Chip capacitor electromagnetic interference filter
First Claim
1. An electromagnetic interference (EMI) filter assembly disposed at a point of lead penetration through a conductive substrate, comprising:
- at least one conductive terminal associated with the point of lead penetration through the conductive substrate;
means for mounting the at least one conductive terminal for passage through an opening formed in the conductive substrate with the conductive terminal and the substrate in non-conductive relation; and
a plurality of chip capacitors of differing capacitance values each having first and second sets of electrode plates, the first set of electrode plates being conductively coupled to the at least one conductive terminal, and the second set of electrode plates being conductively coupled to the conductive substrate.
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Accused Products
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. In another preferred form, a non-conductive substrate is provided with metalized circuit traces to better accommodate the mounting of the chip capacitors. Additionally, novel chip capacitor geometry/termination-metallization is provided which significantly reduces the internal inductance of the capacitor to improve its high frequency performance as an EMI filter.
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Citations
20 Claims
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1. An electromagnetic interference (EMI) filter assembly disposed at a point of lead penetration through a conductive substrate, comprising:
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at least one conductive terminal associated with the point of lead penetration through the conductive substrate; means for mounting the at least one conductive terminal for passage through an opening formed in the conductive substrate with the conductive terminal and the substrate in non-conductive relation; and a plurality of chip capacitors of differing capacitance values each having first and second sets of electrode plates, the first set of electrode plates being conductively coupled to the at least one conductive terminal, and the second set of electrode plates being conductively coupled to the conductive substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electromagnetic interference (EMI) filter assembly, comprising:
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at least one conductive terminal; means for mounting the at least one conductive terminal within an opening formed in a conductive substrate, with the conductive terminal and the substrate in non-conductive relation; a first chip capacitor having first and second sets of electrode plates, wherein the first set of electrode plates is conductively coupled to the at least one conductive terminal, and the second set of electrode plates is conductively coupled to the conductive substrate; and a second chip capacitor having a capacitance value different from that of the first capacitor, the second chip capacitor having first and second sets of electrode plates, wherein the first set of electrode plates is conductively coupled to the at least one conductive terminal, and the second set of electrode plates is conductively coupled to the conductive substrate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification