposed within the second one of the plurality of circuit board ground vias.
10. The filtered feedthrough assembly of claim 8 , wherein the second one of the plurality of circuit board ground vias is spatially aligned along an axis with the first gold braze.
11. A filtered feedthrough assembly for an active implantable medical device (AIMD), filtered feedthrough assembly comprising:
a) a ferrule configured to be attached to an opening in a metal housing of an AIMD;
b) an electrical insulator hermetically sealed to the ferrule by a first gold braze;
c) a conductive lead wire extending through and hermetically sealed to the insulator by a second gold braze;
d) a circuit board disposed adjacent to or connected to at least one of the ferrule and the insulator, the circuit board including at least one circuit board ground plate and at least two circuit board ground vias traversing and electrically connected to the at least one circuit board ground plate; and
e) at least one MLCC capacitor having an MLCC capacitor ground termination and an MLCC capacitor active termination, wherein the MLCC capacitor ground termination is electrically connected to the at least one circuit board ground plate through a first one of the at least two ground vias, and wherein an electrical connection material directly electrically connects a second one of the at least two circuit board ground vias electrically connected to the at least one circuit board ground plate to the first gold braze, the second one of the at least two circuit board ground vias being spatially aligned along an axis with the first gold braze, and
f) wherein the active termination of the MLCC capacitor is electrically connected to the conductive lead wire extending through and hermetically sealed to the insulator.