Cable connector systems

A cable connector system can include a board connector that attaches to a die package, a cable connector that attaches to the board connector, and a 1 RU panel I/O connector attached to the cable connector.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to connector systems. More specifically, the present invention relates to a connector system that allows cable connectors to be connected to a substrate in a stacked configuration.

2. Description of the Related Art

Cable connector systems that can include differential signal pairs or optical cables that electrically or optically connect an application-specific integrated circuit (ASIC) and a panel are known. A problem with known cable connector systems is providing higher density and higher terabyte throughput between an ASIC and a front panel of a rack-mountable equipment enclosing the ASIC.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of the present invention provide cable connector systems that allow cable connectors to be connected to a board connector in a stacked or nested configuration, while reducing the footprint and stack height required by the board connector. For example, embodiments of the present invention can be used in groups of connectors positioned on one or both opposed surfaces of a die package substrate or on one or both opposed sides of a second substrate that includes a die package and is attached to a host substrate. The embodiments of the present invention can be used to collectively transmit at least 50 terabytes of data with frequency domain crosstalk of −40 dB or better on a standard 70-mm-by-70-mm die package, a 75-mm-by-75-mm die package, an 85-mm-by-85-mm die package, a 120-mm-by-120-mm die package, a 150-mm-by-150-mm die package, or other sized die packages. Embodiments of the present invention can have a height, measured from a mounting surface of the substrate to a top surface of any one of the connectors described herein of about 1.5 mm to about 7 mm.

A board connector can include a housing. The housing can include a first board connector mating interface surface, a first slot defined by the first board connector mating interface surface, a second slot vertically stacked over the first slot, and a first housing wall that partially defines both the first slot and the second slot. A first leadframe assembly can be positioned in the first slot. The first leadframe assembly can include a first signal conductor that can define a first mating end and a second signal conductor that can define a second mating end. A second leadframe assembly can be positioned in the second slot. The second leadframe assembly can include a third signal conductor that defines a third mating end and a fourth signal conductor that defines a fourth mating end. The first mating end and the second mating end can each be positioned closer to the first board connector mating interface surface than the third mating end and the fourth mating end. A first housing wall can extend over the first mating end, the second mating end, the third mating end, and the fourth mating end.

The first slot can be partially defined by the first housing wall, a first wall, and an opposed third wall. The first wall and the opposed third wall can be evenly spaced from a longitudinal centerline that is positioned between the first wall and the opposed third wall. The longitudinal centerline can also be parallel to both the first wall and the opposed third wall.

The second slot can be partially defined by the first housing wall, the first wall, and the opposed third wall, and the first wall and the opposed third wall can each be unevenly spaced from the longitudinal centerline. Alternatively, the second slot can be partially defined by the first housing wall, the first wall, and the opposed third wall, and the first wall and the opposed third wall are evenly spaced from the longitudinal centerline.

The housing can include a third slot vertically stacked over the second slot, a second housing wall that partially defines both the second slot and the third slot, and a third leadframe assembly positioned in the third slot. The third leadframe assembly can include a fifth signal conductor with a fifth mating end and a sixth signal conductor with a sixth mating end. The fifth mating end and the sixth mating end can each be positioned farther from the first board connector mating interface surface than the first mating end, the second mating end, the third mating end, and the fourth mating end.

The third slot can be partially defined by the second housing wall, a first wall, and an opposed third wall, and the first wall and the opposed third wall are unevenly spaced from the longitudinal centerline. Alternatively, the second slot can be partially defined by the second housing wall, a first wall, and an opposed third wall, and the first wall and the opposed third wall can be evenly spaced from the longitudinal centerline.

The board connector housing can further include a fourth slot vertically stacked over the third slot, a third housing wall that partially defines both the third slot and the fourth slot, and a fourth leadframe assembly positioned in the fourth slot. A fourth leadframe assembly can include a seventh signal conductor with a seventh mating end and an eighth signal conductor with an eighth mating end. The seventh mating end and the eighth mating end can each be positioned farther from the first board connector mating interface surface than the first mating end, the second mating end, the third mating end, the fourth mating end, the fifth mating end, and the sixth mating end.

The fourth slot can be partially defined by the third housing wall, a first wall, and an opposed third wall, and the first wall and the opposed third wall can be unevenly spaced from the longitudinal centerline. Alternatively, the fourth slot can be partially defined by the third housing wall, a first wall, and an opposed third wall, and the first wall and the opposed third wall can be evenly spaced from the longitudinal centerline.

The first slot and the second slot can each have a same width. The first slot and the second slot can each have a same depth. The first slot and the second slot can each have different depths. The first slot and the second slot can each receive an identical cable connector. The first, second, third, and fourth signal conductors can each be receptacle conductors. The housing is configured to overhang an edge of a mounting substrate. The housing can have a height of approximately 1.7 mm to approximately 4 mm or approximately 4 mm to approximately 7 mm or approximately 5 mm to approximately 8 mm, or approximately 1.7 mm to approximately 7 mm. The first slot, the second slot, and the third slot can each have a same width. The second slot and the third slot can each have a same width. The first slot, the second slot, and the third slot can each have the same depth. The second slot and the third slot can each have the same depth. The first slot, the second slot, the third slot, and the fourth slot can each have the same width. The third slot and the fourth slot can each have the same width. The first slot, the second slot, the third slot, and the fourth slot can each have the same depth. The third slot and the fourth slot can each have the same depth.

A cable connector can include a cable connector shield. The cable connector shield can include a single sheet of electrically conductive material with a shield arm and a hole. The shield arm can bend back over itself and extend into the hole. The cable connector can mate with a mating connector. The shield arm can be configured to make electrical connection with a mating connector shield. The cable connector can include an insert that includes cable connector signal conductors. Cables can be connected to the cable connector signal conductors. The cable connector can be approximately 1 mm in height.

An electrical connector with differential signal pairs and a unitary connector shield can be provided. The connector shield can include a first connector shield surface, a second connector shield surface opposed to the first connector shield surface, a hole, and a shield arm. The shield arm can bend back over the first connector shield surface and pass through the hole, the first connector shield surface, and the second connector shield surface, such that the shield arm is configured to contact a mating connector shield of a mating connector when the electrical connector is mated with the mating connector. The electrical connector can be a cable connector.

A panel can be provided. The panel can define a 1 RU area and at least two-hundred and fifty-seven 56-GHz differential signal pairs positioned in the 1 RU area, or at least two-hundred and eighty-nine 56-GHz differential signal pairs can be positioned in the 1 RU area, or at least three hundred 56-GHz differential signal pairs can be positioned in the 1 RU area, or at least four hundred 56-GHz differential signal pairs can be positioned in the 1 RU area, or at least five hundred 56-GHz differential signal pairs can be positioned in the 1 RU area.

A tray can be provided. The tray can include a first airflow zone and a second airflow zone. The first airflow zone and the second airflow zone can each be positioned parallel to each other, can each be positioned immediately adjacent to each other, and can each be serviced by separate fans. Back-to-back, on-board transceivers can be positioned in the first airflow zone. A die can be positioned in the second airflow zone.

Mated electrical right-angle connectors can have a mated stack height greater than zero but less than approximately 5 mm.

A substrate can be provided. The substrate can include a first linear array of pads that can extend along a first pad centerline and can include first and second end pads at opposite ends of the first linear array of pads. A second linear array of pads can extend along a second pad centerline and can include third and fourth end pads at opposite ends of the second linear array of pads. A possible first weld tab land on the substrate can have a first weld tab centerline. A possible second weld tab land on the substrate can have a second weld tab centerline. A first pad centerline can be positioned parallel to the second pad centerline. The first linear array of pads can be offset from the second linear array of pads by more than a row pitch. The first end pad and the third end pad can each be on a same side of the substrate. The second end pad and the fourth end pad can each be on a same side of the substrate opposite to the first end pad and the third end pad. The first weld tab centerline and the second weld tab centerline can each be positioned parallel to each other and perpendicular to the first pad centerline and to the second pad centerline. A first pad distance from a center of the second end pad to the second weld tab centerline can be less than a second pad distance from a center of the third end pad to the first weld tab centerline. A third pad distance between the first end pad in the first linear array of pads to the first weld tab centerline can be greater than the first pad distance. The first pad centerline and the second pad centerline do not intersect the first weld tab land or the second weld tab land.

The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the attached drawings.

DETAILED DESCRIPTION OF EMBODIMENTS

The cable connector systems described herein are able to transport, i.e., transmit and/or receive, signals up to 56 GHz NRZ and/or 112 PAM4. The cable connector systems may be applied to die package substrates or extension cards attached to die substrates that are 70 mm by 70 mm, 75 mm by 75 mm, 80 mm by 80 mm, 85 mm by 85 mm, 90 mm by 90 mm, 95 mm by 95 mm, 100 mm by 100 mm, 105 mm by 105 mm, 110 mm by 110 mm, or any die package having N by N dimensions, where N is greater than or equal to 70 mm and N is less than or equal to 200 mm. The cable connector systems can also be applied to a substrate that includes a die package, a die substrate, or an extension card attached to a die package or die substrate.

FIG.1shows a cable connector system10. A cable connector system10can include a board connector12and at least one, at least two, at least three, at least four, or four or more cable connectors14. The board connector12can be configured to electrically, physically, or electrically and physically connect to a suitable substrate (not shown inFIG.1), including, for example, a die package, a die substrate, an extension card attached to a die package or a die substrate, a host substrate, etc. The board connector12can include a housing16, which can include a first housing18and a second housing20. The cable connector or connectors14can include one or more cables22and can each be releasably connected to the board connector12, perhaps in order starting with the cable connector14closest to a surface of a mounting substrate. Alternatively, the order can be reversed, starting with the cable connector14farthest in distance (height H) from a surface of the mounting substrate, or the cable connectors14can be simultaneously mated to the board connector12. The cable connectors14can be connected to a board connector12or the first housing18of the board connector12by inserting the cable connectors14from a direction parallel or substantially parallel, within manufacturing tolerances, to the surface of the substrate on which the board connector12is mounted. Each cable connector14can be attached to one end of a cable22, and an opposed end of the cable22can be attached to a panel connector, a board connector, I/O connector (as shown, for example, inFIG.30), etc. The board connector12and/or the cable connector(s)14can include a magnetic absorbing material that is either electrically conductive or electrically non-conductive. The magnetic absorbing material can be located, for example, on the housings and/or on the conductors of the board connector12and/or the cable connector14. With the vertically stacked arrangement of cable connectors14, it is possible to achieve a stack height of the cable connector system10, that is determined by the height H of the housing16of the board connector12, which can be about 1.0 mm to about 7.0 mm tall, or about 1.7 mm to about 6.8 mm, or about 1.7 mm to about 4 mm, or about 4 mm to about 7 mm, or about 5 mm to about 8 mm, depending on the total number of rows of cable connectors14. The portion of the cables22adjacent to or connected to the cable connectors14can extend parallel or substantially parallel, within manufacturing tolerances, to a substrate to which the board connector12is mounted. Each cable connector14, alone, can have a height of approximately 1 mm, within manufacturing tolerances.

FIG.2shows a cable system10that can include a board connector12that has a height H and cable connectors14that are vertically stacked such that each cable connector14a,14b,14c,14ddoes not fully overlap an immediately adjacent cable connector14. Each cable connector14can include corresponding copper cables22, such as shielded differential twin axial cables. The board connector12can include a housing16, that can include a first housing18and a second housing20. Where there are at least three vertically stacked cable connectors14,14a,14b, an overlap OV between a first cable connector14and an immediately adjacent second cable connector14acan be larger than an overlap OV1between the second cable connector14aand the third cable connector14b.

FIG.3is a bottom perspective view of the cable connector system10shown inFIGS.1and2. A board connector12that can have a two-part housing16, divided into separate or integrally formed first and second housings18,20. The cable connector system10can include connectors14and respective cables22and leadframe assemblies24a,24b, wherein the leadframe assemblies24a,24bcan each include electrical conductors, such as signal conductors26or optional ground conductors28. The electrical conductors can be evenly spaced apart, centerline to centerline. A distance between respective centerlines of two adjacent electrical conductors can define a conductor pitch. A board connector shield40can terminate in ground/power/reference conductors28and can be positioned adjacent to a corresponding one of the leadframe assemblies24a,24b. Alternatively, a leadframe assembly24a,24bcan be molded or insert molded with a board connector shield40. Each signal conductor26can terminate in a solder ball30, a solder slug, any suitable SMT, any through hole or plated through hole technology, etc.

If there are N number of cable connectors14, then the corresponding board connectors12can include N number of leadframe assemblies24a,24bor wafers, one for each corresponding cable connector14. If there are a total of P number of cables22in a corresponding cable connector14, then the corresponding board connector12can include 2×P electrical conductors26,28, assuming each cable22is a twin axial cable with two center cable conductors38. If the cables22only have a single center cable conductor38, then the board connector12can include P electrical conductors, such as signal conductors26and optional ground conductors28.

Two sets of immediately adjacent leadframe assemblies24a,24bare shown. Two immediately adjacent leadframe assemblies24a,24bcan be offset with respect to each other in a horizontal direction D that is perpendicular to an insertion direction I of the cable connectors14. As shown inFIG.3, every leadframe assembly24ais horizontally offset with respect to every other leadframe assembly24bin the housing16. Each cable22can be a shielded cable that can include an insulative jacket32, an electrically conductive cable shield34, a cable dielectric36, and a single cable conductor or a pair of cable conductors38. A board connector shield40can electrically, physically, or electrically and physically connect to a corresponding cable connector shield42. Each cable shield34can electrically, physically, or electrically and physically connect with a corresponding cable connector shield42.

FIG.4is similar toFIG.1, but with the cable connectors14removed. The board connector12can include a housing16. The housing16can include a first housing18, a second housing20, and one or more leadframe assemblies24a,24b. Although the housing16can receive four leadframe assemblies24a,24b, any number of leadframe assemblies24a,24bcan be used. The first housing18or second housing20can define or include one or both of a standoff and a retention tab46.

As shown inFIG.5, the first housing18and the second housing20can be connected together by inserting the retention tabs46into corresponding housing holes48in the first housing18. Alternatively, the retention tabs46and the corresponding housing holes48can be reversed. In general, the first and second housings18,20can be connected in any suitable manner. The retention tabs46can also be used to secure the board connector12to a substrate. For example, the retention tabs46can be soldered to a substrate.

The housing16or first housing18can define four slots50,50a,50b,50c. At least one or both of the first slot50and second slot50acan each open at first board connector mating interface surfaces52aof the housing16or first housing18. At least one or both of the third slot50band fourth slot50ccan each open at second board connector mating interface surfaces52bof the housing16or the first housing18. The first board connector mating interface surface52acan each lie in a first plane FP that is generally perpendicular to a mounting interface plane MIP that is parallel to a board connector mounting interface surface44of the housing16. The second board connector mating interface surfaces52bcan each lie in a second plane SP that is generally perpendicular to the mounting interface plane MIP. The first plane FP and the second plane SP can be parallel to each other, and both generally perpendicular to the mounting interface plane MIP. The first board connector mating interface surfaces52aand the second board connector mating interface surfaces52bcan be spaced apart from one another. The second board connector mating interface surfaces52bcan be positioned vertically above the first board connector mating interface surfaces52a, and can be recessed away from the first board connector mating interface surfaces52ain a direction toward the second housing20.

Each of the four slots50,50a,50b,50ccan receive a corresponding one of four cable connectors14. A different number of slots50-50ccan be included if a corresponding different number of cable connectors14is used. The slots50-50ccan each be positioned parallel to one another. A first slot50may be positioned immediately adjacent to a mounting substrate, such as a printed circuit board (PCB) (shown, for example, inFIG.12), and stacked vertically over each other in a direction along the height H of the housing16. The first slot50can be defined by a first wall54, a first housing wall56, and a third wall58. Three walls54,56,58are shown, but another wall that spans the first and third walls54,58can also be used. When only three walls54,56,58are used, the first slot50leaves a portion of a mounting substrate exposed. A second slot50amay be defined by four walls, such as a first wall54a, a second housing wall56a, a third wall58a, and the first housing wall56of the first slot50. Mating ends62of signal conductors26and board connector shields40can protrude into the respective slots50,50a. In this embodiment, the first slot50and the second slot50acan be horizontally offset, such that a pair of signal conductors26positioned in the first slot50can be offset from a corresponding pair of signal conductors26apositioned in the second slot50ain a horizontal direction by a partial row pitch, a full row pitch, more than a row pitch, a full conductor pitch, at least two conductor pitches, at least three conductor pitches, more than two conductor pitches, or more than three conductor pitches. A conductor pitch can be the distance between centerlines of two adjacent signal conductors. For a row pitch, a corresponding pair of signal conductors can have the same position numbers, such as the last two signal conductors26bpositioned in the third slot50b, in a left-to-right direction, and the last two signal conductors26cpositioned in the fourth slot50c, in a left-to-right direction. The first housing18can define indents60. The indents60can be defined such that there is an indent60aligned at an end of each row or slot50-50c. The indents60can alternate, slot to slot or row to row, such that there are an equal number of indents60on each side of the housing16or first housing18.

A third slot50bmay be vertically stacked over the first slot50and the second slot50aand can be positioned immediately adjacent to the second slot50ain a vertical direction along a height H of the housing16. The third slot50bcan be defined by a first wall54b, a third housing wall56b, a third wall58b, and the second housing wall56aof the second slot50a. A fourth slot50cmay be vertically stacked over the first slot50, the second slot50a, and the third slot50band can be positioned immediately adjacent to the third slot50bin a vertical direction along a height H of the housing16. The fourth slot may be defined by four walls, such as a first wall54c, a fourth housing wall56c, a third wall58c, and the third housing wall56bof the third slot50b.

Mating ends62of signal conductor pairs26b,26cand board connector shields40b,40ccan protrude into the respective slots50b,50c. Similar to the first and second slots50,50a, the third slot50band the fourth slot50ccan be horizontally offset in a direction perpendicular to an insertion direction I of cable connectors14, such that a signal conductor26bpair positioned in third slot50bcan be offset from corresponding signal conductor pair26cpositioned in the fourth slot50cby a partial row pitch, a full row pitch, or more than a row pitch.

FIG.6shows a first housing18. A first slot50can be defined by at least three walls or only three walls, such as the first wall54, the opposed third wall58, and the first housing wall56that can span the first wall54and the opposed third wall58. The first housing wall56can partially define the first slot50and the second slot50a. The first housing wall56can define a first wall edge64.

A second slot50acan be defined by at least four walls or only four walls, such as the first wall54a, the opposed third wall58a, the first housing wall56that can span the first wall54aand the opposed third wall58a, and the second housing wall56athat can span the first wall54aand the opposed third wall58a. Second housing wall56acan partially define both the second slot50aand the third slot50band can define a second wall edge64a.

A third slot50bcan be defined by at least four walls or only four walls, such as the first wall54b, the opposed third wall58b, the second housing wall56athat can span the first wall54band the opposed third wall58b, and the third housing wall56bthat can span the first wall54band the opposed third wall58b. Third housing wall56bcan partially define both the third slot50band the fourth slot50cand can define a third wall edge64b.

