Emi filter feedthrough having a single-sided oxide-resistant system ground opposite a system ground to an oxidized surface

Abstract

A filtered feedthrough comprises an insulator sealed in a ferrule opening. A terminal pin sealed in an insulator via hole has a first end that extends outwardly beyond an insulator device side. A filter capacitor has a square- or rectangularly-shaped dielectric supporting interleaved active and ground electrode plates. A passageway extending through the dielectric has an internal metallization. An external metallization is contacted to opposed longitudinal sides of the dielectric outer surface. The capacitor ground electrode plates extend to the opposed external metallizations. The outwardly extending terminal pin end is connected to the internal metallization in the dielectric passageway which in turn is connected to the active electrode plates. A conductive material connects the capacitor external metallization at one of the longitudinal sides to an oxide-resistant surface on the ferrule while the other external metallization is connected to an oxidized surface of the ferrule.