Patent Publication Number: US-2022224052-A1

Title: Contact assembly with ground bus

Description:
BACKGROUND OF THE INVENTION 
     The subject matter herein relates generally to electrical connectors. 
     Electrical connectors are typically used to electrically couple various types of electrical devices to transmit signals between the devices. At least some known electrical connectors include a cable assembly having cables connected between the electrical device and the electrical connector. The cables each have a signal conductor or a differential pair of signal conductors surrounded by a shield layer that, in turn, is surrounded by a cable jacket. The shield layer includes a conductive foil, which functions to shield the signal conductor(s) from electromagnetic interference (EMI) and generally improve performance. At an end of the communication cable, the cable jacket, the shield layer, and insulation that covers the signal conductor(s) may be removed (e.g., stripped) to expose the signal conductor(s). The exposed portions of the conductor(s) may then be mechanically and electrically coupled (e.g., soldered) to corresponding elements of an electrical device. However, the lack of shielding in the exposed portions may cause a high impedance mismatch and reduce the overall performance of the device. 
     Accordingly, there is a need for an electrical connector having improved electrical shielding. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a contact assembly for an electrical connector is provided. The electrical connector includes a leadframe having an array of contacts include signal contacts and ground contacts. The ground contacts are interspersed with the signal contacts to provide electrical shielding between corresponding signal contacts. Each signal contact includes a signal intermediate portion extending between a signal mating end and a signal terminating end. Each ground contact includes a ground intermediate portion extending between a ground mating end and a ground terminating end. The ground terminating end has a leadframe ground bus connecting each of the ground contacts. The electrical connector includes a contact holder holding the array of contacts. The contact holder is a dielectric material. The contact holder holds each of the signal intermediate portions and holds each of the ground intermediate portions. The signal mating ends, and the ground mating ends extend forward of the contact holder. The signal terminating ends and the ground terminating ends extending rearward of the contact holder. The electrical connector includes cables terminated to the leadframe. The cables include signal conductors and ground shields surrounding the corresponding signal conductors to provide electrical shielding for the signal conductors. The signal conductors are terminated to corresponding signal terminating ends. The leadframe ground bus are terminated to each of the ground shields to electrically common the ground shields and the leadframe ground bus. The electrical connector includes an external ground bus separate and discrete from the leadframe ground bus. The external ground bus are terminated to each of the ground shields at an opposite side of the cables from the leadframe ground bus to electrically common the ground shields and the external ground bus. 
     In a further embodiment, a contact assembly for an electrical connector is provided. The electrical connector includes a leadframe having an array of contacts including signal contacts and ground contacts. The signal contacts are arranged in pairs. The ground contacts interspersed between the pairs of the signal contacts to provide electrical shielding between the corresponding signal contacts. Each signal contact includes a signal intermediate portion extending between a signal mating end and a signal terminating end. Each ground contact includes a ground intermediate portion extending between a ground mating end and a ground terminating end. The ground terminating end has a leadframe ground bus connecting each of the ground contacts. The leadframe ground bus include connecting portions between the ground contacts. The electrical connector includes a contact holder holding the array of contacts. The contact holder is a dielectric material. The contact holder holds each of the signal intermediate portions and holds each of the ground intermediate portions. The signal mating ends, and the ground mating ends extend forward of the contact holder. The signal terminating ends and the ground terminating ends extend rearward of the contact holder. The electrical connector includes cables terminated to the leadframe. The cables include signal conductors and ground shields surrounding the corresponding signal conductors to provide electrical shielding for the signal conductors. The signal conductors are terminated to corresponding signal terminating ends. The connecting portions of the leadframe ground bus are aligned with the cables and are terminated to the ground shields of the corresponding cables to electrically common the ground shields and the leadframe ground bus. The electrical connector includes an external ground bus separate and discrete from the leadframe ground bus. The external ground bus has ground beams and connecting portions between the ground beams. The ground beams are aligned with and coupled to the corresponding ground contacts. The connecting portions of the external ground bus are aligned with the cables and are terminated to the ground shields of the corresponding cables at an opposite side of the cables from the leadframe ground bus. The external ground bus electrically commoning the ground shields and the external ground bus. 
     In a further embodiment, an electrical connector is provided. The electrical connector includes a housing has a cavity receiving an upper contact assembly and a lower contact assembly. The housing includes a card slot at a mating end of the housing configured to receive a card edge of a circuit card of a mating connector. The upper contact assembly includes an upper leadframe having an array of upper contacts including upper signal contacts and upper ground contacts. The upper ground contacts are interspersed with the upper signal contacts to provide electrical shielding between corresponding upper signal contacts. Each upper signal contact includes an upper signal intermediate portion extending between an upper signal mating end and an upper signal terminating end. Each upper ground contact includes an upper ground intermediate portion extending between an upper ground mating end and an upper ground terminating end. The upper ground terminating end has an upper leadframe ground bus connecting each of the upper ground contacts. The upper signal mating ends and the upper ground mating ends located in the card slot for mating with the circuit card. The upper contact assembly includes an upper contact holder holding the array of upper contacts. The upper contact holder is a dielectric material. The upper contact holder holding each of the upper signal intermediate portions and holding each of the upper ground intermediate portions. The upper signal mating ends and the upper ground mating ends extend forward of the upper contact holder. The upper signal terminating ends and the upper ground terminating ends extend rearward of the upper contact holder. The upper contact assembly includes upper cables terminated to the upper leadframe. The upper cables include upper signal conductors and upper ground shields surrounding the corresponding upper signal conductors to provide electrical shielding for the upper signal conductors. The upper signal conductors are terminated to corresponding upper signal terminating ends. The upper leadframe ground bus are terminated to each of the upper ground shields to electrically common the upper ground shields and the upper leadframe ground bus. The upper contact assembly includes an upper external ground bus separate and discrete from the upper leadframe ground bus. The upper external ground bus are terminated to each of the upper ground shields at an opposite side of the upper cables from the upper leadframe ground bus to electrically common the upper ground shields and the upper external ground bus. The lower contact assembly includes a lower leadframe having an array of lower contacts including lower signal contacts and lower ground contacts. The lower ground contacts are interspersed with the lower signal contacts to provide electrical shielding between corresponding lower signal contacts. Each lower signal contact includes a lower signal intermediate portion extending between a lower signal mating end and a lower signal terminating end. Each lower ground contact includes a lower ground intermediate portion extending between a lower ground mating end and a lower ground terminating end. The lower ground terminating end has a lower leadframe ground bus connecting each of the lower ground contacts. The lower signal mating ends and the lower ground mating ends located in the card slot for mating with the circuit card. The lower contact assembly includes a lower contact holder holding the array of lower contacts. The lower contact holder is coupled to the upper contact holder. The lower contact holder is a dielectric material. The lower contact holder holding each of the lower signal intermediate portions and holding each of the lower ground intermediate portions. The lower signal mating ends and the lower ground mating ends extending forward of the lower contact holder. The lower signal terminating ends and the lower ground terminating ends extending rearward of the lower contact holder. The lower contact assembly includes lower cables terminated to the lower leadframe. The lower cables include lower signal conductors and lower ground shields surrounding the corresponding lower signal conductors to provide electrical shielding for the lower signal conductors. The lower signal conductors are terminated to corresponding lower signal terminating ends. The lower leadframe ground bus are terminated to each of the lower ground shields to electrically common the lower ground shields and the lower leadframe ground bus. The lower contact assembly includes a lower external ground bus separate and discrete from the lower leadframe ground bus. The lower external ground bus are terminated to each of the lower ground shields at an opposite side of the lower cables from the lower leadframe ground bus to electrically common the lower ground shields and the lower external ground bus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical connector formed in accordance with one embodiment. 
         FIG. 2  is a perspective view of an electrical connector formed in accordance with one embodiment. 
         FIG. 3  is a perspective view of a contact assembly of the formed in accordance with one embodiment. 
         FIG. 4  is a side view of the contact assembly in accordance with an exemplary embodiment. 
         FIG. 5  is a side view of the contact assembly in accordance with an exemplary embodiment. 
         FIG. 6  is a top view of the contact assembly in accordance with an exemplary embodiment. 
         FIG. 7  is a bottom view of the contact assembly in accordance with an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of an electrical connector  10  formed in accordance with one embodiment. The electrical connector  10  is configured to be mated with a mating electrical connector  30 . In an exemplary embodiment, the electrical connector  10  has a mating end  20 , a cable end  22 , and one or more cables  24  extending from the cable end  22 . The electrical connector  10  includes a housing  26  configured to hold a contact assembly  100 . In an exemplary embodiment, the housing  26  includes a card slot  28  at the mating end  20 . In the illustrated embodiment, the electrical connector  10  is a communication device, such as a serial attached SCSI (SAS) connector. However, the electrical connector  10  may be another type of electrical connector in an alternative embodiment. For example, the electrical connector  10  may define a socket or receptacle connector, such as a card edge socket connector. 