A fourth slot50ccan be defined by at least four walls or only four walls, such as a first wall54c, an opposed third wall58c, a third housing wall56bthat can span the first wall54cand the opposed third wall58c, and a fourth housing wall56cthat can span the first wall54cand the opposed third wall58c. Third housing wall56bcan partially define both the third slot50cand the fourth slot50d. The fourth housing wall56cand can define a fourth wall edge64c. All of the slots50-50ccan have the same width, the same depth, different widths, or different depths.

The first wall edge64, the second wall edge64a, the third wall edge64b, and the fourth wall edge64ccan each be vertically stair-stepped along a height H1of the first housing18. For example, the first wall edge64of the first housing wall56can be positioned farther away from a rear, vertical wall66of the first housing18than the second wall edge64a, the third wall edge64b, or the fourth wall edge64c. As measured from the rear, the vertical wall66of the first housing18, the second wall edge64acan be positioned farther away from the rear, vertical wall66than the third wall edge64band the fourth wall edge64c. Alternatively, the first wall edge64and the second wall edge64acan each be spaced the same distance from the rear, vertical wall66of the first housing18. As measured from the rear, vertical wall66of the first housing18, the third wall edge64bcan be positioned farther away from the rear, vertical wall66of the first housing18than the fourth wall edge64cof the fourth housing wall56c. Alternatively, the third wall edge64band the fourth wall edge64ccan each be spaced the same distance from the rear, vertical wall66of the first housing18. Grooves68can receive portions of a corresponding molded leadframe assembly24a,24b.

As shown inFIG.7, each slot50,50a,50b,50ccan have a corresponding pair of grooves68into which a corresponding molded leadframe assembly24a,24bor wafer can be inserted. Grooves68in immediately adjacent slots can be offset from one another in a horizontal direction, which results in corresponding leadframe assemblies24a,24bbeing offset from one another. To ensure consistent electrical performance, indents60can be provided in the first housing18to ensure that each slot50a-50chas approximately the same amount of dielectric material on each side. The first housing18can have weld tab holes70into which weld tabs can be inserted. These weld tabs are not used to connect the first housing18to the second housing20, but can be used to secure the first housing18, and thus the board connector12, to a mounting substrate.

As shown inFIG.8, the second housing20can include grooves68into which wafers or leadframe assemblies24a,24bcan be inserted. Opposed pairs of grooves68can be offset to ensure that the leadframe assemblies24a,24bare offset with respect to each other. The second housing20can include a notch72which can receive a leadframe assembly included in the first housing18. The second housing20can be used to more accurately position leadframe assemblies24a,24bincluded in the second housing20and the first housing18which, in turn, more accurately position conductor mounting ends, solder balls, etc. of the signal conductors26and ground plane40tails with corresponding SMT pads, plated through holes, or other suitable termination defined on a surface of a mating substrate. The second housing20also provides mechanical stability to the overall housing16.

FIG.9is another view of the cable connector system10without the housing16, including the first housing18and the second housing20and plastic or overmolding selectively removed from the leadframe assemblies24a,24bof the board connector12for clarity.FIG.9shows the signal conductors26deflected in a mated condition.

A first leadframe assembly74can include a second signal section84and a second board connector shield section88. Second, third, and fourth leadframe assemblies76,78,80can each include a first signal section82, a second signal section84, a first board connector shield section86, and a second board connector shield section88. First signal sections82can be separately attached to the first board connector shield sections86, and the second signal sections84can be separately attached to the second board connector shield sections88. Alternatively, the second signal sections84and respective second board connector shield sections88can be molded together, and the first signal sections82and respective first board connector shield sections86can be molded together. The board connector12can be devoid of discrete ground conductors positioned between adjacent signal conductors26or between adjacent signal conductor pairs26a,26b.

A first signal section82and a corresponding second signal section84can define a right angle. A first signal section82of the third leadframe assembly78can be longer in length and taller in height than a first signal section82of the second leadframe assembly76. A first signal section82of the fourth leadframe assembly80can be longer in length and taller in height than a first signal section82of the third leadframe assembly78.

In the second, third, and fourth leadframe assemblies76,78,80, respective first and second signal sections82,84can be connected together in any suitable manner, including, for example, by soldering, welding, sonic welding, laser welding, etc. A first board connector shield section86and a respective second board connector shield section88of each board connector shield40can be connected together in any suitable manner, such as the methods discussed in this paragraph with respect to first and second signal sections82,84. In one embodiment, signal conductors26of the second signal section84are inserted into a corresponding one of holes defined by signal conductors26of the second signal section84and the first and second signal sections82,84are soldered or welded. A first board connector shield section86and a second board connector shield section88can be similarly attached. Board connector shield tail92can extend from the board connector shield40and be in-line with tails of signal conductors26carried by a corresponding first signal section82.

FIG.10is similar toFIG.9, except the first leadframe assembly74and the second leadframe assembly76are not horizontally offset with respect to each other in a vertically stacked or height direction, and the third leadframe assembly78and the fourth leadframe assembly80are not horizontally offset with respect to each other in a vertically stacked or height direction. However, the first leadframe assembly74and second leadframe assembly76are both offset with respect to the third leadframe assembly78and the fourth leadframe assembly80in a vertically stacked or height direction. All of the leadframe assemblies74,76,78,80are independent of each other, so the first, second, third and fourth leadframe assemblies74,76,78,80shown inFIGS.9and10can be used with any of the cable connector systems10,10A,10B,10C shown herein. As discussed above, leadframe assemblies24a,24b, such as first, second, third and fourth leadframe assemblies74,76,78,80can be inserted into the housing16, perhaps via grooves68, and retained in the housing16by an interference fit. Each of the board connector shields40can include one or more arms90that can engage with a cable connector shield42of a corresponding cable connector14. The signal conductors26can be grouped together in signal conductor pairs26a,26bto transmit differential signals.

A first leadframe assembly74is shown inFIG.11, but this paragraph applies to all leadframe assemblies24a,24b. Each signal conductor pair26a,26bof signal conductors26can include a cantilevered web94that extends between facing edges of the pair26a,26bof signal conductors26and a button96located on a side of the signal conductor pair26a,26b. The web94and/or button96are optional. Each board connector shield40can define a cutout or air void98directly beneath a signal conductor pair26a,26b. Each leadframe assembly24a,24bcan include an insert100that surrounds portions of the signal conductors26. The insert100can be manufactured by insert molding a dielectric material around the signal conductors26. The insert100can also surround a portion of a second board connector shield section88. Alternatively, each molded leadframe assembly24a,24bcan have its own insert100, and each second board connector shield section88can have its own insert100. The leadframe assemblies24a,24bcan be devoid of signal conductors26positioned between adjacent signal conductor pairs26a,26b.

