Patent Publication Number: US-8982532-B2

Title: Filtered feedthrough assembly and associated method

Description:
This application is a continuation of U.S. patent application Ser. No. 12/368,847, filed Feb. 10, 2009 (pending), which is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to electrical feedthroughs for implantable medical devices and, more particularly, a capacitor assembly for a filtered feedthrough. 
     INTRODUCTION 
     The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
     Electrical feedthroughs serve the purpose of providing an electrical circuit path extending from the interior of a hermetically sealed container to an external point outside the container. A conductive path is provided through the feedthrough by a conductor pin which is electrically insulated from the container. Many feedthroughs are known in the art that provide the electrical path and seal the electrical container from its ambient environment. Such feedthroughs typically include a ferrule, the conductor pin or lead and a hermetic ceramic seal which supports the pin within the ferrule. Such feedthroughs are typically used in electrical medical devices such as implantable pulse generators (IPGs). It is known that such electrical devices can, under some circumstances, be susceptible to electromagnetic interference (EMI). At certain frequencies for example, EMI can inhibit pacing in an IPG. This problem has been addressed by incorporating a capacitor structure within the feedthrough ferrule, thus shunting any EMI at the entrance to the IPG for high frequencies. This has been accomplished with the aforementioned capacitor device by combining it with the feedthrough and incorporating it directly into the feedthrough ferrule. Typically, the capacitor electrically contacts the pin lead and the ferrule. 
     Many different insulator structures and related mounting methods are known in the art for use in medical devices wherein the insulator structure also provides a hermetic seal to prevent entry of body fluids into the housing of the medical device. The feedthrough terminal pins, however, are connected to one or more lead wires which effectively act as an antenna and thus tend to collect stray or electromagnetic interference (EMI) signals for transmission to the interior of the medical device. In some prior art devices, ceramic chip capacitors are added to the internal electronics to filter and thus control the effects of such interference signals. This internal, so-called “on-board” filtering technique has potentially serious disadvantages due to intrinsic parasitic resonances of the chip capacitors and EMI radiation entering the interior of the device housing. 
     In another approach, a filter capacitor is combined directly with a terminal pin assembly to decouple interference signals to the housing of the medical device. In a typical construction, a coaxial feedthrough filter capacitor is connected to a feedthrough assembly to suppress and decouple undesired interference or noise transmission along a terminal pin. 
     So-called discoidal capacitors having two sets of electrode plates embedded in spaced relation within an insulative substrate or base typically form a ceramic monolith in such capacitors. One set of the electrode plates is electrically connected at an inner diameter surface of the discoidal structure to the conductive terminal pin utilized to pass the desired electrical signal or signals. The other or second set of electrode plates is coupled at an outer diameter surface of the discoidal capacitor to a cylindrical ferrule of conductive material, wherein the ferrule is electrically connected in turn to the conductive housing or case of the electronic instrument. 
     In operation, the discoidal capacitor permits passage of relatively low frequency electrical signals along the terminal pin, while shunting and shielding undesired interference signals of typically high frequency to the conductive housing. Feedthrough capacitors of this general type are commonly employed in implantable pacemakers, defibrillators and the like, wherein a device housing is constructed from a conductive biocompatible metal such as titanium and is electrically coupled to the feedthrough filter capacitor. The filter capacitor and terminal pin assembly prevent interference signals from entering the interior of the device housing, where such interference signals might otherwise adversely affect a desired function such as pacing or defibrillating. 
     In the past, feedthrough filter capacitors for heart pacemakers and the like have typically been constructed by preassembly of the discoidal capacitor with a terminal pin subassembly which includes the conductive terminal pin and ferrule. More specifically, the terminal pin subassembly is prefabricated to include one or more conductive terminal pins supported within the conductive ferrule by means of a hermetically sealed insulator ring or bead. See, for example, the terminal pin subassemblies disclosed in U.S. Pat. Nos. 3,920,888, 4,152,540; 4,421,947; and 4,424,551. The terminal pin subassembly thus defines a small annular space or gap disposed radially between the inner terminal pin and the outer ferrule. A small discoidal capacitor of appropriate size and shape is then installed into this annular space or gap, in conductive relation with the terminal pin and ferrule, e.g., by means of soldering or conductive adhesive. The thus-constructed feedthrough capacitor assembly is then mounted within an opening in the pacemaker housing, with the conductive ferrule in electrical and hermetically sealed relation in respect of the housing, shield or container of the medical device. 
