Abstract: A process for manufacturing an EMI filter feedthrough terminal assembly is provided for mating a feedthrough filter capacitor with an hermetic terminal assembly including a ferrule and one or more lead wires which extend through the ferrule in non-conductive relation. The process includes the steps of placing the hermetic terminal assembly, having a capture flange, into a holding fixture, and forming a seat of non-conductive thermal-setting material onto the terminal assembly within the capture flange. A feedthrough filter capacitor is loaded into the capture flange on top of the seat, and then the seat is cured. A conductive thermal-setting material is dispensed between an outer diameter of the feedthrough filter capacitor and the capture flange. The assembly is then centrifuged to pack the conductive thermal-setting material. The conductive thermal-setting material is then cured between the outer diameter of the feedthrough filter capacitor and the capture flange.

Abstract: A feedthrough filter capacitor assembly for use in active implantable medical devices and a related process for manufacturing a monolithic ceramic capacitor utilizing dielectric materials having a dielectric constant greater than 7000, and preferably in the range of 8500 to 22,000. In the manufacture of the monolithic ceramic capacitor, one or more Curie point shifters and/or other dopants are added to the dielectric material to optimize the dielectric constant at the human body temperature of 37° C. For manufacturing purposes, dopants may be added to the dielectric material to broaden the Curie point peak or point of maximum dielectric constant thereof. The effect is that when such capacitors and terminal assemblies are utilized in a high-voltage defibrillator circuit of an implantable medical device, the dielectric material is optimized so that during the delivery of high-voltage electrical energy, capacitance value of the capacitor drops substantially.

Abstract: In a feedthrough terminal assembly, a guard electrode plate is disposed within the ceramic casing and adjacent to a surface of an electromagnetic interference (EMI) filter capacitor for reducing electromagnetic field stress on that surface. In a related process, the ground electrode plate is optimized utilizing computer generated electrostatic field modeling. The guard electrode plate may be grounded, either to external capacitor surface metallization or internal capacitor surface metallization. Alternatively, the guard electrode plate may float within the casing in a manner where it is electrically isolated from both the active and ground sets of electrode plates of the EMI filter capacitor. A second guard electrode plate may also be disposed within the casing adjacent to an opposite axial surface of the capacitor casing for reducing electromagnetic field stress on that adjacent surface of the casing.

Abstract: A feedthrough filter capacitor assembly for use in active implantable medical devices and a related process for manufacturing a monolithic ceramic capacitor utilizing dielectric materials having a dielectric constant greater than 7000, and preferably in the range of 8500 to 22,000. In the manufacture of the monolithic ceramic capacitor, one or more Curie point shifters and/or other dopants are added to the dielectric material to optimize the dielectric constant at the human body temperature of 37° C. For manufacturing purposes, dopants may be added to the dielectric material to broaden the Curie point peak or point of maximum dielectric constant thereof. The effect is that when such capacitors and terminal assemblies are utilized in a high-voltage defibrillator circuit of an implantable medical device, the dielectric material is optimized so that during the delivery of high-voltage electrical energy, capacitance value of the capacitor drops substantially.

Abstract: An EMI filter feedthrough terminal assembly includes at least one conductive terminal pin, a feedthrough filter capacitor which has a passageway through which the terminal pin extends, and a conductive substrate through which the terminal pin passes in non-conductive relation. The conductive substrate includes a capture flange having a height that is less than an axial thickness of the capacitor and which is configured to at least partially surround an outer periphery of the capacitor. The height of the capture flange is preferably one-quarter to three-quarters of the axial thickness of the capacitor. A first set of capacitor electrodeplates is conductively coupled to the terminal pin, and a second set of electrode plates is conductively coupled to the capture flange by means of a thermal-setting conductive material disposed between the outer periphery of the capacitor and the capture flange.

Abstract: An EMI filter feedthrough terminal assembly includes at least one conductive terminal pin, a feedthrough filter capacitor which has a passageway through which the terminal pin extends, and a conductive substrate through which the terminal pin passes in non-conductive relation. The conductive substrate includes a capture flange having a height that is less than an axial thickness of the capacitor and which is configured to at least partially surround an outer periphery of the capacitor. The height of the capture flange is preferably one-quarter to three-quarters of the axial thickness of the capacitor. A first set of capacitor electrodeplates is conductively coupled to the terminal pin, and a second set of electrode plates is conductively coupled to the capture flange by means of a thermal-setting conductive material disposed between the outer periphery of the capacitor and the capture flange.

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.

Abstract: An electromagnetic interference (EMI) filter capacitor assembly is provided for shielding and decoupling a conductive terminal pin or lead of the type used, for example, in an implantable medical device against passage of external interference signals. The EMI filter is constructed of relatively inexpensive ceramic chip capacitors which replace relatively expensive feedthrough capacitors as found in the prior art. The chip capacitors are mounted directly onto a hermetic feedthrough terminal in groups of two or more which vary in physical size, dielectric material and capacitance value so that they self-resonate at different frequencies. This "staggering" of resonant frequencies and direct installation at the hermetic terminal provides the EMI filter with sufficient broadband frequency attenuation. In one preferred form, multiple chip capacitor groupings are mounted onto a common base structure, with each capacitor grouping associated with a respective terminal pin.

Abstract: An electromagnetic interference (EMI) filter capacitor assembly is provided for shielding and decoupling a conductive terminal pin or lead of the type used, for example, in an implantable medical device against passage of external interference signals. The EMI filter is constructed of relatively inexpensive ceramic chip capacitors which replace relatively expensive feedthrough capacitors as found in the prior art. The chip capacitors are mounted directly onto a hermetic feedthrough terminal in groups of two or more which vary in physical size, dielectric material and capacitance value so that they self-resonate at different frequencies. This "staggering" of resonant frequencies and direct installation at the hermetic terminal provides the EMI filter with sufficient broadband frequency attenuation. In one preferred form, multiple chip capacitor groupings are mounted onto a common base structure, with each capacitor grouping associated with a respective terminal pin.