     The mating electrical connector  30  is configured to be mated with the electrical connector  10 . In an exemplary embodiment, the mating electrical connector  30  has a circuit card  32  at a mating end  34  of the mating electrical connector  30 . The circuit card  32  includes mating contacts  36  at a card edge  38  of the circuit card  32 . The connectors  10 ,  30  may be a high-speed connectors that transmit data signals at speeds over 10 gigabits per second (Gbps), such as over 25 Gbps. The connectors  10 ,  30  may be input-output (I/O) connectors. 
       FIG. 2  is a perspective view of an electrical connector  50  formed in accordance with one embodiment. The electrical connector  50  is configured to be mated with a mating electrical connector  70 . In an exemplary embodiment, the electrical connector  50  has a mating end  60 , a cable end  62 , and one or more cables  64  extending from the cable end  62 . The electrical connector  50  includes a housing  66  configured to hold the contact assembly  100 . In an exemplary embodiment, the housing  66  includes a card slot  68  at the mating end  60 . In an exemplary embodiment, the mating electrical connector  70  has a circuit card  72  at a mating end  74  of the mating electrical connector  70 . The circuit card  72  includes mating contacts  76  at a card edge  78  of the circuit card  72 . 
       FIG. 3  is a perspective view of the contact assembly  100  formed in accordance with one embodiment. In an exemplary embodiment, the contact assembly  100  includes an upper contact subassembly  102  and a lower contact subassembly  104  coupled to a frame  106 . The frame  106  supports the upper and lower contact subassemblies  102 ,  104 . Optionally, the upper and lower contact subassemblies  102 ,  104  may be identical to each other and inverted 180°. In alternative embodiments, the contact assembly  100  may be provided without the frame  106 , rather having the upper and lower contact assemblies coupled directly to each other without an intervening supporting structure. In other alternative embodiments, the contact assembly  100  may be provided with a single contact subassembly, such as provided without the lower contact subassembly  104 . 
     The description herein may be made specifically to the “upper” contact subassembly  102  with the qualifier “upper” and may be made specifically to the “lower” contact subassembly  104  with the qualifier “lower” or may be made generically to the upper or the lower contact subassemblies  102 ,  104  without use of the qualifiers “upper” or “lower”. The contact assembly  100  includes a leadframe  110  having an array of contacts  112  including signal contacts  114  and ground contacts  116 . The contact assembly  100  includes a contact holder  120  holding the array of contacts  112 . The contact assembly  100  includes cables  122  terminated to the leadframe  110 . The contact assembly  100  includes an external ground bus  124  provided to electrically common the ground contacts  116  and the cables  122 . 
     The contact holder  120  is used to hold the contacts  112 , including the signal contacts  114  and the ground contacts  116 . The contact holder  120  is manufactured from a dielectric material to electrically isolate the contacts  112  from each other. In an exemplary embodiment, the contact holder  120  is overmolded over the leadframe  110  to encase portions of the contacts  112  and hold relative positions of the contacts  112 . The contact holder  120  extends between a front  126  and a rear  128 . 
     In an exemplary embodiment, the contacts  112  are arranged in one or more rows. For example, the upper contacts  112  are arranged in an upper row configured to interface with an upper surface of a circuit card, such as the circuit card  32 , and the lower contacts  112  are arranged in a lower row configured to interface with a lower surface of the circuit card. In an exemplary embodiment, the signal contacts  114  are arranged in pairs, such as differential pairs. The ground contacts  116  are interspersed between the signal contacts  114 , such as between the pairs of the signal contacts  114 , to provide electrical shielding between the corresponding signal contacts  114 . 
     Each signal contact  114  includes a signal intermediate portion  130  extending between a signal mating end  132  and a signal terminating end  134 . The contact holder  120  holds the signal intermediate portions  130  relative to each other. The contact holder  120  maintains spacing between the signal contacts  114 . The signal mating ends  132  are located forward of the contact holder  120 . The signal terminating ends  134  are located rearward of the contact holder  120 . In an exemplary embodiment, the signal contacts  114  include spring beams  136  at the signal mating ends  132 . The spring beams  136  are deflectable spring beams. The spring beams  136  include separable mating interfaces at or near the distal ends of the spring beams  136 . The spring beams  136  may be curved or cupped at the distal ends to prevent stubbing during mating with the circuit card. In an exemplary embodiment, the signal contacts  114  include weld pads  138  at the signal terminating ends  134 . The weld pads  138  are configured to be welded to conductors of the cables  122 . 
     Each ground contact  116  includes a ground intermediate portion  140  extending between a ground mating end  142  and a ground terminating end  144 . The contact holder  120  holds the ground intermediate portions  140  relative to each other and relative to the signal intermediate portions  130 . The ground mating ends  142  are located forward of the contact holder  120 . The ground terminating ends  144  are located rearward of the contact holder  120 . In an exemplary embodiment, the ground contacts  116  include spring beams  146  at the ground mating ends  142 . The spring beams  146  are deflectable spring beams. The spring beams  146  include separable mating interfaces at or near the distal ends of the spring beams  146 . The spring beams  146  may be curved or cupped at the distal ends to prevent stubbing during mating with the circuit card. In an exemplary embodiment, the ground contacts  116  include a leadframe ground bus  150  (shown in  FIG. 4 ) at the ground terminating ends  144 . The leadframe ground bus  150  electrically commons each of the ground contacts  116  with the cables  122  and with each other. The leadframe ground bus  150  is separate and discrete from the external ground bus  124 . 
     During assembly, the upper and lower contact subassemblies  102 ,  104  are coupled to the frame  106 . The frame  106  includes a platform  200  at a front of the frame  106 . The upper and lower contact holders  120  are coupled to the platform  200 , such as to upper and lower surfaces of the platform  200 , respectively. The frame  106  includes a cable support tray  202  rearward of the platform  200 . The cable support tray  202  supports the cables  122 , such as along upper and lower surfaces of the cable support tray  202 . The cable support tray  202  includes separating walls  204  forming cable channels  206  that receive corresponding cables  122 . In an exemplary embodiment, the frame  106  includes a strain relief element  208  providing strain relief for the cables  122 . The strain relief element  208  is coupled to the cable support tray  202 . During assembly, the cables  122  are received in the cable channels  206  and terminated to the leadframe  110 . Signal conductors  210  (shown in  FIG. 4 ) of the cables  122  are terminated to the signal contacts  114 . The external ground bus  124  and the leadframe ground bus  150  are terminated to ground shields  212  of the cables  122 . 
     The external ground bus  124  is separate and discrete from the leadframe ground bus  150 . Both the external ground bus  124  and the leadframe ground bus  150  are electrically connected to the ground shields  212  of the cables  122  to electrically common the ground shields  212 . In an exemplary embodiment, the external ground bus  124  and the leadframe ground bus  150  are coupled to opposite sides of the ground shields  212  of the cables  122  to provide shielding both above and below the cables  122 . The external ground bus  124  includes ground fingers  160  and connecting portions  162  between the ground fingers  160 . The ground fingers  160  are aligned with and coupled to the corresponding ground contacts  116 . The connecting portions  162  are aligned with the cables  122  and terminated to the ground shields  212  of the corresponding cables  122  at an opposite side of the cables  122  from the leadframe ground bus  150 . The external ground bus  124  electrically commons each of the ground shields  212 . The external ground bus  124  is coupled to the ground contacts  116  to electrically common the external ground bus  124  with the leadframe ground bus  150 . In an exemplary embodiment, the external ground bus  124  includes a connecting beam  164  extending between and connecting each of the ground fingers  160 . The connecting beam  164  commons each of the ground fingers  160 . The connecting beam  164  is spaced apart from the connecting portions  162 . The connecting beam  164  may span across each of the ground fingers  160 , such as at the front of the external ground bus  124 . The connecting beam  164  may abut against the contact holder  120  to position the external ground bus  124  relative to the contact holder  120 . The connecting beam  164  may extend generally perpendicular relative to the ground fingers  160 . For example, the connecting beam  164  may extend vertically and the ground fingers  160  may extend horizontally. 