FIG.12is similar toFIG.5, except the board connector12A has a different slot arrangement and is shown with an optional mounting substrate102, such as a PCB. UnlikeFIG.5, wherein the slots50,50a,50b,50are alternatively offset or horizontally staggered in a vertically stacked or height direction H2, the first and second slots50,50ainFIG.12are not horizontally offset or staggered with respect to one another in a vertically stacked, vertically stepped, or height direction H2. The third and fourth slots50b,50binFIG.12are also not horizontally offset or staggered in a vertical stacked direction or height direction H2. However, the third and fourth slots50b,50c, which can generically be described as immediately adjacent first and second slots, can both be horizontally offset or staggered with respect to both the first and second slots50,50ain a vertically stacked direction, stepped direction, stacked direction, or height direction H2.

FIG.13shows a board connector12A with a first housing18. A first slot, such as second slot50a, can be partially defined by a first housing wall, such as second housing wall56a, a surface defined by a first wall54a, and a surface defined by an opposed third wall58a. The surface of the first wall54aand the surface of the opposed third wall58acan be evenly spaced from a longitudinal centerline CL positioned between the first wall54aand the third wall58a, parallel to both the first wall54aand the opposed third wall58a. A second slot, such as third slot50b, can be partially defined by a first housing wall, such as a second housing wall56a, a surface defined by a second first wall54b, and a surface defined by an opposed second third wall58b. The surface of the second first wall54band the surface of the opposed second third wall58bcan both be unevenly spaced away from the longitudinal centerline CL. Stated differently,FIGS.1and13show that first and second slots, such as first slot50and second slot50aor second slot50aand third slot50b, can be positioned immediately adjacent to each other and can be horizontally offset from each other in a vertically stacked or height direction. Cable connectors14inserted in the first and second slots are likewise horizontally offset from each other in a vertically stacked or height direction. As shown inFIGS.12and13, at least four slots50-50ccan also be arranged into two pairs of slots. The first pair of slots can be spaced apart, but not horizontally offset with respect to each other in a vertically stacked or height direction. However, a second pair of slots can be horizontally offset from the first pair of slots in a vertical stacked or height direction. The corresponding cable connectors14received in the first pair of slots can be horizontally offset in a vertically stacked or height direction with respect to cable connectors14received in the second pair of slots. Each ofFIGS.1,12,13, and15show that in any given pattern of slots, a first slot and an immediately adjacent second slot, such as second and third slots50a,50binFIGS.12and13, can be offset with respect to each other. As shown inFIGS.12and13, it is also possible to have a first slot and an immediately adjacent second slot that are not horizontally offset with respect to each other.

In this embodiment, one of the electrical conductors, such as signal conductors26a, positioned in the second slot50a(or first slot50) can be horizontally offset from a corresponding electrical conductor, such as signal conductor26bpositioned in the third slot50b(or second slot50a) in a horizontal direction by no row pitch RP1(i.e., no offset), a partial row pitch RP1that is less than a full row pitch RP1, a full row pitch RP1, more than a row pitch RP1, a full conductor pitch CP, at least two conductor pitches CP, at least three conductor pitches CP, more than two conductor pitches CP, or more than three conductor pitches CP, where a conductor pitch CP is a distance between centerlines of two adjacent electrical conductors or two adjacent signal conductors26aor26b. Corresponding electrical conductors or signal conductors26a,26bcan have the same position numbers, left to right, such as the last signal conductor26apositioned in the second slot50a(or first slot50) and, left to right, the last signal conductor26bpositioned in the third slot50b(or second slot50a).

One pair of signal conductors26apositioned in second slot50a(or first slot50) can be offset from a corresponding pair of signal conductors26bpositioned in the third slot50b(or second slot50) in a horizontal direction by no conductor row pitch RP2(i.e., no offset), a partial conductor row pitch RP2that is less than a full conductor row pitch RP2, a full conductor row pitch RP2, more than a conductor row pitch RP2, a full conductor pitch CP, at least two conductor pitches CP, at least three conductor pitches CP, more than two conductor pitches CP, or more than three conductor pitches CP, where a conductor pitch CP is a distance between centerlines of two adjacent electrical conductors, such as two signal conductors26aor26b. Corresponding pairs of signal conductors26a,26bcan have the same position numbers, left to right, such as the last two signal conductors26apositioned in the second slot50a(or first slot50) and, left to right, the corresponding last two signal conductors26bpositioned in the third slot50b(or second slot50a).

FIG.14shows a cable connector system10A that is similar toFIG.12, but the first housing18A of the board connector12A can define an overhang104that extends below the second housing20A and a major surface106of a substrate102. Cable connectors14are arranged in a first pair of cable connectors108and a second pair of cable connectors110. The first pair of cable connectors108can both be horizontally offset from the second pair of cable connectors110in a vertically stacked or height direction by an equal distance. The first pair of cable connectors108both have first sidewalls112that both lie in a first common plane. The second pair of cable connector110both have second sidewalls114that both lie in second common plane that is spaced away from and is parallel to the first common plane. The overhang104can include an overhang wall104ato provide support for a cable conductor14.

FIG.15shows a 1-by-2 cable connector system10B that is similar to the 1-by-4 cable connector system10shown inFIGS.1-10. The cable connector system10B can include a board connector12B, a cable connector14, a housing16B that can include a first housing18B and a second housing20B, cables22, and an optional mounting substrate102. The first housing18B can define a first slot50and a second slot50a. The second slot50acan be horizontally offset with respect to the first slot50in a vertically stacked or height direction, such that a first sidewall112A of one of the two cable connectors14and second sidewall114aof the other one of the two cable connectors14do not lie in a common plane. Respective first end walls116of the two cable connectors14are not coincident with one another and do not overlap one another.

FIG.16shows a cable connector system10C that is similar to the cable connector system10B ofFIG.15, except the housing16C, such as the first housing18C, can define an overhang104C. The overhang104C can extend below the second housing20C and a major surface106of a substrate102. The overhang104C can define an overhang wall104ato help support a mating cable connector14.

FIG.17shows a cable connector14that can be used with any of the board connectors12,12A,12B,12C described herein. The cable connector14can include cables22, cable connector signal conductors120, a cable connector shield42, and a cover122. AlthoughFIG.17shows eight twin axial cables and eight signal conductor pairs26a,26b, any number or types of cables22and signal conductor pairs26a,26bcan be used, including, for example, a coaxial cable with a single center conductor.

