Hermetically sealed emi feedthrough filter capacitor for human implant

Abstract

An integrated hermetically sealed feedthrough capacitor filter assembly is provided for the shielding and decoupling of a conductive terminal pin or lead of the type used, for example, in an implantable medical device such as a cardiac pacemaker or cardioverter defibrillator against passage of external interference signals, such as caused by digital cellular phones. The simplified feedthrough assembly described herein eliminates the traditional terminal pin subassembly. In this novel approach, the ceramic feedthrough capacitor itself forms a hermetic seal with a conductive pacemaker housing to which it is mounted by welding or brazing. The feedthrough capacitor is configured such that its internal electrodes are not exposed to body fluids, with capacitor electrode plate sets coupled respectively to a conductive ferrule, pin or housing (which may be grounded) and to the non-grounded, or active, terminal pin(s) by conductive adhesive, soldering, brazing, welding or the like. In one preferred form, multiple feedthrough filter capacitors are provided in a substantially coplanar array within a common base structure, with each capacitor in association with a respective terminal pin.