     Although feedthrough filter capacitor assemblies of the type described above have performed in a generally satisfactory manner, the manufacture and installation of such filter capacitor assemblies has been relatively costly and difficult. One common method for forming a feedthrough filter capacitor assembly is to physically couple the capacitor to the insulating structure of the feedthrough by thermal curing of one or more non-conductive epoxy preforms. The installation of such filter capacitor assemblies poses certain problems related to the curing of the epoxy preforms. For example, the epoxy preforms may wick into the annular cavities provided between the capacitor and the terminal pins during curing and thus occupy space that should be filled by a conductive material (e.g., epoxy, solder). This results in a degraded electrical connection between the terminal pins and the capacitors. Additionally, the non-conductive epoxy preforms may seep into the insulating structure and cover cracks that have formed through the braze joint. This may prevent gas from being detected during leak testing and, therefore, may create the impression that a satisfactory hermetic seal has been formed when, in fact, one has not. The use of non-conductive epoxy has been considered mandatory not only because of the physical coupling of the capacitor to the insulating structure, but also because the non-conductive epoxy, when cured, prevents the seeping of conductive material, which is used to electrically couple the capacitor to the pin and ferrule, into the insulating structure of the feedthrough. 
     The present teachings provide a feedthrough filter capacitor assembly of the type used, for example, in implantable medical devices such as heart pacemakers and the like, wherein the filter capacitor is designed for relatively simplified and economical, yet highly reliable, installation. Further, the present teachings provide a filtered feedthrough assembly utilizing an improved capacitor attachment technique that eliminates the need for non-conductive epoxy and prevents the undesired travel of conductive material, such as epoxy or solder. 
     SUMMARY 
     In various exemplary embodiments, the present disclosure relates to a filtered feedthrough assembly comprising a ferrule, a capacitor, at least one terminal pin and a support structure. The capacitor comprises a top portion, a bottom portion, and an inner diameter portion. The inner diameter portion of the capacitor defines at least one aperture extending from the top portion to the bottom portion. The at least one terminal pin extends through the at least one aperture. The support structure is configured to be received within the ferrule, and comprises at least one projection extending from a first side. The at least one projection comprises an inner circumference defining an opening extending through the support structure to a second side opposing the first side. The at least one projection extends into the at least one aperture of the capacitor and the at least one terminal pin extends through the opening. 
     In various exemplary embodiments, the present disclosure relates to a method of assembling a filtered feedthrough assembly comprising inserting at least one terminal pin, a support structure and a capacitor within a ferrule. The support structure comprises at least one projection extending from a first side, the at least one projection comprising an inner circumference defining an opening extending through the support structure to a second side opposing the first side. The capacitor comprises a top portion, a bottom portion, and an inner diameter portion. The inner diameter portion defines at least one aperture extending from the top portion to the bottom portion. The at least one projection extends into the at least one aperture of the capacitor. The at least one terminal pin extends through the opening and through the at least one aperture. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIGS. 1 and 2  are isometric and cross-sectional views, respectively, of a known unipolar (single pin) feedthrough assembly prior to attachment of a discrete discoidal capacitor; 
         FIGS. 3-5  illustrate a prior art method of attaching a discrete discoidal capacitor to the feedthrough assembly shown in  FIGS. 1 and 2 ; 
         FIG. 6  is a cross-sectional view of a unipolar (single pin) filtered feedthrough assembly according to various exemplary embodiments of the present disclosure prior to attachment of a discrete discoidal capacitor; 
         FIG. 7  is a cross-sectional view of a unipolar (single pin) filtered feedthrough assembly with an attached discrete discoidal capacitor according to various exemplary embodiments of the present disclosure; 
         FIG. 8A  is a perspective side view of a support structure utilized in a unipolar (single pin) filtered feedthrough assembly according to various embodiments of the present disclosure; 
         FIG. 8B  is a cross-sectional view of the support structure of  FIG. 8A  taken along line B-B; 
         FIG. 9A  is a perspective side view of a support structure utilized in a multipolar (multiple pin) filtered feedthrough assembly according to various embodiments of the present disclosure; 
         FIG. 9B  is a perspective top view of the support structure of  FIG. 9A ; 
         FIG. 9C  is a cross-sectional view of the support structure of  FIGS. 9A and 9B  taken along line C-C; 
         FIG. 10  is an exploded view of a multipolar (multiple pin) filtered feedthrough assembly illustrating the attachment of a monolithic discoidal capacitor in accordance with various exemplary embodiments of the present disclosure; 
         FIG. 11  is a perspective view of a partially disassembled implantable medical device; and 
         FIG. 12  is an isometric cutaway view of an implantable medical device incorporating the multipolar (multiple pin) filtered feedthrough assembly of  FIG. 10 . 