As shown inFIG.18, the cable conductors38of the cables22can be attached to respective cable connector signal conductors120. The cable shield34can be electrically attached to the cable connector shield42. A cable connector insert118can surround portions of the cable connector signal conductors120and can be attached to the cable connector shield42. For example, the cable connector insert118can be manufactured by insert molding. Cable connector shield42can define a cantilevered shield arm124that is bent back over itself.

FIG.19shows a board connector shield40and a cable connector shield42that electrically connect, physically connect, or both electrically connect and physically connect. The shield arm124of the cable connector shield42can be bent back onto itself. A shield arm mating end138of the shield arm124can extend through a corresponding hole126defined by the cable connector shield42, passing through and below a first cable connector shield surface128and an opposed second cable connector shield surface130of the cable connector shield42, which allows the shield arm124to electrically and/or physically contact a board connector shield40of the board connector12when the cable connector14is inserted into any one of board connectors12,12A,12B,12C. Spacing between the first leadframe assembly74and the second leadframe assembly76can be approximately 1.35 mm. Spacing between the second leadframe assembly76and the third leadframe assembly78can be approximately 3 mm. Spacing between the third leadframe assembly78and the fourth leadframe assembly80can be approximately 1.35 mm.

The shield arm124of the cable connector shield42, as well as cable connector insert118that includes cable connector signal conductors120, is further shown inFIG.20. The cable connector shield42can include a single sheet of electrically conductive material, such as copper, beryllium copper or other suitable material, that is formed into a unitary cable connector shield42. The cable connector shield42can include a shield arm124. The shield arm124can have a first shield arm portion132. A bent or U-shaped second shield arm portion134can be attached to the first shield arm portion132and can curve in a second direction toward the cable connector shield42. A third shield arm portion136can be connected to the second shield arm portion134and can extend in a third direction toward the cable connector shield42and opposite to the first shield arm132direction, such that a shield arm mating end138of the third shield arm portion136is received in a hole126defined by the cable connector shield42. The first shield arm portion132of the shield arm124and the shield arm mating end138of the third shield arm portion136may both electrically connect and/or physically contact a board connector shield40of a mating connector. Bending the shield arm124back onto itself shortens the ground or return path when the shield arm124contacts or connects with a corresponding board connector shield40of the board connecter12,12A,12B,12C, increasing electrical performance of the cable connector14or the mated combination of the cable connector14and the board connector12. The third shield arm portion136and the associated shield arm mating end138flexes in a direction away from the first cable connector shield surface128of the board connector shield40, creating a normal force.

FIGS.21-25show a method of manufacturing a cable connector shield42, cable connector signal conductors120and shield arms124from a single stamping of material.FIG.21shows a flat stamping cable connector shield42that can include respective cable connector signal conductors120and respective shield arms124. The cable connector shield42, cable connector signal conductors120and shield arms124are all formed from stamping a single metal sheet. Any suitable metal sheet can be used. InFIG.22, a progressive die is used to bend and shape portions of the flat stamping to further create the cable connector shield42, cable connector signal conductors120and shield arms124. Cable connector signal conductors120can be temporarily held in place with removable tie bars T. InFIG.23, insert molding can form the cable connector insert118, which allows the tie bars T to be removed. Once the tie bars T are removed, the cable connector insert118can electrically isolate the cable connector signal conductors120from the cable connector shield42and the shield arms124. The outer frame can also be removed when the tie bars T are removed. As shown inFIG.24, removing the tie bars T disconnects the cable connector signal conductors120from the shield arms124and the rest of the cable connector shield42so that the cable connector signal conductors120are electrically isolated from the cable connector shield42. InFIG.25, the shield arms124can be bent through corresponding holes126defined by the first cable connector shield surface128and the opposed second cable connector shield surface130.

FIGS.26and27show substrates with substrate footprints that correspond to respective connector footprints of respective board connectors12,12A,12B,12C. For 1-by-2 board connectors12B,12B,FIG.26shows a generic mounting substrate160, such as a die substrate, expansion card substrate, or host substrate that defines a first substrate footprint140. The first substrate footprint140can include a first linear array of pads144. The first linear array of pads144can extend along a first pad centerline PC1. A second linear array of pads146can extend along a second pad centerline PC2. The first pad centerline PC1can be positioned parallel to the second pad centerline PC2.

In this embodiment, one of the pads of the first linear array of pads144, such as a pad157that receives a corresponding one of signal conductors26, can be horizontally offset from a corresponding one of the pads of the second linear array of pads146, such as pad157athat receives a corresponding one of signal conductors26a. The horizontal offset can be by no pad row pitch RP (i.e., no offset), a partial pad row pitch RP1that is less than a full pad row pitch RP, a full pad row pitch RP, more than a pad row pitch RP, a full pad pitch PP, at least two pad pitches PP, at least three pad pitches PP, more than two pad pitches PP, or more than three pad pitches PP. A pad row pitch RP can be measured from a centerline of a pad in the first linear array of pads144and a corresponding pad in the second linear array of pads146. A pad pitch PP can be a distance between centerlines of two adjacent pads in the respective first or second linear arrays144,146. For pad row pitch RP, corresponding pads can have the same position number, left to right, in each of the first and second linear arrays of pads144,146. For example, corresponding pads can each be the last or second to last pads157,157a, left to right, in each of the first and second linear arrays of pads144,146.

A first weld tab land152and a second weld tab land154can be positioned on the generic mounting substrate160, adjacent to the second linear array of pads146. The first weld tab land152can have a first weld tab centerline TCL1, and the second weld tab land154can have a second weld tab centerline TCL2. The first weld tab centerline TCL1and the second weld tab centerline TCL2can each be positioned parallel to each other and perpendicular to the first pad centerline PC1and the second pad centerline PC2. A first pad distance PD1, measured from a center of end pad156in the first linear array of pads144to the second weld tab centerline TCL2, is less than a second pad distance PD2measured from a center of the opposite end pad158in the second linear array of pads146to the first weld tab centerline TCL1. A third pad distance PD3, measured between the other end pad162in the first linear array of pads144and the first weld tab centerline TCL1, can be greater than the first pad distance PD1or the second pad distance PD2. The first pad centerline PC1and the second pad centerline PC2do not intersect the first weld tab land152or the second weld tab land154.

