[0001] The invention relates to electrical connectors that are mounted on circuit boards.

[0002] To meet digital multi-media demands, higher data throughput is often desired for current digital communications equipment. Electrical connectors that interconnect circuit boards must therefore handle ever increasing signal speeds at ever increasing signal densities. However, at the footprints of the circuit boards where the electrical connectors connect thereto it may be difficult to improve density while maintaining electrical performance and/or reasonable manufacturing cost. For example, vias within the circuit boards must be large enough to plate for a given circuit board thickness, but must also be far enough apart from one another to maintain electrical performance (e.g., impedance and/or noise). To increase the number of vias, and therefore increase the density of the circuit board footprint, the vias must be smaller and/or closer together. However, moving the vias closer together degrades the electrical performance of the circuit board footprint, while decreasing the size of the vias may increase manufacturing costs by increasing the difficulty of plating the vias. Circuit board footprints are currently the bottleneck for achieving higher system densities and/or higher system speeds.

[0003] Different known approaches have been used to improve the electrical performance and/or density of circuit board footprints. For example, careful via placement, anti-pad optimization, and counter boring of via stubs have been used to improve circuit board footprints. However, to achieve higher system densities and speed, further improvement of circuit board footprints must be made over known approaches.

[0004] There is a need for an electrical connector that enables improvement of the density and/or electrical performance of circuit board footprints to achieve higher system densities and/or higher system speeds.

[0005] This problem is solved by an electrical connector according to claim 1.

[0006] According to the invention, an electrical connector is configured for mounting on a circuit board having first and second vias. The electrical connector comprises a housing having a mounting face for mounting along the circuit board, and first and second signal terminals held by the housing. The first and second signal terminals comprise respective first and second mounting contacts extending outward from the mounting face of the housing. The first and second mounting contacts are configured to be received within the first and second vias, respectively, of the circuit board. The first and second mounting contacts extend respective different first and second lengths from the mounting face of the housing.

[0007] The invention will now be described by way of example with reference to the accompanying drawings wherein:

[0008] Figure 1 is a cross-sectional view of an exemplary embodiment of an electrical connector assembly.

[0009] Figure 2 is a perspective view of an exemplary embodiment of a receptacle connector of the electrical connector assembly shown in Figure 1.

[0010] Figure 3 is another perspective view of the receptacle connector shown in Figure 2.

[0011] Figure 4 is a cross-sectional view of a portion of the electrical connector assembly shown in Figure 1.

[0012] Figure 5 is a perspective view of an exemplary embodiment of a header connector of the electrical connector assembly shown in Figure 1.

[0013] Figure 6 is a cross-sectional view of a portion of the electrical connector assembly shown in Figure 1.

[0014] Figure 1 is a cross-sectional view of an exemplary embodiment of an electrical connector assembly 10. The connector assembly 10 includes a pair of circuit boards 12 and 14, a receptacle connector 16, and a header connector 18. The receptacle connector 16 is mounted on the circuit board 12, and the header connector 18 is mounted on the circuit board 14. The receptacle connector 16 and the header connector 18 are connected together to electrically connect the circuit boards 12 and 14. In the exemplary embodiment of Figure 1, the receptacle connector 16 and the header connector 18 are oriented such that the connectors 16 and 18 form an approximate right-angle connection between the circuit boards 12 and 14. Alternatively, the receptacle connector 16 and the header connector 18 may be oriented such that the circuit boards 12 and 14 are oriented at any other angle relative to each other, such as, but not limited to, approximately parallel.

[0015] Figures 2 and 3 are perspective views of an exemplary embodiment of the receptacle connector 16. The receptacle connector 16 includes a dielectric housing 20 that, in the illustrated embodiment, holds a plurality of contact modules 22. Referring to Figure 1, each contact module 22 includes a contact lead frame 24 that includes a plurality of signal terminals 26 and a plurality of ground terminals 28. Each signal terminal 26 includes a mounting contact 30 at one end portion of the signal terminal 26 and a mating contact 32 at an opposite end portion of the signal terminal 26. Similarly, each ground terminal 28 includes a mounting contact 34 at one end portion of the ground terminal 28 and a mating contact 36 at an opposite end portion of the ground terminal 28. The mating contacts 32 and 36 extend outward from, and along, a mating face 38 of the contact module 22. The signal terminals 26 are optionally arranged in differential pairs, as the signal terminals 26 are shown in illustrated embodiment. In addition or alternative to the ground terminals 28, one or more of the contact modules 22 may include a ground shield (not shown) that includes the mounting and mating contacts 34 and 36, respectively, and provides a common ground for the corresponding contact module 22.

[0016] Referring again to Figures 2 and 3, a dielectric contact module housing 40 of each contact module 22 holds the corresponding lead frame 24 (Figure 1). Each contact module housing 40 includes a mating end portion 42 that includes the mating face 38 (Figure 1) and a mounting end portion 44 that includes a mounting face 46. In the illustrated embodiment, the mating face 38 is approximately perpendicular to the mounting face 46. However, the mating face 38 and mounting face 46 may be oriented at any other angle relative to each other, such as, but not limited to, approximately parallel. As best seen in Figure 3, the housing 20 includes a mating face 48, an upper shroud 50 extending from the mating face 48, and a plurality of contact channels 52 that extend into the housing 20 through the mating face 48. The mating end portion 42 of each contact module is received in the housing 20 such that each of the mating contacts 32 and 36 (Figure 1) is aligned with a corresponding contact channel 52. The contact channels 52 are configured to receive mating contacts of a header connector (such as, but not limited to, the mating contacts 76 and 80, shown in Figure 5, of the header connector 18, shown in Figures 1, 5, and 6) such that each of the mating contacts 76 and 80 of the header connector 18 engages a corresponding mating contact 32 or 36 of the receptacle connector 16.

[0017] The mounting end portion 44 of each of the contact modules 22 is configured for mounting on a circuit board, such as, but not limited to, the circuit board 12 (Figure 1). The mounting contacts 30 and 34 extend outward from, and along, the mounting face 46 of the contact modules 22 for mechanical and electrical connection to the circuit board 12. Specifically, each of the mounting contacts 30 and 34 is configured to be received within a corresponding via 54 and 56 (Figures 1 and 4), respectively, within the circuit board 12.

[0018] In alternative to the plurality of contact modules 22 held by the housing 20 of the receptacle connector 16, the signal and ground terminals 26 and 28, respectively, of the receptacle connector 16 may be held by a single housing (not shown), which may be integral with, or alternatively held by, the housing 20.

[0019] Referring now to Figure 4, some of the mounting contacts 30 of the signal terminals 26 extend different lengths from the mounting face 46 of the corresponding contact module 22 than others of the mounting contacts 30 (whether the others are on the same contact module 22 or a different contact module 22). For example, a differential pair of first mounting contacts 30a extends a length Li from the mounting face 46, a differential pair of second mounting contacts 30b extends a length L ₂ from the mounting face 46, and a differential pair of third mounting contacts 30c extends a length L ₃ from the mounting face 46. As can be seen in Figure 4, the lengths Lj-L ₃ are each different. Any of the mounting contacts 30 of the receptacle connector 16 may have a different length from the corresponding mounting face 46 than any other mounting contact 30 of the receptacle connector 16. The pattern of the lengths of the mounting contacts 30 shown herein is meant as exemplary only. Although the mounting contacts 30 of each differential pair are shown herein as having approximately the same length from the mounting face 46, alternatively one or more differential pairs includes mounting contacts 30 that have different lengths. [0020] Figure 5 is a perspective view of an exemplary embodiment of the header connector 18. The header connector 18 includes a dielectric housing 60 having a mating end portion 62 that receives the receptacle connector 16 (Figures 1-4) and a mounting end portion 64 for mounting the header connector 18 to a circuit board, such as, but not limited to, the circuit board 14. The mating end portion 62 includes a mating face 66 and the mounting end portion 64 includes a mounting face 68. The housing 60 holds a plurality of signal terminals 70 and a plurality of ground terminals 72. The signal terminals 70 are optionally arranged in differential pairs, as the signal terminals 70 are shown in the illustrated embodiment.

[0021] Each signal terminal 70 includes a mounting contact 74 at one end portion of the signal terminal 70 and the mating contact 76 at an opposite end portion of the signal terminal 70. Similarly, each ground terminal 72 includes a mounting contact 78 at one end portion of the ground terminal 72 and the mating contact 80 at an opposite end portion of the ground terminal 72. The mounting contacts 74 and 78 extend outward from, and along, the mounting face 68 of the header connector 18, while the mating contacts 76 and 80 extend outward from, and along, the mating face 66 of the header connector 18. Each of the mounting contacts 74 and 78 is configured to be received within a corresponding via 82 and 84 (Figures 1 and 6), respectively, within the circuit board 14.

[0022] Referring now to Figure 6, some of the mounting contacts 74 of the signal terminals 70 extend different lengths from the mounting face 68 of the header connector 18 than others of the mounting contacts 74. For example, a differential pair of first mounting contacts 74a extends a length L ₄ from the mounting face 68, a differential pair of second mounting contacts 74b extends a length L ₅ from the mounting face 68, and a differential pair of third mounting contacts 74c extends a length L ₆ from the mounting face 68. The lengths L ₄ -L ₆ are each different. Any of the mounting contacts 74 of the header connector 18 may have a different length from the mounting face 68 than any other mounting contact 74 of the header connector 18. The pattern of the lengths of the mounting contacts 74 shown herein is meant as exemplary only. Although the mounting contacts 74 of each differential pair are shown herein as having approximately the same length from the mounting face 68, alternatively one or more differential pairs includes mounting contacts 74 that have different lengths. [0023] Referring again to Figure 4, the circuit board 12 includes a pair of opposite surfaces 86 and 88. The mounting face 46 of each of the contact modules 22 is configured to be mounted along the surface 86 such that the receptacle connector 16 is mounted on the surface 86 of the circuit board 12. The circuit board 12 includes the plurality of vias 54 and 56 that receive the mounting contacts 30 and 34, respectively, of the respective signal and ground terminals 26 and 28. The vias 56 include an electrical conductor 90 on a surface 92 defining the via 56. Each electrical conductor 90 defines an electrical contact portion for electrical connection with a corresponding one of the mounting contacts 34 of the ground terminals 28. Each electrical conductor 90 may be formed by any suitable method, process, means, and/or the like, such as, but not limited to, plating and/or the like. The electrical conductor 90 of each via 56 is electrically connected to a ground (not shown) of the circuit board 12. Each of the grounds may be formed on the surface 86, the surface 88, or an internal layer (not shown) of the circuit board 12 that extends between the surfaces 86 and 88.

[0024] The vias 54 each include a smaller diameter portion 94 and one or more larger diameter portions 96. For example, a differential pair of first vias 54a includes a smaller diameter portion 94a that extends adjacent to the circuit board surface 86 and a larger diameter portion 96a that extends between the smaller diameter portion 94a and the circuit board surface 88. A differential pair of second vias 54b includes a smaller diameter portion 94b that extends adjacent to the circuit board surface 88 and a larger diameter portion 96b that extends between the smaller diameter portion 94b and the circuit board surface 86. A differential pair of third vias 54c includes a smaller diameter portion 94c that extends adjacent an internal layer (not shown) of the circuit board 12, a larger diameter portion 96c that extends between the smaller diameter portion 94c and the circuit board surface 86, and a larger diameter portion 96cc that extends between the smaller diameter portion 94c and the circuit board surface 88. The smaller diameter portions 94 each include an electrical conductor 98 on a surface 100 defining the smaller diameter portion 94 of the via 54. Each electrical conductor 98 defines an electrical contact portion for electrical connection with a corresponding one of the mounting contacts 30 of the signal terminals 26. The electrical conductor 98 of each via 56 is electrically connected to a signal trace (not shown) of the circuit board 12. For example, the electrical conductors 98 of the smaller diameter portions 94a of the first vias 54a are each electrically connected to a different signal trace on the circuit board surface 86, the electrical conductors 98 of the smaller diameter portions 94b of the second vias 54b are each electrically connected to a different signal trace on the circuit board surface 88, and the electrical conductors of the smaller diameter portions 94c of the third vias 54c are each electrically connected to a different signal trace on an internal layer (not shown) of the circuit board 12.

[0025] As should be apparent from Figure 4 and the above description of the vias 54, the electrical conductors 98 of some of the vias 54 are located at different depths within the corresponding via 54, and relative to the surface 86 of the circuit board 12, than the electrical conductors 98 of others of the vias 54. For example, in the illustrated embodiment, the electrical conductors 98 of the differential pair of first vias 54a are located at a depth Di relative to the circuit board surface 86, the electrical conductors 98 of the differential pair of second vias 54b are located at a depth D ₂ relative to the circuit board surface 86, and the electrical conductors 98 of the differential pair of third vias 54c are located at a depth D ₃ relative to the circuit board surface 86. The depths Dj-D ₃ (measured from a center of a height of the corresponding electrical conductor 98) are each different. The electrical conductor 98 of any of the vias 54 of the circuit board 12 may have a different depth relative to the circuit board surface 86 than the electrical conductor 98 of any other via 54 of the circuit board 12. Moreover, the electrical conductor 98 of each via may have any suitable depth relative to the circuit board surface 86. The pattern of the depths, as well as the specific depths illustrated, of the electrical conductors 98 of the vias 54 shown herein is meant as exemplary only. Although the electrical conductors 98 of each differential pair of vias 54 are shown herein as having approximately the same depth relative to the circuit board surface 86, alternatively one or more differential pairs of vias 54 include electrical conductors 98 having different depths.

[0026] Each electrical conductor 98 may be formed by any suitable method, process, means, and/or the like, such as, but not limited to, plating and/or the like. Each of the vias 54 may be formed using any suitable method, process, means, and/or the like. For example, each of the vias 54 may be formed by forming an opening within the circuit board 12 to define the surface 100 of the smaller diameter portion 94, forming the electrical conductor 98 on the surface 100, and thereafter boring through the circuit board 12 to define the larger diameter portion(s) 96. The boring operation will remove the surface 100 and the electrical conductor 98 from the entirety of the via 54 except for the smaller diameter portion 94.

[0027] Although the vias 54 and 56 are each shown extending completely through the circuit board 12, alternatively one or more of the vias 54 and/or 56 may extend only partially through the circuit board 12.

[0028] Referring again to Figure 6, the circuit board 14 includes a pair of opposite surfaces 102 and 104. The mounting face 68 of the header connector 18 is configured to be mounted along the surface 102 such that the header connector 18 is mounted on the surface 102 of the circuit board 14. The circuit board 14 includes the plurality of vias 82 and 84 that receive the mounting contacts 74 and 78, respectively, of the respective signal and ground terminals 70 and 72. The vias 84 include an electrical conductor 106 on a surface 108 defining the via 84. Each electrical conductor 106 defines an electrical contact portion for electrical connection with a corresponding one of the mounting contacts 78 of the ground terminals 72. Each electrical conductor 106 may be formed by any suitable method, process, means, and/or the like, such as, but not limited to, plating and/or the like. The electrical conductor 106 of each via 84 is electrically connected to a ground (not shown) of the circuit board 14. Each of the grounds may be formed on the surface 102, the surface 104, or an internal layer (not shown) of the circuit board 14 that extends between the surfaces 102 and 104.

[0029] The vias 82 each include a smaller diameter portion 110 and one or more larger diameter portions 112. For example, a differential pair of first vias 82a includes a smaller diameter portion HOa that extends adjacent to the circuit board surface 102 and a larger diameter portion 112a that extends between the smaller diameter portion 110a and the circuit board surface 104. A differential pair of second vias 82b includes a smaller diameter portion HOb that extends adjacent an internal layer (not shown) of the circuit board 14, a larger diameter portion 1 12b that extends between the smaller diameter portion 110b and the circuit board surface 102, and a larger diameter portion 112bb that extends between the smaller diameter portion 11 Ob and the circuit board surface 104. A differential pair of third vias 82c includes a smaller diameter portion 1 10c that extends adjacent to the circuit board surface 104 and a larger diameter portion 1 12c that extends between the smaller diameter portion 110c and the circuit board surface 102. The smaller diameter portions 110 each include an electrical conductor 114 on a surface 1 16 defining the smaller diameter portion 110 of the via 82. Each electrical conductor 1 14 defines an electrical contact portion for electrical connection with a corresponding one of the mounting contacts 74 of the signal terminals 70. The electrical conductor 1 14 of each via 82 is electrically connected to a signal trace (not shown) of the circuit board 14. For example, the electrical conductors 114 of the smaller diameter portions HOa of the first vias 82a are each electrically connected to a different signal trace on the circuit board surface 102, the electrical conductors 114 of the smaller diameter portions HOb of the second vias 82b are each electrically connected to a different signal trace on the circuit board surface 102, and the electrical conductors of the smaller diameter portions 110c of the third vias 82c are each electrically connected to a different signal trace on an internal layer (not shown) of the circuit board 14.

[0030] As should be apparent from Figure 6 and the above description of the vias 82, the electrical conductors 114 of some of vias 82 are located at different depths within the corresponding via 82, and relative to the surface 102 of the circuit board 14, than the electrical conductors 114 of others of the vias 82. For example, in the illustrated embodiment, the electrical conductors 114 of the differential pair of first vias 82a are located at a depth D ₄ relative to the circuit board surface 102, the electrical conductors 114 of the differential pair of second vias 82b are located at a depth D ₅ relative to the circuit board surface 102, and the electrical conductors 114 of the differential pair of third vias 82c are located at a depth D ₆ relative to the circuit board surface 102. The depths D ₄ -D ₆ (measured from a center of a height of the corresponding electrical conductor 114) are each different. The electrical conductor 114 of any of the vias 82 of the circuit board 14 may have a different depth relative to the circuit board surface 102 than the electrical conductor 114 of any other via 82 of the circuit board 14. Moreover, the electrical conductor 114 of each via may have any suitable depth relative to the circuit board surface 102. The pattern of the depths, as well as the specific depths illustrated, of the electrical conductors 114 of the vias 82 shown herein is meant as exemplary only. Although the electrical conductors 114 of each differential pair of vias 82 are shown herein as having approximately the same depth relative to the circuit board surface 102, alternatively one or more differential pairs of vias 82 include electrical conductors 1 14 having different depths. [0031] Each electrical conductor 1 14 may be formed by any suitable method, process, means, and/or the like, such as, but not limited to, plating and/or the like. Each of the vias 82 may be formed using any suitable method, process, means, and/or the like. For example, each of the vias 82 may be formed by forming an opening within the circuit board 14 to define the surface 116 of the smaller diameter portion 110, forming the electrical conductor 114 on the surface 116, and thereafter boring through the circuit board 14 to define the larger diameter portion(s) 112. The boring operation will remove the surface 1 16 and the electrical conductor 114 from the entirety of the via 82 except for the smaller diameter portion 110.

[0032] Although the vias 82 and 84 are each shown extending completely through the circuit board 14, alternatively one or more of the vias 82 and/or 84 may extend only partially through the circuit board 14.