     
    
    
     DESCRIPTION 
     The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure. 
       FIGS. 1 and 2  are isometric and cross-sectional views, respectively, of a known unipolar (single pin) feedthrough assembly  100  having a terminal pin  102  extending therethrough. Assembly  100  comprises a generally cylindrical ferrule  104  having a cavity through which pin  102  passes. Ferrule  104  is made of an electrically conductive material (e.g., titanium alloy) and is configured to be fixedly coupled (e.g., welded) to the container of a medical device as described below in conjunction with  FIG. 11-12 . An insulating structure  106  is disposed within ferrule  104  to secure pin  102  relative to ferrule  104  and to electrically isolate pin  102  from ferrule  104 . Insulating structure  106  comprises a supporting structure  108  and a joint-insulator sub-assembly  110 , both of which are disposed around terminal pin  102 . As will be more fully described below, joint-insulator sub-assembly  110  acts as an insulative seal and may take the form of, for example, a braze joint. Supporting structure  108  is made of a non-conductive material (e.g., polyimide) and rests on an inner ledge  112  provided within ferrule  104 . As will be seen in  FIG. 3 , a discrete discoidal capacitor  150  may be threaded over terminal pin  102  and fixedly coupled to supporting structure  108  to attach the capacitor to feedthrough assembly  100 . 
     As can be seen in  FIG. 2 , braze joint  110  comprises three main components: an insulator ring  114  (e.g., made from a ceramic material) that insulates pin  102  from ferrule  104 , a pin-insulator braze  116  (e.g., made from gold) that couples insulating ring  114  to pin  102 , and an insulator-ferrule braze  118  (e.g., made from gold) that couples insulating ring  114  to ferrule  104 . Braze joint  110  is exposed along the underside of ferrule  104 . When ferrule  104  is fixedly coupled to the container of the medical device, the lower portion of ferrule  104 , and thus the lower portion of braze joint  110 , may be exposed to body fluids. For this reason, it is important that braze joint  110  forms a hermetic seal between ferrule  104  and terminal pin  102 . Braze joint  110  may be leak tested. To permit this test to be performed, an aperture  120  ( FIG. 1 ) is provided through ferrule  104  to the inner annular cavity formed by the outer surface of braze joint  110 , the lower surface of supporting structure  108 , and the inner surface of ferrule  104 . A gas is delivered through aperture  120  into the inner annular cavity, and aperture  120  is plugged. Preferably, a gas of low molecular weight (e.g., helium or hydrogen) is chosen so that it may easily penetrate small cracks in braze joint  110 . Feedthrough  100  is then monitored for the presence of the gas proximate braze joint  110  by way of, for example, a mass spectrometer. If no gas is detected, it is concluded that braze joint  110  has formed a satisfactory seal. 