For a 1-by-4 board connector12,12A, as shown inFIG.27, a second substrate footprint142is similar to the first substrate footprint140discussed above. The second substrate footprint142can be defined on a generic mating substrate160and can include a first linear array of pads144. The first linear array of pads144can extend along a first pad centerline PC1. A second linear array of pads146can extend along a second pad centerline PC2. The first pad centerline PC1can be positioned parallel to the second pad centerline PC2.

One of the pads of the first linear array of pads144, such as a pad157that receives a corresponding one of signal conductors26b, can be horizontally offset from a corresponding one of the pads of the second linear array of pads146, such as pad157athat receives a corresponding one of signal conductors26a, by no pad row pitch RP (i.e., no offset), a partial pad row pitch RP that is less than a full row pitch RP, a full pad row pitch RP, more than a pad row pitch RP, a full pad pitch PP, at least two pad pitches PP, at least three pad pitches PP, more than two pad pitches PP, or more than three pad pitches PP. A pad row pitch RP can be the distance from a centerline of a pad in the first linear array of pads144and a corresponding pad in the second linear array of pads146. A pad pitch PP can be the distance between centerlines of two adjacent pads in the respective first or second linear arrays144,146. For pad row pitch RP, corresponding pads can have the same position number, left to right, in each of the first and second linear arrays of pads144,146. For example, corresponding pads can each be the last or second to last pads157,157a, left to right, in each of the first and second linear arrays of pads144,146.

A first weld tab land152and a second weld tab land154can be positioned on the generic mounting substrate160. The first weld tab land152can have a first weld tab centerline TCL1, and the second weld tab land154can have a second weld tab centerline TCL2. The first weld tab centerline TCL1and the second weld tab centerline TCL2can each be positioned parallel to each other and perpendicular to the first pad centerline PC1and the second pad centerline PC2. A first pad distance PD1, measured from a center of end pad156in the first linear array of pads144to the second weld tab centerline TCL2, is less than a second pad distance PD2measured from a center of the opposite end pad158in the second linear array of pads146to the first weld tab centerline TCL1. A third pad distance PD3, measured between the other end pad162in the first linear array of pads144to the first weld tab centerline TCL1, can be greater than the first pad distance PD1or the second pad distance PD2. A third linear array of pads164can extend along a third pad centerline PC3that extends parallel to the first pad centerline PC1. A fourth linear array of pads166can extend along a fourth pad centerline PC4that extends parallel to the first pad centerline PC1. The first linear array of pads144can be positioned with no row pitch offset between the first linear array of pads144and the third linear array of pads164. The second linear array of pads146can be positioned with no row pitch offset between the second linear array of pads146and the fourth linear array of pads166. The first pad centerline PC1, the second pad centerline PC2, the third pad centerline PC3and the fourth pad centerline PC4do not intersect the first weld tab land152or the second weld tab land154.

FIG.28shows a die substrate168, a die170mounted to the die substrate168, and a first group of a plurality of cable connector systems10,10A,10B,10C. Each cable connector system can include a board connector12and a corresponding cable connector14. The die170can be a chip and can be included on a first die substrate surface172of the die substrate168. The combination of the die substrate168and the die170can be referred to as a die package174. The first die substrate surface172may include optional serializer/deserializer chips (not shown). The board connectors12and the cable connectors14can be in electrical contact with the die170. Placing the connector systems10directly on the die package174helps to eliminate trace losses from the die package174to a generic mounting substrate160A.

The die substrate168can be any suitable size, such as an approximate 85-mm-by-85-mm printed circuit board, measured along two intersecting first and second die edges176,178of the die substrate168. The die substrate168can be other sizes. The die package174is preferably square, but does not have to have sides of equal lengths and can have other shapes. The larger the area of the die substrate168, the more connector systems10,10A,10B,10C can be added to the first die substrate surface172.

FIG.29shows a second die substrate surface180of the die substrate168. The second die substrate surface180can include a second group of cable connector systems10,10A,10B,10C, each electrically connected to the die170(FIG.28). The second die substrate surface180can also define a pin or pad field182that can electrically connect the die170(FIG.28) with a power source, compression connector, pin connector, interposer, etc. (not shown). The compression or pin connector can exclusively include low speed, power, control, or other sideband signals to the die170or can include high-speed signals as well. The second die substrate surface180of the die package174can include serializer/deserializer chips, such as 16-by-16 lane SERDES chips.

As shown inFIGS.28and29, a die package174can therefore include a die substrate168that defines a first die substrate surface172, an opposed second die substrate surface180, a die170included on the first die substrate surface172, cable connector systems10,10A,10B,10C included on the first die substrate surface172, and cable connector systems10,10A,10B,10C included on the second die substrate surface180. Each cable connector system10,10A,10B,10C can include a board connector12included on the first die substrate surface172, a board connector12included on the second die substrate surface180, and a cable connector14releasably connected to each of the board connectors12.

The board connectors12and the cable connectors14can each include one, two, three, or four rows of four differential signal pairs, or any other number of rows, contacts, or differential pairs. For example, each board connector12can include eight differential signal pair per slot, and each cable connector can include eight differential signal pairs, or a total of eight, sixteen, twenty-four, or thirty-two 56 GHz NRZ or 112 GHz PAM4 capable differential signal pairs per cable connector system10,10A,10B,10C. As shown on the 85-mm-by-85-mm die package174, twelve two-row cable connector systems10(FIGS.16and17) can provide at least one hundred and ninety-two differential signal pairs on the first die substrate surface172of the die package174and at least one-hundred and ninety-two differential signal pairs on the opposite second die substrate surface180of the die package174. Twelve four-row cable connector systems10(FIGS.1-10and12-14) positioned on the first die substrate surface172can provide at least three hundred and eighty-four differential signal pairs on the first die substrate surface172of the die package174and at least three hundred and eighty-four differential signal pairs on the second die substrate surface180of the die package174. Any of the cable connector systems can be positioned on a substrate other than a die substrate168.

Cables22attached to the cable connectors14can have a maximum diameter of 33, 34 or 35 or 36 gauge. The board connector12and the cable connector14can both be configured not to receive an edge card. A 2-by-1 board connector12,12A,12B or cable connector14has modeled insertion loss between 0 dB and −1 dB through frequencies up to 25 GHz, modeled insertion loss between 0 dB and −1 dB through frequencies up to 30 GHz, and modeled insertion loss between 0 dB and −2 dB through frequencies up to 40 GHz. Differential return loss can be between −20 dB and −60 dB through frequencies up to 20 GHz and between −10 dB and −60 dB through frequencies up to 30 GHz. Differential far end crosstalk (FEXT) powersum is modeled between −30 dB and −100 dB through frequencies up 40 GHz and between −20 dB and −100 dB through frequencies up to 90 GHz. Modeled differential near end crosstalk (NEXT) is between −40 dB and −100 dB through frequencies up to 35 GHz and between −30 dB and −100 dB through frequencies up to 50 GHz.

A 4-by-1 board connector12,12A,12B or cable connector14has modeled insertion loss between 0 dB and −2 dB through frequencies up to 15 GHz, between 0 dB and −3 dB through frequencies up to 20 GHz, and between 0 dB and −5 dB through frequencies up to 40 GHz. Differential return loss is between −20 dB and −60 dB through frequencies up to 10 GHz and between −10 dB and −60 dB through frequencies up to 50 GHz. Differential far end crosstalk (FEXT) powersum is modeled between −30 dB and −100 dB through frequencies up to 40 GHz and between −20 dB and −100 dB through frequencies up to 60 GHz. Modeled differential near end crosstalk (NEXT) is between −40 dB and −100 dB through frequencies up to 40 GHz and between −30 dB and −100 dB through frequencies up to 50 GHz. Date rata is approximately equal to two times the frequency, so a frequency of 20 GHz approximately equals a data rate of 40 Gbits/sec, a frequency of 30 GHz approximately equals a data rate of 60 Gbits/sec, a frequency of 40 GHz approximately equals a data rate of 80 Gbits/sec, etc.

A panel I/O connector184can include first, second, third, and fourth rows188,190,192,194of electrical conductors, such as eight I/O differential signal pairs196and grounds198arranged in a S-S-G or S-S-G-G configuration. A S-S-G-G configuration can reduce signal density. The first row188and the second row190can be spaced apart by a first pitch P1of about 2.2 mm, the second row190and the third row192can be spaced apart by a second pitch P2of about 3 mm, and the third row192and the fourth row194can be spaced apart by a third pitch P3of about 2.2 mm. Electrical conductors can be on a 0.635-mm pitch. Panel fasteners200can be used to affix the panel I/O connector184to a panel, such as the 1 RU panel202shown inFIG.32. Cables attached to respective differential signal pairs196and grounds can terminate to a respective cable connector14.

FIG.31shows an external cable connector186that can mate with a panel I/O connector184ofFIG.30. The external cable connector186ofFIG.31can include first, second, third, and fourth rows188a,190a,192a,194aof electrical contacts, such as eight I/O differential signal pairs196aand grounds198aarranged in a S-S-G or S-S-G-G configuration. A S-S-G-G configuration can reduce signal density. The first row188aand the second row190bcan be spaced apart by a first pitch P1of about 2.2 mm, the second row190aand the third row192acan be spaced apart by a second pitch P2of about 3 mm, and the third row192aand the fourth row194acan be spaced apart by a third pitch P3of about 2.2 mm. Electrical conductors can be on an about 0.635-mm pitch. Cables22can be electrically connected to the respective differential signal pairs196and grounds198a.

FIG.32shows a surface of a 1 RU panel202populated with panel I/O connectors184. At least thirty-two panel I/O connectors184can fit within the area of a 1 RU panel, which is approximately 1.75 inches by approximately 19 inches, or approximately 29.75 inches2, or approximately 214 cm2.

Embodiments of the present invention can pass or fit at least two-hundred and fifty-seven, at least two-hundred and eighty-nine, at least three hundred, at least four hundred, and at least five hundred 56 GHz NRZ or 112 GHz PAM4 differential signal pairs through a 1 RU panel area. In a 1-by-4 configuration, on a 85-mm-by-85-mm die package, with eight differential signal pairs per slot or row, only twelve board connectors10,10A,10B,10C and only twelve panel I/O connectors are needed on the panel to pass a minimum of three-hundred and eighty-four differential signals through the panel. If twelve more board connectors are positioned on a second die substrate surface of the die package, the total number of differential signal pairs can be doubled to 768 differential signal pairs that pass through less than a 1 RU panel area.

Any 1 RU panel area described herein is not limited to a single 1 RU panel. A 1 RU panel area can be distributed among two or more 1 RU panels. The 1 RU panel can define a plurality of panel through holes, like a screen, to permit airflow through the 1 RU panel.

As shown inFIG.33, for a 1 RU panel optical solution, on-board transceivers204, such as the FIREFLY on-board transceivers produced commercially by SAMTEC, Inc., can be carried by a tray206. Optical front panel connectors208can easily fit within 50% to 60% of a 1.75-inch-by-17-inch area of a 1 RU panel202. Optical front panel connectors208, such as MPO, LC, or SC connectors that are compatible with both multimode optical fiber and signal-mode optical fiber or with high-density optical connectors having optical fibers, each with a 250 μm pitch or smaller, can be optically connected to on-board transceivers204by a respective optical cable210. At least one on-board heat sink212can be positioned between two back-to-back on-board transceivers204. Cooling fans214can move air over the on-board transceivers204and can move air over the on-board heat sinks212. A die package and its corresponding die package heat sink216can be positioned between two linear arrays of on-board transceivers204.

With reference to34, on-board transceivers204can be received by corresponding low speed connectors218and high-speed connectors220that are each positioned on corresponding tray substrates222. This configuration can yield thirty-two on-board transceivers204, sixteen of which are not inverted and sixteen of which are inverted. Cables22are electrically attached to respective ones of the high-speed connectors220at one end, and corresponding cable connector14(FIG.3) at an opposed, second end. Two on-board heat sinks212are shown.

As shown inFIG.35, first, second, and third airflow channels224,226,228can be segregated in a tray206such that on-board transceivers204have discrete, dedicated first and third airflow channels224,228, and the die170, die package174, and die package heat sink (e.g., die package heat sink216inFIG.33) also have a dedicated second airflow channel226. Airflow channels224,226,228can be made by physical partitions230or dedicated cooling fans, heat pipes, etc. The die package174shown inFIG.35is similar to the die package174shown inFIG.28. Separating or segregating first, second, and third airflow channels224,226,228helps to prevent heat spread from the die170and its associated heat sink to the on-board transceivers204, and from the on-board transceivers204to the die170and its associated die package heat sink. The first, second and third airflow channels224,226,228may be parallel to each other, may be positioned immediately adjacent to each other, and may be serviced by separate fans (e.g., cooling fans214inFIG.33). Back-to-back on-board transceivers204may be positioned in the first and third airflow channels224,228. A die170and its associated die package heat sink may be positioned in the second airflow channel226.