[0033] Referring again to Figure 1, when the receptacle connector 16 is mounted on the circuit board 12, the mounting contacts 30 and 34 are each received within the corresponding via 54 and 56, respectively, such that the mounting contacts 30 and 34 are electrically connected to the respective electrical conductor 98 and 90. Some of the mounting contacts 30 of the signal terminals 26 extend different depths, relative to the circuit board surface 86, into the corresponding via 54 than others of the mounting contacts 30 (whether the others are on the same contact module 22 or a different contact module 22). For example, the first mounting contacts 30a extend the depth Di into the corresponding first vias 54a, the second mounting contacts 30b extend the depth D ₂ into the corresponding second vias 54b, and the third mounting contacts 30c extend the depth D ₃ into the corresponding third vias 54c. Any of the mounting contacts 30 of the receptacle connector 16 may extend a different depth into the corresponding via 54 than any other mounting contact 30 of the receptacle connector 16. The pattern of the depths that the mounting contacts 30 extend into the vias 54 shown herein is meant as exemplary only. Although the mounting contacts 30 of each differential pair are shown herein as extending approximately the same depth into the corresponding via 54, alternatively one or more differential pairs includes mounting contacts 30 that extend different depths into the corresponding via 54.

[0034] When the header connector 18 is mounted on the circuit board 14 as shown in Figure 1 , the mounting contacts 74 and 78 are each received within the corresponding via 82 and 84, respectively, such that the mounting contacts 74 and 78 are electrically connected to the respective electrical conductor 114 and 106. Some of the mounting contacts 74 of the signal terminals 70 extend different depths, relative to the circuit board surface 102, into the corresponding via 82 than others of the mounting contacts 74. For example, the first mounting contacts 74a extend the depth D ₄ into the corresponding first vias 82a, the second mounting contacts 74b extend the depth D ₅ into the corresponding second vias 82b, and the third mounting contacts 74c extend the depth D ₆ into the corresponding third vias 82c. Any of the mounting contacts 74 of the header connector 18 may extend a different depth into the corresponding via 82 than any other mounting contact 74 of the header connector 18. The pattern of the depths that the mounting contacts 74 extend into the vias 82 shown herein is meant as exemplary only. Although the mounting contacts 74 of each differential pair are shown herein as extending approximately the same depth into the corresponding via 82, alternatively one or more differential pairs includes mounting contacts 74 that extend different depths into the corresponding via 82.

[0035] Although the mounting contacts 30 and 74 are shown herein as press-fit contacts, the mounting contacts 30 and 74 may each be any suitable type of electrical contact that enables the mounting contacts 30 and 74 to function as described herein, such as, but not limited to, the press-fit type shown herein, a surface mount type, and/or a solder tail type. The mating contacts 32 and 76 may each be any suitable type of electrical contact that enables the mating contacts 32 and 76 to function as described herein, such as, but not limited to, a press-fit type, a surface mount type, and/or a solder tail type.

[0036] In the exemplary embodiment, the circuit boards 12 and 14 are interconnected using both the receptacle connector 16 and the header connector 18. Alternatively, the receptacle connector 16 directly interconnects the circuit boards 12 and 14 without the header connector 18 intervening between the circuit board 14 and the receptacle connector 16. Similarly, the header connector 18 may directly interconnect the circuit boards 12 and 14 without the receptacle connector 16 intervening between the circuit board 12 and the header connector 18.

[0037] The embodiments described and/or illustrated herein provide an electrical connector that may enable improvement of the density and/or electrical performance of circuit board footprints to achieve higher system densities and/or higher system speeds. For example, the embodiments described and/or illustrated herein, when left at the same density as at least some known systems, may decrease via to via coupling and may increase circuit board footprint impedance. Alternatively, the embodiments described and/or illustrated herein may be able to achieve higher footprint densities than at least some known systems while maintaining the same via to via coupling and impedance levels of such known systems.