     Terminal pin  102  provides a conductive path from the interior of a medical device (not shown) to one or more lead wires exterior to the medical device. As described previously, these lead wires are known to act as antennae that collect stray electromagnetic interference (EMI) signals, which may interfere with the proper operation of the device. To suppress and/or transfer such EMI signals to the container of the medical device, a discrete discoidal capacitor may be attached to feedthrough assembly  100 . In particular, the capacitor may be disposed around and electrically coupled to terminal pin  102  and fixedly coupled to supporting structure  108 .  FIGS. 3-5  illustrate a known manner of attaching a discrete discoidal capacitor  150  to feedthrough assembly  100  shown in  FIGS. 1 and 2 . The attachment method commences as a ring-shaped preform  152  of non-conductive epoxy is threaded over terminal pin  102  (indicated in  FIG. 3  by arrow  154 ). Capacitor  150  is then threaded over pin  102  and positioned against preform  152  such that preform  152  is sandwiched between capacitor  150  and supporting structure  108 . Next, feedthrough assembly  100  is placed within a curing oven and heated to a predetermined temperature (e.g., approximately 175 degrees Celsius) to thermally cure preform  152  (indicated in  FIG. 4  by arrows  156 ) and thus physically couple capacitor  150  to supporting structure  108 . 
     During curing, preform  152  melts and disperses under the weight of capacitor  150 , which moves downward toward supporting structure  108 . Preform  152  disperses along the annular space provided between the bottom surface of capacitor  150  and the upper surface of supporting structure  108  to physically couple capacitor  150  and supporting structure  108  as described above. In addition, preform  152  may disperse upward into the annular space provided between the inner surface of capacitor  150  and outer surface of terminal pin  102  (shown in  FIG. 5  at  158 ). Dispersal of preform  152  in this manner may interfere with the proper electrical coupling of capacitor  150  to terminal pin  102 . Also, during curing, preform  152  may disperse downward into insulating structure  110  (shown in  FIG. 5  at  160 ). This dispersal may result in preform  152  covering any cracks that have formed through braze joint  110  and, consequently, prevent the accurate leak testing of feedthrough assembly  100 . 
     Referring now to  FIGS. 6-7 , a filtered feedthrough assembly  200  according to various exemplary embodiments of the present disclosure is illustrated. Filtered feedthrough assembly  200  is unipolar (single pin) and has a terminal pin  202  extending therethrough. Assembly  200  comprises a generally cylindrical ferrule  204  having a cavity through which pin  202  passes. Ferrule  204  is made of an electrically conductive material (e.g., titanium alloy) and is configured to be fixedly coupled (e.g., welded) to the container of a medical device as described below in conjunction with  FIGS. 11-12 . An insulating structure comprising supporting structure  280  and a joint-insulator sub-assembly  210  is disposed within ferrule  204  to secure pin  202  relative to ferrule  204  and to electrically isolate pin  202  from ferrule  204 . Both of the supporting structure  280  and a joint-insulator sub-assembly  210  are disposed around terminal pin  202 . The joint-insulator sub-assembly  210  acts as an insulative seal and may take the form of, for example, a braze joint. As described more fully below, supporting structure  280  is made of a non-conductive material (e.g., polyimide, polyetheretherketone (PEEK) or similar material) and rests on an inner ledge  212  provided within ferrule  204 . As will be seen, a discrete discoidal capacitor may be threaded over terminal pin  202  and fixedly coupled to supporting structure  280  to attach the capacitor to feedthrough assembly  200 . 
     Braze joint  210  comprises three main components: an insulator ring  214  (e.g., made from a ceramic material) that insulates pin  202  from ferrule  204 , a pin-insulator braze  216  (e.g., made from gold) that couples insulating ring  214  to pin  202 , and an insulator-ferrule braze  218  (e.g., made from gold) that couples insulating ring  214  to ferrule  204 . Braze joint  210  is exposed along the underside of ferrule  204 . When ferrule  204  is fixedly coupled to the container of the medical device, the lower portion of ferrule  204 , and thus the lower portion of braze joint  210 , may be exposed to body fluids. For this reason, it is important that braze joint  210  forms a hermetic seal between ferrule  204  and terminal pin  202 , which may be leak tested, as described above. 
     Terminal pin  202  provides a conductive path from the interior of a medical device (not shown) to one or more lead wires exterior to the medical device. As described previously, these lead wires are known to act as antennae that collect stray electromagnetic interference (EMI) signals, which may interfere with the proper operation of the device. To suppress and/or transfer such EMI signals to the container of the medical device, a discrete discoidal capacitor  250  may be attached to feedthrough assembly  200 . In particular, the capacitor  250  may be disposed around and electrically coupled to terminal pin  202  and fixedly coupled to supporting structure  280 , described more fully below. 