       FIG. 4  is a side view of the contact assembly  100  in accordance with an exemplary embodiment.  FIG. 4  illustrates the upper and lower contact subassemblies  102 ,  104  coupled to the frame  106 . The contact holders  120  are coupled to the frame  106 . The upper signal contacts  114  and the upper ground contacts  116  are aligned with each other in an upper row and the lower signal contacts  114  and the lower ground contacts  116  are aligned with each other in a lower row. For example, the signal and ground mating ends  132 ,  142  are aligned with each other. The signal and ground intermediate portions  130 ,  140  are aligned with each other. The leadframe ground bus  150  at the ground terminating end  144  extends out of plane relative to the signal terminating ends  134 . 
     In an exemplary embodiment, the cable  122  is located between the external ground bus  124  and the leadframe ground bus  150 . The cable  122  may be sandwiched between the external ground bus  124  and the leadframe ground bus  150 . The external ground bus  124  and the leadframe ground bus  150  are both electrically coupled to the ground shield  212 . For example, the external ground bus  124  and the leadframe ground bus  150  may be soldered to the ground shield  212 . The external ground bus  124  and the leadframe ground bus  150  provide multiple points of contact with the ground shield  212 . Electrical shielding is provided both above and below the ground shield  212  to enhance shielding and electrical performance of the electrical connector  10 . In the illustrated embodiment, the upper external ground bus  124  extends above the cable  122  and is coupled to a top side of the cable  122  and the upper leadframe ground bus  150  extends below the cable and is coupled to a bottom side of the cable  122 . In the illustrated embodiment, the lower leadframe ground bus  150  extends above the cable  122  and is coupled to a top side of the cable  122  and the lower external ground bus  124  extends below the cable and is coupled to a bottom side of the cable  122 . 
     The ground finger  160  is provided at the front of the external ground bus  124  and extends along the ground contact  116 , such as along the ground intermediate portion  140 . The ground finger  160  is electrically coupled to the ground contact  116 . For example, the ground finger  160  may be welded to the ground contact  116 . The electrical connection between the ground finger  160  and the ground contact  116  provides separate points of contact. 
       FIG. 5  is a side view of the contact assembly  100  in accordance with an exemplary embodiment.  FIG. 5  illustrates the upper and lower contact subassemblies  102 ,  104  coupled to the frame  106 . In the illustrated embodiment, the external ground bus  124  and the leadframe ground bus  150  are inverted relative to the orientation shown in the embodiment shown in  FIG. 4 . In the illustrated embodiment, the upper leadframe ground bus  150  extends above the cable  122  and is coupled to a top side of the cable  122  and the upper external ground bus  124  extends below the cable and is coupled to a bottom side of the cable  122 . In the illustrated embodiment, the lower external ground bus  124  extends above the cable  122  and is coupled to a top side of the cable  122  and the lower leadframe ground bus  150  extends below the cable and is coupled to a bottom side of the cable  122 . 
       FIG. 6  is a top view of the contact assembly  100  in accordance with an exemplary embodiment.  FIG. 7  is a bottom view of the contact assembly  100  in accordance with an exemplary embodiment. The contact holders  120  hold the contacts  122  relative to each other. The external ground bus  124  ( FIG. 6 ) and the leadframe ground bus  150  ( FIG. 7 ) are coupled to the ground shields  212  of each of the cables  122 . For example, the external ground bus  124  is soldered to the top sides of the ground shields  212  to mechanically and electrically connect the external ground bus  124  to the ground shields  212 . The leadframe ground bus  150  is soldered to the bottom sides of the ground shields  212  to mechanically and electrically connect the leadframe ground bus  150  to the ground shields  212 . Having the external ground bus  124  and the leadframe ground bus  150  enhances electrical performance of the electrical connector  10 . For example, the shielding on both sides of the cables  122  improves broadband cross talk. 
     In an exemplary embodiment, the connecting portions  162  ( FIG. 6 ) of the external ground bus  124  are aligned with and coupled to the ground shields  212 . Connecting portions  152  ( FIG. 7 ) of the leadframe ground bus  150 , which extend between the ground contacts  116 , are aligned with and coupled to the ground shields  212 . The connecting portions  152 ,  162  may be soldered to the ground shields  212 . With reference to  FIG. 6 , the connecting beam  164  extends between the ground fingers  160  to common each of the ground fingers  160 . The connecting beam  164  is spaced apart from the connecting portions  162 . With reference to  FIG. 7 , the ground contacts  116  extend forward from the leadframe ground bus  150 . The ground contacts  116  are located between the signal contacts  114 . 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.