Single-Sided Or Single-Ended System Ground For A Rectangular Or Square AIMD EMI Filter Capacitor

A hermetically sealed filtered feedthrough for an active implantable medical device (AIMD), the filtered feedthrough comprising:

• a) an electrically conductive ferrule comprising a ferrule opening extending to a ferrule device side spaced from a ferrule body fluid side;
• b) an electrically non-conductive insulator comprising an insulator outer surface extending to an insulator device side spaced from an insulator body fluid side, wherein the insulator disposed in the ferrule opening is hermetically sealed to the ferrule by a first gold braze so that when the ferrule is attached to an opening in a housing of an AIMD, the ferrule and insulator body fluid sides, and the ferrule and insulator device sides reside outside and inside the AIMD, respectively, and wherein at least two insulator via holes extend to the insulator device and body fluid sides;
• c) an insulator metallization disposed in the two insulator via holes;
• d) first and second terminal pins residing in a respective one of the at least two insulator via holes where a second gold braze hermetically seals the terminal pin to the insulator metallization, wherein the first and second terminal pins extend to a terminal pin first end spaced from a terminal pin second end, and wherein at least the first and second terminal pin first ends extend outwardly beyond the insulator device side;
• e) a filter capacitor disposed at or adjacent to the insulator device side, the filter capacitor comprising:
• i) a capacitor dielectric comprising a dielectric outer surface extending to a dielectric first major face spaced from a dielectric second major face, wherein, in plan view looking at the dielectric first major face, the capacitor dielectric has a rectangular shape comprising opposed dielectric first and second long sides extending to and meeting with opposed dielectric third and fourth short ends;
• ii) at least one active electrode plate and at least one ground electrode plate supported in the capacitor dielectric in an interleaved, partially overlapping capacitive relationship;
• iii) first and second dielectric passageways in the capacitor dielectric;
• iv) a capacitor internal metallization disposed in the first and second dielectric passageways, wherein the at least one active electrode plate is connected to the capacitor internal metallization in the first and second dielectric passageways, and wherein the outwardly extending first and second terminal pin first ends reside in the respective first and second dielectric passageways where the terminal pin is conductively connected to the capacitor internal metallization connected to the at least one active electrode plate by a first conductive material, and wherein the at least one ground electrode plate is in a non-conductive relation with the capacitor internal metallization in the dielectric passageway;
• and
• v) a capacitor external metallization disposed on a terminated dielectric outer surface portion, but not on an unterminated dielectric outer surface portion of the dielectric outer surface, wherein the at least one ground electrode plate extends to the dielectric first long side comprising the terminated dielectric outer surface portion, but the ground electrode plate does not extend to the second long side comprising the unterminated dielectric outer surface portion of the capacitor dielectric so that the at least one ground electrode plate is conductively connected to the capacitor external metallization at the terminated dielectric outer surface portion, and wherein the at least one active electrode plate is in a non-conductive relation with the capacitor external metallization;
• and
• f) a second conductive material connecting the capacitor external metallization at the terminated dielectric outer surface portion to a gold bond pad supported on the ferrule device side or to the first braze sealing the insulator to the ferrule to provide a system ground for the filtered feedthrough.

A hermetically sealed filtered feedthrough for an active implantable medical device (AIMD), the filtered feedthrough comprising:

• a) an electrically conductive ferrule comprising a ferrule opening extending to a ferrule device side spaced from a ferrule body fluid side;
• b) an electrically non-conductive insulator comprising an insulator outer surface extending to an insulator device side spaced from an insulator body fluid side, wherein the insulator disposed in the ferrule opening is hermetically sealed to the ferrule by a first gold braze so that when the ferrule is attached to an opening in a housing of an AIMD, the ferrule and insulator body fluid sides, and the ferrule and insulator device sides reside outside and inside the AIMD, respectively, and wherein at least two insulator via holes extend to the insulator device and body fluid sides;
• c) an insulator metallization disposed in the two insulator via holes;
• d) first and second terminal pins residing in a respective one of the at least two insulator via holes where a second gold braze hermetically seals the terminal pin to the insulator metallization, wherein the first and second terminal pins extend to a terminal pin first end spaced from a terminal pin second end, and wherein at least the first and second terminal pin first ends extend outwardly beyond the insulator device side;
• e) a filter capacitor disposed at or adjacent to the insulator device side, the filter capacitor comprising:
• i) a capacitor dielectric comprising a dielectric outer surface extending to a dielectric first major face spaced from a dielectric second major face;
• ii) at least one active electrode plate and at least one ground electrode plate supported in the capacitor dielectric in an interleaved, partially overlapping capacitive relationship;
• iii) first and second dielectric passageways in the capacitor dielectric;
• iv) a capacitor internal metallization disposed in the first and second dielectric passageway passageways, wherein the at least one active electrode plate is connected to the capacitor internal metallization in the first and second dielectric passageways, and wherein the outwardly extending first and second terminal pin first ends reside in the respective first and second dielectric passageways where the terminal pins are conductively connected to the capacitor internal metallization connected to the at least one active electrode plate by a first conductive material, and wherein the at least one ground electrode plate is in a non-conductive relation with the capacitor internal metallization in the first and second dielectric passageways;
• and
• v) a capacitor external metallization disposed on at least a portion of the dielectric outer surface to provide a terminated dielectric outer surface portion comprising first and second segments of the terminated dielectric outer surface portion, wherein the at least one ground electrode plate extends to the first segment of the terminated dielectric outer surface portion, but the at least one ground electrode plate does not extend to the second segment of the terminated dielectric outer surface portion, and wherein the at least one active electrode plate is in a non-conductive relation with the capacitor external metallization;
• and
• f) a second conductive material connecting the first segment of the terminated dielectric outer surface portion to a gold bond pad supported on the ferrule device side or to the first braze sealing the insulator to the ferrule to provide a system ground for the filtered feedthrough.