     The capacitor  250  includes a top portion  252 , a bottom portion  254 , an inner diameter portion  256  and an outer diameter portion  258 . The inner diameter portion  256  defines an aperture  255 , extending from the top portion  252  to the bottom portion  254 , through which the terminal pin  202  extends. In the assembled filtered feedthrough assembly  200 , the inner diameter portion  256  of capacitor  250  is electrically coupled to the terminal pin  202 , e.g., by means of solder or conductive epoxy  257 . Similarly, the outer diameter portion  258  of capacitor  250  is electrically coupled to the ferrule  204 , e.g., by means of solder or conductive epoxy  259 . The inner and outer diameters  256 ,  258  are each electrically coupled with one of the two sets of electrode plates that are electrically isolated from one another and form the capacitor  250 . 
     Referring now to  FIGS. 6-9C , a support structure  280  according to various exemplary embodiments of the present disclosure is illustrated. As shown in  FIGS. 6-7 , support structure  280  is sized and configured to be received within ferrule  204 . In the illustrated example, support structure rests upon an inner ledge  212  provided within ferrule  204 . As shown in  FIGS. 8A-9C , support structure  280  may be designed for use in a unipolar, i.e., single pin, feedthrough assembly as shown in  FIGS. 8A-B , or a multipolar, i.e., multiple pin, feedthrough assembly as shown in  FIGS. 9A-C . The design differences between a unipolar and multipolar support structure  280  are minor and essentially equate to including the correct number of openings within support structure  280  to accommodate the number of terminal pin(s)  202  in the feedthrough. 
     The support structure  280  comprises at least one projection  281  extending from a first side  282  of the support structure  280 . The inner circumference  284  of the projection  281  defines an opening  285  that extends through the support structure  280  from the first side  282  to a second side  283  opposed thereto. In some exemplary embodiments, the projection  281  includes a cylindrical base portion  286  and a chamfered portion  287 . The chamfered portion  287  simplifies insertion of the projection  281  into the aperture  255  of the capacitor  250 , as described more fully below. 
     The opening  285  is sized to receive and mate with terminal pin  202 . In some exemplary embodiments, the opening  285  is sized such that the terminal pin  202  is tightly secured in the opening  285 , e.g., to create a seal between terminal pin  202  and opening  285 . In the exemplary embodiment illustrated in  FIGS. 9A-C , the projection  281  is comprised of a bifurcated cylindrical base portion, which is, in its simplest form, a cylindrical projection  281  that is split in two, or more, portions. The split allows for elastic deformation of the projection  281  such that the outer diameter of terminal pin  202  may be greater than the inner circumference  284  of opening  285  in a non-deformed state. Upon insertion of terminal pin  202  into opening  285 , the portions of the projection  281  expand outwardly to accommodate the terminal pin  202 , while the resiliency of the projection  281  portions provides a force upon terminal pin  202  to assist in the securing and sealing of the terminal pin  202  in opening  285 . Additionally, the walls of the opening  285  may be substantially straight, as shown in  FIGS. 8A-B , or otherwise contoured, e.g., tapered to provide a conical cross-section as shown in  FIGS. 9A-C , to assist in the insertion of terminal pin  202  into the opening  285 . 
     The filtered feedthrough assembly  200  according to various exemplary embodiments may be assembled as follows. The joint-insulator sub-assembly  210  is disposed within ferrule  204  to secure pin  202  relative to ferrule  204  and to electrically isolate pin  202  from ferrule  204 , as described more fully above. Support structure  280  may then be inserted within ferrule  204  such that terminal pin  202  extends through opening  285 . As described above, the opening  285  of support structure  280  may be sized so as to mate with terminal pin  202  in a secure fashion. A partially assembled filtered feedthrough assembly  200  according to various exemplary embodiments of the present disclosure is illustrated in  FIG. 6 . 
     Capacitor  250  is then inserted at least partially within the ferrule  204  such that terminal pin  202  extends through, and the projection  281  is partially received within, aperture  255 . In some exemplary embodiments, projection  281  and aperture  255  are sized such that the projection  281  is tightly secured in the aperture  255 , e.g., to create a seal between projection  281  and aperture  255 . In this manner, support structure  280  may be physically coupled to capacitor  250  without the use of non-conductive epoxy or other compound as in the prior art, which not only simplifies the assembly process, but also prevents the intrusion of the non-conductive epoxy into the joint-insulator sub-assembly  210 . Furthermore, projection  281  may be sized and positioned such that the terminal pin  202  is substantially centered within aperture  255 , which will assist in the formation of a reliable electrical connection between capacitor  250  and terminal pin  202 . 
     After placement of capacitor  250  within ferrule  204 , the inner diameter portion  256  of capacitor  250  is electrically coupled to the terminal pin  202 , e.g., by means of solder or conductive epoxy  257 . Similarly, the outer diameter portion  258  of capacitor  250  is electrically coupled to the ferrule  204 , e.g., by means of solder or conductive epoxy  259 . Support structure  280 , and specifically the coupling of aperture  255  and projection  281 , inhibits or prevents the flow of solder or conductive epoxy  257 ,  259  into the joint-insulator sub-assembly  210 . A fully assembled filtered feedthrough assembly  200  according to various exemplary embodiments of the present disclosure is illustrated in  FIG. 7 . 
       FIG. 10  illustrates the attachment of a monolithic discoidal capacitor  300  to a multipolar feedthrough assembly  302  in accordance with a various exemplary embodiments of the present invention. Filtered feedthrough assembly  302  comprises a ferrule  306  and an insulating structure  304  disposed within ferrule  306 . Filtered feedthrough assembly  302  guides an array of terminal pins  305  through the container of a medical device to which ferrule  304  is coupled (shown in  FIG. 12 ). As described above, terminal pin array  305  and the lead wires to which array  305  is coupled may act as an antenna and collect undesirable EMI signals. Monolithic discoidal capacitor  300  may be attached to feedthrough assembly  302  to provide EMI filtering. Capacitor  300  is provided with a plurality of terminal pin-receiving apertures  310  therethrough. Capacitor  300  is inserted over terminal pin array  305  such that each pin in array  305  is received by a different aperture  310  and placed in an abutting relationship with insulating structure  304 . If desired, one terminal pin in array  305  may be left unfiltered as shown in  FIG. 10  to serve as an RF antenna. Support structure  380  is provided between insulating structure  304  and capacitor  300 . Capacitor  300  may be coupled to support structure  380 , such as by projections  381  on support structure  380  being securely received within terminal pin-receiving apertures  310 , similarly to that discussed above in regard to a unipolar feedthrough assembly  200 . Furthermore, a sleeve  382  may be included on support structure  380  to assist in the isolation of the unfiltered pin  305 U from capacitor  300 . 
       FIG. 11  is an exploded view of an implantable medical device (e.g., a pulse generator)  350  coupled to a connector block  351  and a lead  352  by way of an extension  354 . The proximal portion of extension  354  comprises a connector  356  configured to be received or plugged into connector block  351 , and the distal end of extension  354  likewise comprises a connector  358  including internal electrical contacts  360  configured to receive the proximal end of lead  352  having electrical contacts  362  thereon. The distal end of lead  352  includes distal electrodes  364 , which may deliver electrical pulses to target areas in a patient&#39;s body (or sense signals generated in the patient&#39;s body, e.g., cardiac signals). 
     After a capacitor  300  has been attached to feedthrough assembly  302  in the manner described above, assembly  302  may be welded to the housing of an implantable medical device  350  as shown in  FIG. 12 . Medical device  350  comprises a container  352  (e.g. titanium or other biocompatible material) having an aperture  354  therein through which feedthrough assembly  302  is disposed. As can be seen, each terminal pin in array  305  has been trimmed and is electrically connected to circuitry  356  of device  350  via a plurality of connective wires  358  (e.g., gold), which may be coupled to terminal pin array  305  by wire bonding, laser ribbon bonding, or the like. After installation, feedthrough assembly  302  and capacitor  300  collectively function to permit the transmission of relatively low frequency electrical signals along the terminal pins in array  305  to circuitry  356  while shunting undesired high frequency EMI signals to container  352  of device  350 . 
     The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims.