High-performance cable terminal

Abstract

The invention relates to a high-performance cable terminal. A cable assembly includes a connector having terminals capable of achieving high density and high signal integrity. The shielding layer of the cable is terminated to the switching card via a conductive structure attached to a surface of the switching card. A signal conductor of the cable terminates to a pad on the switching card exposed within the opening of the conductive structure. Such a structure creates a ground structure for each cable, providing low insertion loss and low crosstalk even in the case where a plurality of cables are arranged side by side and terminated in one or more rows. The cables may be unscrambled so that a large number of cables, such as eight cables, can be wrapped within the width of a switching card specified in a high density standard, such as QSFP-DD or OSFP. Although, the cable may have a signal conductor of large diameter, such that a 2.5 m or 3 m component can have an insertion loss of less than 17 dB.

Description

[0001] This application is a divisional application of the invention patent application with application date of December 16, 2019, application number 201911293124.2, and invention name “High Performance Cable Terminal”. Technical Field

[0002] The technology described herein generally relates to power cable assemblies used to transmit signals between electronic devices such as servers, routers, and switches. Background Art

[0003] The cables are typically terminated at their ends with electrical connectors that mate with corresponding connectors on the electronic device, enabling quick interconnection with the electronic device.

[0004] The cables provide signal paths with high signal integrity, particularly for high frequency signals, such as signals below 28 Gbps using a non-return-to-zero (NRZ) protocol, signals above 50 Gbps using a pulse amplitude modulation (PAM) protocol, etc. Each cable has one or more signal conductors surrounded by a dielectric material, which in turn is surrounded by a conductive layer. A protective jacket, typically made of plastic, may surround these components. In addition, the jacket or other portions of the cable may include fibers or other structures for mechanical support.

[0005] The components of a cable that primarily affect signal propagation, namely the signal conductors, dielectrics, and conductive layers, are typically uniform over the length of the cable. Non-uniformities in the signal path—which may be caused, for example, by variations in the shape or material of a component—cause impedance changes or induce mode conversions, which degrade signal integrity because these effects manifest themselves as insertion loss, crosstalk, or other undesirable effects.

[0006] Flexible signal conductors, dielectric and conductive layers give rise to desirable properties of the cable. This flexibility enables uniform cable properties to be maintained even when the cable is routed with many bends, facilitating signal transmission with high integrity.

[0007] One type of cable, known as a "two-wire cable," is constructed to support the transmission of differential signals and has a balanced pair of signal wires embedded in a dielectric material and surrounded by a conductive layer. In addition to the size of the signal wires being uniform over the length of the cable, the spacing of the signal wires relative to each other and to the conductive layer also remains uniform over the length of the cable because these components are positioned by the dielectric. Such a cable can be formed by extruding a dielectric material around the signal wires.

[0008] The conductive layer is typically formed using a metal foil such as aluminized polyester film or a metal wire braid wrapped around the surface of the dielectric. The conductive layer affects the characteristic impedance of the cable and provides a shielding layer that reduces crosstalk between signal conductors in a pair of cables that may be routed together as a cable bundle. The conductive layer also forms the cable ground reference.

[0009] Two-strand cables can also have drain wires. Unlike signal wires, which are typically coated with a dielectric to prevent electrical contact with other conductors in the cable, drain wires can be uncoated so that they contact the conductive layer at multiple points along the length of the cable. At the end of the cable, where the cable is terminated to a connector or other termination structure, the protective jacket, dielectric, and metal foil can be removed, exposing a portion of the signal wire and drain wire at the end of the cable. These wires can be attached to a termination structure such as a paddle card of a connector. The signal wire can be attached to a conductive element that serves as a mating contact in a connector. The drain wire can be attached to a ground conductor in the termination structure. In this way, any ground return path can be continued from the cable to the termination structure. Summary of the invention

[0010] According to one aspect of the present application, a switching card is provided. The switching card may include a surface, the surface including a plurality of pads on the surface. The switching card may include at least one conductive structure, the conductive structure electrically and physically connected to a pad in the plurality of pads, wherein at least one conductive structure includes a plurality of tabs, each tab extending upward from the surface, and each tab in the plurality of tabs is configured to electrically contact an exposed shielding layer of an associated cable.

[0011] According to another aspect of the present application, a cable assembly is provided. The cable assembly may include a switch card, the switch card including a surface, wherein the switch card includes a first plurality of pads and a second plurality of pads on the surface. The cable assembly may include a plurality of cables, wherein each of the plurality of cables includes at least one conductor and a shielding foil, wherein the conductor in the at least one conductor is electrically and mechanically connected to a pad in the first plurality of pads. The cable assembly may include at least one conductive structure, the at least one conductive structure is electrically and physically connected to a pad in the second plurality of pads, wherein the at least one conductive structure includes a plurality of tabs, and each of the plurality of tabs is at least partially wrapped around a cable in the plurality of cables and electrically connected to the shielding foil of the cable.

[0012] The foregoing is a non-limiting summary of the invention, which is defined by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in different figures is represented by a like reference numeral. For clarity, not every component will be labeled in every figure. In the drawings:

[0014] Figure 1A is an axonometric diagram of a power cable including a drain wire in the prior art;

[0015] Figure 1B It is a prior art that is configured to Figure 1A An axonometric view of a connector for a power cable connection operation;

[0016] Figure 2A is a view of an end portion of an exemplary non-drain power cable;

[0017] Figure 2B is a cross-sectional view of an exemplary non-drain power cable;

[0018] Figure 3A is an isometric view of an exemplary conductive structure according to some embodiments;

[0019] Figure 3B yes Figure 3A A first side view of an exemplary conductive structure;

[0020] Figure 3C yes Figure 3A A second side view of an exemplary conductive structure;

[0021] Figure 4A is a plan view of a surface of an exemplary switching card;

[0022] Figure 4B yes Figure 4A A plan view of an opposite side of an exemplary switching card;

[0023] Figure 5A is a partially exploded view of an exemplary switch card having conductive structures according to some embodiments;

[0024] Figure 5B yes Figure 5A An isometric view of an exemplary switching card having a conductive structure;

[0025] Figure 5C yes Figure 5A An end view of an exemplary switching card having conductive structures;

[0026] Figure 5D yes Figure 5A A side view of an exemplary switching card having conductive structures;

[0027] Figure 5E yes Figure 5AA top view of an exemplary switching card having a conductive structure, wherein two portions are highlighted and enlarged;

[0028] Fig. 6A is an isometric view of a portion of a cable assembly according to some embodiments;

[0029] Figure 6B According to some embodiments Fig. 6A an isometric view of a portion of the cable assembly where the cable is connected to a switch card and a conductive structure;

[0030] Figure 7 is an isometric view of a cable assembly partially cut away, according to some embodiments.

[0031] Fig. 8A is an isometric view of an exemplary switching card having conductive structures according to some embodiments;

[0032] Figure 8B With cable Fig. 8A An isometric view of an exemplary switching card having a conductive structure;

[0033] Fig. 9A illustrates a first exemplary cable harness according to some embodiments;

[0034] Fig. 9B According to some embodiments, Fig. 9A An exemplary cross-sectional view of a cable of a cable bundle;

[0035] Fig. 10A illustrates a second exemplary cable harness according to some embodiments;

[0036] Fig. 10B According to some embodiments, Fig. 10A An exemplary cross-sectional view of a cable of a cable bundle;

[0037] Fig.11 is a performance graph illustrating far end crosstalk for a cable assembly according to some embodiments; and

[0038] Fig.12 is a performance graph illustrating insertion loss for a cable assembly according to some embodiments. DETAILED DESCRIPTION

[0039] The inventors have recognized and appreciated a structure for providing a high frequency, compact cable assembly. The structure may include a conductive structure, such as one or more strips, including a plurality of tabs configured to electrically contact an exposed shielding layer of an associated cable of the high frequency compact cable assembly. The conductive structure may be physically mounted to a surface of a printed circuit board (PCB) such that each tab extends upwardly from the surface of the PCB. The PCB may be a switching card of a connector and may include a plurality of pads at least partially disposed on the surface such that at least one conductive structure is electrically and physically connected to some of the pads.

[0040] The conductive structure can be electrically connected to a ground structure within the PCB, thereby providing a conductive path between the shielding layer of the cable and the grounding structure within the PCB. In some embodiments, the conductive structure can have multiple parts, each part connected to (a) a ground pad of the ground structure, the ground pad is associated with a pair of signal pads of the PCB to which a pair of signal conductors are connected; and (b) a shielding layer of the cable terminated to the pair of signal pads. The part can be configured so that the crosstalk is low at the location where the cable is terminated to the PCB, thereby causing low crosstalk in the cable assembly. The part can be integrally formed of the same conductive material, and for each high-speed cable, there can be an attachment portion to the grounding structure of the printed circuit board. The grounding structure of the PCB can include pads on the surface of the PCB, near or adjacent to the signal pads to which the cable is terminated. Each part can provide a return path for the common mode signal in the cable. The conductive structure can have an opening, exposing the signal pads on the PCB, and promoting close proximity between the signal conductor and the associated return path.

[0041] In some embodiments, the lugs of the conductive structure may include a first group of lugs and a second group of lugs. The first group of lugs may be in a first row, and the second group of lugs may be in a second row parallel to the first row. In some embodiments, the cable assembly may include a plurality of conductive structures. Each conductive structure may be electrically and physically connected to a ground pad of a subset of pads. The plurality of conductive structures may include one or more U-shaped lugs, one or more single-finger lugs at an inner portion of the conductive structure, or both.

[0042] The switch card of the cable assembly may include a signal pad and a ground pad on the surface of the PCB. The cable assembly may include a plurality of cables, each cable including at least one signal conductor and a shielding foil surrounding the signal conductor. The signal conductor may be electrically and mechanically connected to the signal pad. The conductive structure may be electrically and mechanically connected to the ground pad, and each lug may at least partially wrap around the cable to electrically connect to the shielding foil of the cable.

[0043] The end of the cable may include an exposed portion of a shielding foil that at least partially surrounds at least one conductor. In some embodiments, each cable may include at least two conductors and a shielding foil, such as a two-strand cable. The cable may not have a noise suppression wire. The cables may be electrically and physically mounted to the PCB in different rows along the PCB so that the connections for adjacent cables are staggered along the width of the PCB. A row may include cables for sending signals, and a row may include cables for receiving signals. Cables with multiple conductors may be physically and electrically mounted to the PCB, with the conductors for a particular cable mounted side by side on the PCB.

[0044] Termination structures as described herein can provide low crosstalk between signal paths, including low crosstalk between adjacent cable terminations of a row of cable terminations on a switch card. Alternatively or in addition, such a termination structure can provide low crosstalk between a transmit signal path and a receive signal path, which can be terminated in different rows on a switch card. In some embodiments, the far-end crosstalk can be less than 35dB over a frequency range of 1 GHz to 20 GHz. In some embodiments, the far-end crosstalk can be less than 40dB over substantially all frequency ranges, e.g., over 90% of the frequency range. Such crosstalk can be achieved even for compact cable assemblies, such as those compact enough to include switch cards having widths and / or other aspects / dimensions as defined in the OSFP or QSFP-DD standards.

[0045] Alternatively or additionally, a cable terminal as described herein can realize a low-loss cable assembly. For example, a cable assembly can have a cable of 2.5 meters to 3.5 meters in length and have a signal loss of 15dB to 20dB at the Nyquist frequency. As a specific example, the cable assembly can present an end-to-end attenuation of less than 17dB at 13.28GHz with a cable length of 2.5 meters or 3 meters in some embodiments. Such low insertion loss can be achieved by a non-draining cable. One or more conductors in each cable can have a specification between 34 American wire gauge (AWG) and 24AWG, nevertheless, due to the cable terminal technology described herein, these terminals can be compact enough to fit into a switch card with a width as defined in the OSFP or QSFP-DD standard. These technologies can realize closely spaced terminals and use non-draining cables. As a specific example, an OSFP cable assembly supporting signaling up to 56 Gbps may have a cable length of 25 AWG signal conductors, a 100 ohm nominal impedance, with an insertion loss of 17 dB or less at a 3 meter cable length. As another specific example, a QSFP-DD cable assembly supporting signaling up to 56 Gbps per channel may have a cable length of 27 AWG signal conductors and a 100 ohm nominal impedance, with an insertion loss of 17 dB or less at a 3 meter cable length.

[0046] The cable assembly as described herein can be configured to support signals with any suitable electrical bandwidth, such as greater than 20 GHz, greater than 30 GHz, or greater than 40 GHz. For an illustrative example, PAM4 signaling for Ethernet can reach 53.12 Gbps. The baud rate (signaling rate) is 26.56 GBaud. A low-pass filter can be used to intentionally cut off connected devices at 75% of the 26.56 GBaud signaling rate (e.g., to ensure sufficient signal-to-noise ratio). Therefore, the effective achievable bandwidth in GHz is 0.75*26.56 Gbaud=19.92 GHz. The cable assembly described herein can support signaling rates in each of multiple channels.

[0047] Figure 1A A conventional power cable is shown. Power cable 10 - also known as a "two-strand cable" - includes signal wires 11 and 12 covered by dielectric coatings 13 and 14, respectively. In some embodiments, signal wires 11 and 12 can be configured to carry differential signals. The cable also includes a third uncovered wire 15, referred to as a "drain wire." Signal wires 11 and 12 and drain wire 15 are surrounded by a conductive layer 16, which is configured to serve as an electrical shield. Drain wire 15 is in electrical contact with conductive layer 16 at multiple locations along the cable (not shown), thereby maintaining a ground reference with the conductive layer. As shown in FIG. Figure 1AAs shown in , the closing jacket and conductive layer have been removed from the end of the cable to allow for termination.

[0048] Figure 1B A connector 90 configured to terminate one or more cables 10 is shown. The connector 90 includes a circuit board 98 and a grounding portion 95. The grounding portion 95 includes a plurality of openings 96, each of which is configured to receive the cable 10. When the cable 10 is inserted into the opening 96, the signal lines 11 and 12 are in electrical contact with the contact portion 93. In addition, the grounding portion 95 includes a plurality of slots 97, each of which is configured to receive a corresponding drain wire of the cable 10 therein. The grounding portion can be in contact with various drain wires, so that the cable remains grounded and a return path from the switching card to the wire is provided. Although the use of drain wires ensures signal integrity over the entire length of the cable, the additional wires that must be included will increase weight, reduce the flexibility of the cable, take up additional space, etc.

[0049] Figure 2A 2 is a view of an exemplary cable end 202 of a cable 200. The cable 200 may include a pair of signal conductors 204 and 206. As shown, the signal conductors 204 and 206 may extend outwardly at the cable end 202. Any suitable method may be used to configure the end 202 of the cable 200 in this manner. A known technique for terminating a cable is to strip the components of the cable at the end of the cable to expose the signal conductors. According to some embodiments, different components may be stripped to expose different components of the cable. For example, the jacket, conductive layer, and dielectric may be stripped at the end of the cable to expose the signal conductors at the end of the cable. In other areas, only the jacket may be removed to expose the conductive layer.

[0050] Figure 2B 202 is a cross-sectional view of the cable 200 at the end 202. As shown, the signal conductors 204 and 206 can be surrounded by a dielectric material 208, which can be configured to prevent the signal conductors from contacting each other. Alternatively or in addition, the signal conductors can be coated with a dielectric material. The signal conductors 204 and 206 can be formed of copper or formed by copper alloys such as copper zinc, copper nickel, copper magnesium, copper iron, etc. The dielectric material 208 can be enclosed in a conductive layer 209, which can include a foil such as an aluminized polyester film foil or a metal wire braided layer wrapped around the surface of the dielectric material. The conductive layer 209 can be configured to provide shielding to reduce crosstalk between adjacent signal conductor pairs. As shown, the cable 200 can be non-draining because the cable 200 does not include a drain wire in this illustrative embodiment.

[0051] According to one aspect of the present application, a conductive element that provides a ground connection between cables and a PCB to which the cables are terminated can be used to improve electrical properties (e.g., crosstalk) at the termination of cables. As further discussed herein, the conductive element can provide a separate ground path for each cable, which can result in improved electrical properties at the termination (e.g., compared to a connector without the conductive element). Figure 3A is an isometric view of an exemplary conductive structure 300 according to some embodiments. Figure 3B and Figure 3C A side view and an end view of an exemplary conductive structure 300 are shown in accordance with some embodiments. The conductive structure 300 includes a surface 304 extending along a first direction 306 and a second direction 308 . Figure 3B The side surface of the conductive structure 300 when the conductive structure 300 is viewed along the second direction 308 is shown. Figure 3C An end of the conductive structure 300 is shown when the conductive structure 300 is viewed along the first direction 306 .

[0052] Conductive structure 300 includes a plurality of tabs 302, each of which extends upward from a surface 304 of conductive structure 300. In this exemplary embodiment, tabs 302 extend orthogonally to surface 304 and include a bend where the tabs intersect surface 304 of conductive structure 300.

[0053] As combined FIG. 5A to FIG. 5B As discussed, the conductive structure can be designed so that when the conductive structure is mounted to the PCB, the conductive structure is electrically and physically connected to certain portions of the PCB (e.g., ground pads) while not electrically and / or physically connected to other portions of the PCB (e.g., signal pads). To avoid physical contact with these portions, the conductive structure can include openings extending along direction 306 and direction 308. Figure 3A In the example shown in , the conductive structure 300 includes a plurality of openings 310 on the surface 304, and all sides of the openings 310 are defined by the conductive structure 300, so that the conductive structure 300 completely surrounds the openings 310. However, it is not required that the openings be completely surrounded. The conductive structure 300 includes a plurality of openings 322 on the surface 304, and three sides of the openings 322 are defined by the conductive structure 300, so that the conductive structure 300 partially surrounds each of the openings 322, including being surrounded by a protrusion 324 of the conductive structure 300. Although in Figure 3A Not shown, but in some embodiments the conductive structure can completely surround the opening 322 (eg, similar to the opening 310 ).

[0054] As shown in this example, one or more of the openings 310 may include a protrusion 312 extending downwardly into the corresponding opening 310. In some embodiments, the protrusion 312 is used to align the conductive structure 300 to the PCB, for example, by fitting into a hole in the PCB. In some embodiments, the protrusion 312 can be soldered to a ground structure of the PCB.

[0055] In some embodiments, the tabs and openings can be formed and / or arranged in rows of the conductive structure 300. As shown in the exemplary conductive structure 300, the first group of tabs 302 are in a row indicated by arrow 314, and the second group of tabs 302 are in a row indicated by arrow 318, where both rows extend along direction 308. The openings 310 are in a row indicated by arrow 316, and the openings 322 are in a row indicated by arrow 320, where both rows also extend along direction 308. As shown by arrows 314, 316, 318, and 320, the rows are orthogonal to direction 306. Also as shown by arrows 314, 316, 318, and 320, the rows are spaced apart from each other along direction 306.

[0056] The conductive structure may be formed from a metal sheet. For example, the conductive structure may be stamped from a sheet and then the parts may be formed from the metal sheet. FIG. 3A to FIG. 3C The conductive structure 300 includes, for example, a plurality of voids 314 from which a subset of the tabs 302 are punched. The conductive structure may be made of any type of conductive material, such as stainless steel or other metals.

[0057] As discussed herein, the conductive structure can be used in various applications such as for use in standard-based connectors (e.g., for OSFP, QSFP-DD, etc.). The conductive structure can be mounted (e.g., soldered) to the PCB before the cable is connected, used as a switch card in the plug connector, so that the conductive structure is located between the cable and the PCB. The conductive structure can be used to provide a separate grounding path for a cable, such as a cable without a drain pad. Some standards specify the dimensions of various aspects of the connector, such as the size of the switch card, the number, size, and position of the solder pads, etc. The conductive structure discussed herein can be used to provide a separate grounding path for a cable without a drain wire, which can reduce crosstalk between connector cables. Being able to omit the drain wire from the cable while still providing sufficient electrical properties at the termination can make the cable thinner, enable the use of thicker (e.g., lower gauge) wires (e.g., to achieve less loss than thinner wires), and / or both.

[0058] Figure 4A is a plan view of a first side 402 of an exemplary switching card 400, and Figure 4B4 is a plan view of opposite sides 404 of an exemplary switch card 400. The switch card extends along a first direction 450 and a second direction 452. At least at the mating interface where the contact pads 406 are located, the width of the switch card 400 (shown here as along the second direction 452) can be specified by an associated standard. For example, in some embodiments, the width can be between 13.25 mm and 19.75 mm, between 19.5 mm and 29 mm, etc. In many commercial applications, the switch card will have the same width throughout its length.

[0059] Each side 402 and 404 has FIG. 4A to FIG. 4B 4 and 5. The side surfaces 402 and 404 also have solder pads 410 and 412. These pads may be implemented in a variety of ways, such as by being disposed over a metal layer on the surface of the switch card 400 or otherwise connected to or as the top of a via within the switch card 400.

[0060] Solder pads 410 are arranged along two rows as indicated by dashed arrows 422A and 422B, and solder pads 412 are similarly arranged along two rows as indicated by dashed arrows 426A and 426B. As with contact pads 406 and 408 discussed below, solder pads 410 and solder pads 412 include multiple groups of solder pads. There can be one group of solder pads per cable. Figure 4A A first group of welding pads J2 including signal welding pads 410A and 410B and a ground welding pad 410C disposed to the right of the signal welding pads 410A and 410B is shown. In this exemplary embodiment, the welding pads 410A, 410B, and 410C are respectively used to electrically and physically connect to a pair of signal lines (represented as "N" and "P" in the figure) of an associated transmission cable (e.g., a first transmission cable) and ground. Figure 4A Also shown is a second group of welding pads J4 including signal welding pads 410D and 410E and a ground welding pad 410F disposed on the right side of the signal welding pads 410D and 410E. In this exemplary embodiment, welding pads 410D, 410E, and 410F are respectively used to electrically connect and physically connect to the N and P signal lines and ground of the associated transmission cable (e.g., the third transmission cable). The ground welding pads and paired signal welding pads in each row can be alternated. For example, the pair of signal welding pads 410D and 410E are disposed between ground welding pads 410C and 410F, and ground welding pad 410C is disposed between signal welding pad pair 410A / 410B and 410D / 410E.

[0061] In some embodiments, the switching card 400 can be configured such that at least one of the ground solder pads adjacent to a pair of signal pads is attached to a portion of a ground structure within the switching card, and the traces attached to the pair of signal pads are referenced to a portion of the ground structure. For example, if there is a common mode signal on a pair of traces, there will be a corresponding return current flowing through the ground structure that these traces are referenced to. For example, in a switching card, the ground planes can be interleaved between layers carrying signal traces so that the traces are referenced to an adjacent ground plane, which can be the ground plane closest to the traces.

[0062] Contact pads 406 and 408 are electrically connected to welding pads 410 and 412, respectively, through the interior of the switch card. For example, a trace within the switch card connects welding pad 410A to contact pad 406A; a second trace within the switch card connects welding pad 410B to contact pad 406B; and a ground plane within the switch card can connect welding pad 410C to contact pad 406C. As another example, a third trace can connect welding pad 410D to contact pad 406D; a fourth trace can connect welding pad 410E to contact pad 406E. The same or different ground plane can connect welding pad 410F to contact pad 406F. Therefore, like welding pads 410 and 412, contact pads 406 and 408 can be logically grouped into contact pad groups associated with cables terminated to the switch card.

[0063] For example, each set of contact pads in contact pads 406 may include a pair of signal pads and a ground pad that facilitates connecting a signal from an associated cable to a corresponding contact of a mating connector. Figure 4A A first set of contact pads is shown including signal contact pads 406A and 406B and ground contact pad 406C. In the illustrated embodiment, ground contact pads, such as 406C, are longer than signal contact pads, such as contact pads 406A and 406B. Figure 4A Also shown is a second set of contact pads including signal contact pads 406D and 406E and ground contact pad 406F. Figure 4A and Figure 4B Other contact pads are shown that are not numbered for simplicity. Contact pads 406 are arranged along two rows indicated by dashed arrows 420A and 420B, and contact pads 408 are similarly arranged along two rows indicated by dashed arrows 424A and 424B. Each row includes multiple contact pad groups.

[0064] The ground contact pads and pairs of signal contact pads in each row can alternate. For example, a pair of signal contact pads 406A and 406B are disposed between ground contact pads 406C and 406F, and ground contact pad 406F is disposed between signal pairs 406A / 406B and 406D / 406E. As shown, there is a space (e.g., Figure 4A In some configurations, a prewipe pad may be disposed between rows of contact pads 406 and 408 or may be disposed between some or all of the contact pads in a row near an edge of a paddle card and the edge (e.g., as in FIG. 5A to FIG. 5B ).

[0065] Although in FIG. 4A to FIG. 4B Although not shown, active components may be attached to switch card 400. For example, switch card 400 may be sized to be sufficient to allow active components to be attached to the switch card 400. Figure 4A 420A and the row of contact pads 422B shown in FIG. 420B are attached to the switch card 400. For example, filters, amplifiers, transceivers, etc. are examples of active components that can be attached to the switch card 400. For example, in some applications, it may be desirable to convert the communication protocol used on the cable to a different communication protocol (e.g., to convert between different communication standards). Active components can be included on the switch card 400 to perform the conversion on the switch card 400 so that different protocols are provided to the mating connector.

[0066] In some embodiments, the conductive structure can be electrically connected and physically mounted to solder pads on either or both sides of the switch card. In particular, as further discussed herein, the conductive structure can be sized to be electrically and physically connected (e.g., by soldering) to the ground solder pads of the switch card. Figure 5A is a partially exploded view of an exemplary paddle card 500 having conductive structures 502 and 504 in accordance with some implementations. Paddle card 500 may be configured similarly to paddle card 400 except for having a different configuration of contact pads.

[0067] As shown in this example, conductive structure 504 is mounted to the bottom side of switch card 500. Conductive structure 502 is electrically and physically connected to ground solder pad 506 on the top side of switch card 500. 5B is an isometric view of an exemplary switch card 500 showing conductive structure 502 electrically and physically connected to switch card 500. Since conductive structure 502 is connected to switch card 500, Figure 5A The ground solder pad 506 in Figure 5B Not visible in. Figure 5BThe use of dashed area 508 highlights where the conductive structure 502 is electrically and physically connected to the ground solder pad 506 .

[0068] Figure 5C is a first side view of a switch card according to some implementations. Figure 5C 4 is a view of an end of the paddle card 500 when viewing the side of the paddle card 500 opposite the side where the conductive structures 502 and 504 are connected to the paddle card 500 along the first direction 450 . Figure 5D is a side view of a switch card 500 according to some implementations. Figure 5D 4 is a view along the second direction 452 of the left side of the switch card. As shown, the lug 504 extends orthogonally to the surface of the conductive structure and includes a bend 504A at the location where the lug 504 intersects the surface of the conductive structure. Figure 5C and 5D As shown in FIG. 5 , conductive structures 502 and 504 are mounted on respective sides 501A and 501B of paddle card 500 at locations opposite to each other.

[0069] In some cases, it may be desirable to control electrical properties of a cable assembly such as far-end crosstalk. Crosstalk and other undesirable electrical properties may result from the way the cable assembly is terminated to a switch card. When a cable including a signal wire and a drain wire (or shield) is connected to a switch card, a mechanical discontinuity must occur. For example, if a cable is connected to a switch card, a Figure 2A As discussed, in order to connect a cable (e.g., at a solder pad) to a switching card, layers of the cable (e.g., a conductive layer and a dielectric coating applied to the signal line) are removed so that the ends of the signal lines can be connected (e.g., soldered) to the switching card. This discontinuity may cause one or more effects that affect the integrity of the signal passing through the cable assembly. For example, the propagation mode of some signal energy carried by the cable may change so that not all energy in the signal cable will be transferred to the switching card (and vice versa). Some of the energy that is not transferred to the switching card may be radiated, causing crosstalk. In addition, mechanical discontinuities may create the possibility of signal reflections, which may cause further attenuation because the signal energy propagates backward through the signal line instead of entering the switching card.

[0070] The conductive structure can be configured to provide a cable terminal with little effect on signal integrity. The conductive structure can include a portion that creates a separate ground path for each cable (e.g., for each pair of signal lines). The conductive structure can be shaped and positioned to act as the closest ground conductor to the signal conductor of the cable or the connector of the terminated cable. The conductive structure can be shaped to provide a ground path for each cable or each signal pair. The conductive structure is connected to the ground portion of the cable (e.g., the shielding layer of the cable). In addition, the conductive structure can be shaped and positioned to provide space between the signal conductor and the closest ground in the cable terminal to smooth any impedance transition between the traces to which the signal conductors in the cable and the switching card are connected. The conductive structure can be shaped and positioned to provide an impedance in the signal path at the termination, which is close to the impedance in the signal conductor or the impedance in the trace or is transformed between the impedance of the cable and the impedance of the switching card. Alternatively or additionally, the conductive structure can be shaped and positioned to be close to the space between the signal conductor and the closest ground in the cable relative to the signal path.

[0071] Alternatively or additionally, the conductive structure can be shaped and positioned to provide a separate ground path for each signal conductor or pair of signal conductors that is proximate to a separate ground path for the signal conductor that exists within the cable. For example, for a two-strand cable without a drain wire, the lugs of the conductive structure are mechanically and electrically connected to the exposed shield of the cable of the assembly to complete the conductive path from the cable shield to the ground structure of the switching card. The connection can be made part of the ground structure, and the traces in the switching card that are coupled to the signal conductors of the same cable are referenced to a portion of the ground structure. The separate ground paths can reduce crosstalk because the ground return path of the cable terminated to the switching card is less coupled.

[0072] Figure 5E is a top view of an exemplary switch card 500 having conductive structures 502 mounted to side 501A according to some embodiments. Figure 5B Similarly, since the conductive structure 502 is connected to the switch card 500, Figure 5E The center ground pad is not visible. Figure 5E Arrow 554 is used to illustrate the location where the conductive structure 502 is electrically and physically connected to the ground solder pad 506 (for clarity and simplicity, Figure 5B The dashed area 508 used in FIG. 5 is not included in the Figure 5E). Conductive structure 502 includes multiple portions that create separate ground paths for associated signal pads, two of which are shown as portions 550 and 570. Each portion is electrically and physically connected to a ground solder pad adjacent to an associated pair of signal solder pads. For example, portion 550 is electrically and physically connected to the ground solder pad at the portion shown by dashed areas 552A and 552B, and in particular, the ground pad at area 552A is associated with signal pads 558 and 560. Portion 570 is electrically and physically connected to the ground solder pad at the portion shown by dashed areas 572A and 572B, and in particular, the ground pad at area 572B is associated with signal pads 578 and 580. Each portion also includes a tab that is aligned with a pair of signal pads, such as in combination FIG. 6A to FIG. 6B As discussed herein, the lug is configured to electrically contact the exposed shield of a cable terminated to a corresponding pair of signal pads. For example, portion 550 includes a lug 556 aligned with a pair of signal pads 558 and 560. Portion 570 includes a lug 576 aligned with a pair of signal pads 578 and 580. Thus, in some embodiments, each portion can be associated with a return path from a switching card to a cable having a signal conductor electrically connected and physically connected to a pair of signal pads within the portion. As further discussed herein, when assembled, the lug aligned with a pair of signal pads is folded over the shield of the line to complete the conductive path between the shield of the cable and the ground structure within the switching card via a portion of the conductive structure.

[0073] Fig. 6A 6 is an isometric view of a portion of a cable assembly 600 according to some implementations. Cable assembly 600 includes a plurality of cables 602 (sixteen cables in this illustrative example). Cable assembly 600 includes a switch card 604 having two conductive structures 606 and 608. Figure 6B6 is an axonometric view of a portion of a cable assembly 600 in which a cable 602 is connected to a switch card 604 and a conductive structure 606. For each cable, the end of the signal line is welded to a corresponding signal welding pad. For example, for cable 602A, the end of the first signal line 610A is welded to the first signal welding pad, and the end of the second signal line 610B is welded to the second signal welding pad. The conductive structure 606 also includes a plurality of lugs 614A, each of which is folded onto the shielding layer of the corresponding cable. For example, the lug 614A is folded onto the exposed shielding layer of the cable 602A so that the lug is in physical and electrical contact with the shielding layer. The lug can be bent around the shielding layer of the cable using a tool, for example, that is configured to fully bend and press each lug so that the lug is in physical and electrical contact with the shielding layer without damaging the cable or the conductive element (for example, without crushing the cable). Pressing the lug into a shape consistent with the shape of the cable when the shielding layer is exposed can provide sufficient coupling between the conductive member and the shielding layer of the cable. In other embodiments, attachment materials may be added including conductive adhesives or solders.

[0074] As combined Figure 5E Discussed, the conductive structure includes a part for providing a ground path for each cable for each cable. For example, part 612 of the conductive structure 606 creates a ground path for the cable 602A. These ground paths are mostly or completely disjoint, thereby reducing the crosstalk between the cables. Although not bound by any specific theory of operation, the inventor believes that molding the conductive structure in this way reduces mode conversion and impedance discontinuity. It is also believed that the ground paths that are mostly or completely disjoint reduce the crosstalk between the cables. The conductive structure can be molded to enable the cable to be connected to the different rows (for example, a row of all transmission signals, and another row of receiving signals) of the switching card. Using multiple rows can also help reduce the crosstalk effect, because the cables can be grouped into multiple rows by signal level (for example, a higher transmission signal can be grouped in a row, and a lower reception signal can be grouped in another row), so that further isolation can be achieved between cables with different signal levels (for example, to avoid crosstalk drowning (overwhelming) lower signal cables). The ground paths through the conductive structure associated with cables in separated rows are completely non-intersecting, which provides good electrical isolation between conductors that have a high potential for generating harmful crosstalk (e.g., crosstalk from a cable with a higher signal level in one row that could have a substantial effect on a lower level signal carried by a conductor in another row).

[0075] Figure 7700 is an isometric view of a cable assembly 700 according to some embodiments. The cable assembly 700 includes outer portions 702 and 704 of a plug housing, and the outer portions 702 and 704 are fixed to each other using screws 706. The outer portions 702 and 704 surround a switch card 708, which includes conductive structures and cable terminals, such as a combination of FIG. 6A to FIG. 6B As discussed. The cable assembly 700 includes two cable bundles 710. In area 712, the signal lines and other portions of the cables of the cable assembly 700 are cut away for illustrative purposes. The cable assembly 700 also includes a lug 714 connected to a latch release member 716, which can be pulled to release the latch of a cage into which the cable assembly 700 can be inserted, so that the cable assembly 700 can be removed from the cage. The cable assembly 700 includes a stabilizing portion 718, which is used to hold the cable relative to the switch card 708 to reduce strain on the cable terminals that may be caused by forces on the cable. The stabilizing portion 718 can also provide a housing to facilitate the installation of the switch card 708 in the plug housing. The cable assembly 700 also includes a removable cover 720.

[0076] In some embodiments, the connector modules can be attached to cables to create a cable assembly that can be used to connect electronic devices. Each module can include one or more conductive members to terminate one or more cables in the above manner. The module can include a mating contact portion configured to mate with a mating contact portion in a mating connector. In the illustrated embodiment, the mating contact portion is rectangular and at the end of the switch card. The mating contact portion can include a signal pad and a ground pad, and can be configured to mate with a mating contact portion in a socket.

[0077] The plug of the cable assembly 700 can be mated with a socket connector installed in an electronic device. For example, the socket connector can be installed on a printed circuit board (PCB) in the electronic device. The cable assembly 700 can be configured to connect any suitable electronic device to any other suitable device, such as connecting a first computer to a second computer, connecting a computer to a server, etc. The cable assembly 700 including the cables of the cable bundle 710 can have characteristics selected for the type of signals transmitted between the connected devices.

[0078] Fig. 8A is an isometric view of an exemplary switch card 800 having conductive structures 802 according to some embodiments. Figure 5A Compared to an embodiment, for example, in which the conductive structures on each surface of the switching card are integral components, Fig. 8A The conductive structure in the embodiment has a conductive structure formed by multiple separate members attached to each surface of the switch card.

[0079] The first side 806 of the switch card 800 has four conductive structures 802. Although not shown, in the illustrative embodiment, the opposite side (the bottom side opposite the side 806) also has four conductive structures 802. The switch card 800 includes welding pads 804 in a first row 808 and a second row 810. The first row 808 and the second row 810 extend along a second direction 814 orthogonal to the first direction 812 and are spaced apart in the first direction 812. The conductive structures 802 are electrically connected and physically connected to the switch card 800, so that two conductive structures 802 are in the third row 816 and two conductive structures 802 are in the fourth row 818. The third row 816 and the fourth row 818 extend along the second direction 814 and are spaced apart from each other along the first direction 812. The conductive structures 802 are electrically connected and physically connected to the switch card 800 through corresponding ground pads in the rows 816 and 818. Alternatively, each conductive structure 802 can be electrically connected and physically connected to the switch card 800 through a single ground pad. In some implementations, each conductive structure 802 is electrically and physically connected to the paddle card 800 through a plurality of ground pads.

[0080] Each conductive structure 802 includes tabs arranged along a row to which the conductive structure 802 is electrically and physically connected. For example, the conductive structure 802A includes four tabs 820A to 820D along the row 818. Tabs 820A and 820D are formed at respective ends of the conductive structure 802A, respectively, and are U-shaped. Tabs 820B and 820C include single fingers formed at the interior of the conductive structure 802A. The tabs of the conductive structure 802 extend upward in a direction orthogonal to the surface of the first side 806. The tabs of the conductive structure 802 include a width extending along the first direction 812.

[0081] Each conductive structure 802 includes a plurality of portions such as portion 840 (e.g., two portions). Each portion is connected to a ground pad of a ground pad structure of a switching card 800. Each portion is associated with a pair of signal pads (e.g., signal pads 804A and 804B for portion 840) to which a pair of signal conductors are connected. Each portion is connected to a shielding layer of a cable terminated to the pair of signal pads, including connections through finger-shaped tabs and U-shaped tabs of the portion. The portion can be configured such that crosstalk is low at the location where the cable is terminated to the PCB, resulting in low crosstalk in the cable assembly.

[0082] Figure 8B 8 is an isometric view of an exemplary switching card 800 having a conductive structure 802 and a cable 850. As discussed herein, the tabs of the conductive structure are configured for electrical and physical connection to the shielding layer of the cable. Figure 8B8. The conductive structure 802 is shown both before and after being connected to the conductive shielding layer of the cable. For example, the conductive structure 802B is shown before its associated tabs are connected to the conductive shielding layer of the cables 850A and 850B, while the conductive structure 802A is shown with its associated tabs 820A to 820D in physical and electrical contact with the conductive shielding layer of the cables 850C and 850D. As shown for the conductive structure 802A, each pair of adjacent U-shaped tabs and single-finger tabs (e.g., a pair of U-shaped tabs 820A and single-finger tabs 820B) is configured for connection to the same cable such that when the pair of tabs is folded around the cable, the single-finger tab is disposed within the U-shaped tab.

[0083] Each of the conductive structures 802 includes a space portion separating the tabs in each pair, such as Fig. 8A The space 822 between the lugs 820C and 820D shown in FIG. The space portion separating each pair of lugs is dimensioned along the second direction 814 to be wide enough to accommodate a cable, such as Figure 8B 820D). Each of the conductive structures 802 also includes a space portion disposed between the two pairs of lugs (eg, Fig. 8A The space portions between each pair of tabs are sized along the second direction 814 to be wide enough to allow a cable to pass therethrough, depending on the row (e.g., row 816 or 818) in which the conductive structure is mounted to the switch card. For example, Fig. 8A and Figure 8B As shown in , the conductive structure 802 in row 816 includes cables that pass through the conductive structure but are not connected to the conductive structure, so that the cables can be mounted to the switching card in parallel in a manner such that adjacent cables are connected to solder pads in different rows (e.g., rows 808 or 810).

[0084] Although FIG. 6A to FIG. 8B Although not shown, in some embodiments, a fastening element may be included in the cable assembly (e.g., as part of a connector) to keep the lug in electrical and physical communication with the cable shield. The fastening element may be sized to be sufficient to keep the lug in electrical and physical communication with the cable without damaging the cable and / or the lug. The fastening element may be made of a dielectric material such as a plastic or rubber material.

[0085] Various types of cables and / or cable bundles can be used with the techniques discussed herein. The inventors have discovered techniques that enable the use of lower gauge wires that will have less loss in the cable while still maintaining the same (if not smaller) cross-sectional area as compared to cables with higher gauge signal conductors. For example, as the frequency of a signal passing through a cable increases, the attenuation of that signal may also increase. Therefore, while a lower gauge wire may be larger than a higher gauge wire, the lower gauge wire may allow for higher frequency applications or longer cable assemblies because the lower gauge wire may provide better attenuation at such frequencies.

[0086] The cable assemblies described herein can be designed to provide cables of a specific length that provide specific cable characteristics (e.g., impedance, frequency, loss, etc.), even in the case where the space available for terminating the cable is limited by the standard of the switching card resulting in a limited width. For example, it may be desirable to provide a three (3) meter long, end-to-end 100 ohm cable with only 17 dB loss via the use of 25AWG or 27AWG signal conductors. The configuration of the cable and / or cable bundle can be designed to achieve such cable characteristics and the technology described herein can be used to terminate such cables to a switching card of limited width. In some embodiments, the cable can be constructed without a drain wire and the size and type of dielectric material around the signal conductor can be selected to provide a cable of a width that can be terminated to the switching card according to high-density standards. However, it should be understood that the size of the dielectric material cannot be arbitrarily changed to meet the mechanical (e.g., size) requirements of the standard because the choice of material size may affect other cable characteristics such as impedance. Nevertheless, the inventors have achieved the desired size and electrical characteristics of the cable assembly using the technology described herein.

[0087] FIG. 9A to FIG. 9B A first exemplary cable harness 900 according to some embodiments is shown. Cable harness 900 includes eight cables 902, each cable having a corresponding pair of signal conductors. For example, cable 902A includes signal conductors 904A and 904B. The signal conductor can be made of various conductive materials. For example, the signal conductor can be made of copper, silver, gold, plated copper (plated copper) (e.g., silver-plated copper), copper alloys (e.g., such as copper zinc, copper nickel, copper magnesium, copper iron, etc.). The signal conductor can have various specifications, such as specifications ranging from about 34AWG to 27AWG. For example, for a cable assembly that meets the QSFP-DD standard, the wire can be 34AWG to 27AWG (e.g., in other aspects, other signal conductors are typically 34AWG to 25AWG or higher).

[0088] Each signal conductor is surrounded by a dielectric material. For example, signal conductors 904A and 904B of cable 902A are each surrounded by dielectric materials 906A and 906B, respectively. The dielectric material can be made of any dielectric such as a polymer (eg, a foamed fluorinated polymer).

[0089] For each cable, the signal conductors and associated dielectrics are surrounded by a conductive foil. For example, cable 902A surrounds signal conductors 904A, 904B and associated dielectric materials 906A, 906B by conductive foil 908. The conductive foil can be made of any conductive material such as aluminum, aluminum-coated polyester (e.g., aluminized polyester film), wire braid, etc. The conductive foil can also include additional layers such as a transparent polyester layer above the conductive foil.

[0090] Various groups of cables and / or cable layers may be surrounded by a buffer layer. For example, in the cable bundle 900, two buffer layers 910A and 910B are included. The buffer layer may be made of tape such as polyolefin or polyester tape. Each cable bundle may include one or more outer shielding layers. The cable bundle 900 includes an inner shielding layer 912 and an outer shielding layer 914. The inner shielding layer 912 may be made of a conductive material such as aluminum, aluminum-coated polyester, etc. The outer shielding layer 914 may be made of a braided material such as a copper braid, a tinned copper braid, etc. The wires used in the braid may have various specifications such as 36AWG to 40AWG, such as 38AWG. The outer jacket 916 may be a protective material such as PVC, polyester, etc.

[0091] like Fig. 9B As shown in , for the exemplary cable 902A, the signal conductors 904A, 904B, the dielectric materials 906A, 906B, the conductive foil 908, and the outer coating (e.g., transparent polyester, if present) can be configured to achieve specific dimensions for each cable. A first dimension 950 in the vertical direction can be in the range of 1.25 mm to 1.6 mm, for example, 1.40 mm. A second dimension 952 in the horizontal direction can be 2.5 mm to 2.7 mm, for example, 2.62 mm. As shown in FIG. FIG. 9A to FIG. 9B The cable design shown in can achieve an impedance of, for example, 100 ohms and support signals up to 23 GHz.

[0092] FIG. 10A to FIG. 10B A second exemplary cable bundle 1000 is shown according to some embodiments. The cable bundle 1000 includes eight cables 1002, each cable having a corresponding pair of signal conductors. FIG. 9A to FIG. 9BSimilar to the cables in FIG. 1 , cable 1002A includes signal conductors 1004A and 1004B, dielectric materials 1006A and 1006B, conductive foil 1008, buffer layers 1010A and 1010B, inner and outer shield layers 1012 and 1014, and outer jacket 1016. The signal conductors in the exemplary cable bundle 1000 may be approximately 25 AWG to 34 AWG, such as 27 AWG.

[0093] like Fig. 10B As shown in , for the exemplary cable 1002A, the signal conductors 1004A, 1004B, the dielectric materials 1006A, 1006B, the conductive foil 1008, and the outer coating (e.g., transparent polyester, if present) can be configured to achieve specific dimensions for each cable. A first dimension 1050 in the vertical direction can be 1.05 mm to 1.25 mm, such as 1.17 mm. A second dimension 1052 in the horizontal direction can be 2.05 mm to 2.25 mm, such as 2.16 mm. As shown in FIG. FIG. 10A to FIG. 10B The cable design shown in can achieve an impedance of, for example, 100 ohms and support signals up to 23 GHz.

[0094] The technology disclosed herein can be used, for example, for data rate applications specified by the IEEE 802.3cd 56Gbps / lane PAM4 Ethernet standard, the entire contents of which are incorporated herein by reference. An external I / O cable assembly with a test card using a conductive structure as discussed herein was built in accordance with the IEEE 802.3cd standard for testing. The test card signal conductors were 27AWG, and the test card complied with QSFP-DD. The test card used two ground clips, one on each side of the switch card.

[0095] Fig.11 1 is a performance graph 1100 showing far-end crosstalk (FEXT) for a test assembly according to some embodiments. Performance graph 1100 shows the FEXT for the eighth receive line (RX8) of side P2 (one of the ends of the cable assembly, where P1 refers to the other end of the cable assembly) when each of the first to seventh transmit lines (TX1 to TX7) is driven. Performance graph 1100 shows curves for TX1 to TX7 over a frequency range of 0 GHz to 26.5 GHz. As shown in graph 1100, the FEXT of the transmit lines is substantially less than 40 dB over a frequency range of 0 GHz to 26.5 GHz (e.g., for more than 90% of the frequency range), with the crosstalk of most transmit lines being less than 40 dB over this range. For TX1, the worst-case crosstalk exceeds 40 dB by only a few dB (e.g., less than 2 dB) for a sub-range of smaller frequencies.

[0096] Fig.121 is a performance graph 1200 showing differential insertion loss (SDD21) or insertion loss (IL) for a test assembly according to some embodiments. Performance graph 1200 shows the IL for lines 1 to 8 when transmitting from both side P1 to side P2 and from side P2 to P1. For example, P1TX1-P2RX1 shows the differential insertion loss from side P1 on TX1 to the RX end of line TX1 (P2RX1) at side P2. As another example, P2TX1-P1RX1 represents a transmission from side P2 on TX1 to side P1 (P1RX1) which is the RX end of line TX1. Performance graph 1200 shows traces for each transmission over a frequency range of 0 GHz to 27 GHz. Performance graph 1200 also shows the maximum IL for 802.3cd. As shown in graph 1200, for both transmit and receive signaling, IL increases with frequency, starting near 0 and increasing to an IL between approximately 27 dB and 36 dB, with one line showing the IL slightly exceeded by a small amount (e.g., a few dB) near 25 GHz.

[0097] like Figure 11 to Figure 12 The crosstalk and IL shown in reveal a cable assembly that is well suited for high frequency signals including signals in the range of 0 GHz to 27 GHz in an assembly having multiple channels, such as an assembly that meets the OSFP or QSFP-DD standards. Such a cable assembly can, for example, meet the QSFP-DD standard, with a 27 AWG signal conductor of 2.5 meters, with an end-to-end attenuation of less than 17 dB. As another example, the cable assembly can meet the OSFP standard, with a 25 AWG signal conductor of 3.0 meters, with an end-to-end attenuation of less than 17 dB.

[0098] Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art.

[0099] For example, embodiments are described that meet the requirements of the OSFP and QSFP-DD standards. The techniques described herein can be applied to cable assemblies that meet other standards or custom configurations that are not designed for a specific standard.

[0100] Similarly, embodiments are described for a double density configuration where the contact pads on the switch card are arranged in two rows. The same techniques can be used in other configurations, including switch cards with a single row or more than two rows of contact pads and / or solder pads.

[0101] As another example, a circular cable bundle is shown. The techniques described herein can be used with ribbon cables or cable bundles in other configurations. Likewise, the cable is described as having two signal conductors wrapped with a shield. Other cable configurations such as a ribbon cable can be used, where two shielding films are sandwiched on either side of each of multiple groups of signal conductors.

[0102] These changes, modifications and improvements are intended to become a part of the present disclosure, and are intended to fall within the spirit and scope of the present invention. In addition, although the advantages of the present invention have been pointed out, it should be understood that not every embodiment of the present invention will include each advantage described. Some embodiments may not realize any feature described as being advantageous in this article and in some examples. Therefore, the above description and accompanying drawings are only used as examples.

[0103] The various aspects of the present invention can be used alone, in combination, or in various arrangements not specifically discussed in the embodiments described above, and therefore the application of the present invention is not limited to the details and arrangements of the components set forth in the preceding description or shown in the accompanying drawings. For example, the aspects described in one embodiment can be combined in any manner with the various aspects described in other embodiments.

[0104] In addition, the present invention can be implemented as a method, examples of which have been provided. The actions performed as part of the method can be ordered in any suitable manner. Thus, embodiments can be constructed in which the actions are performed in a different order than shown, which can include performing some actions simultaneously, even though shown as sequential actions in illustrative embodiments.

[0105] Furthermore, the depicted and described circuits and modules may be re-ordered in any order, and signals may be provided to enable corresponding re-ordering.

[0106] Computer executable instructions can take various forms such as program modules that are executed by one or more computers or other devices. Typically, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. Typically, the functions of program modules can be combined or distributed as needed in various implementations.

[0107] In addition, the data structure can be stored in a non-transient computer-readable storage medium in any suitable form. To simplify the description, the data structure can be shown as having a field related to the position in the data structure. Such a relationship can also be realized by distributing the storage of the relationship between the fields transmitted by the field with the position in the non-transient computer-readable medium. However, any suitable mechanism can be used to establish the relationship between the information in the fields of the data structure, including the use of pointers, tags or other mechanisms that establish relationships between data elements.

[0108] The use of ordinal terms such as "first," "second," "third," etc. in the claims to modify claim elements does not in itself imply any priority, precedence or sequence of one claim element relative to another claim element or the temporal order of the acts of performing the method, but merely serves as a label to distinguish one claim element with a particular name from another element with the same name (but used in ordinal terms) to distinguish the claim elements.

[0109] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0110] Unless expressly indicated to the contrary, the indefinite articles "a" and "an" as used herein in the specification and claims should be understood to mean "at least one.

[0111] As used herein in the specification and claims, when referring to a list of one or more elements, the phrase "at least one" should be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements, and not excluding any combination of elements in the list of elements. This definition also allows that elements other than the elements specifically identified in the list of elements to which the phrase "at least one" is referenced may optionally be present, whether related or unrelated to those elements specifically identified.

[0112] As used herein in the specification and claims, the phrase "and / or" should be understood to mean "either or both" of the elements so combined, i.e., elements that are present in combination in some cases and separately in other cases. Multiple elements listed with "and / or" should be interpreted in the same manner, i.e., "one or more" of the elements so combined. Other elements may optionally be present in addition to the elements specifically identified by the "and / or" phrase, whether related or unrelated to those specifically identified elements. Thus, as a non-limiting example, when used in conjunction with open language such as "comprising", a reference to "A and / or B" may refer to only A (optionally including elements other than B) in one embodiment; to only B (optionally including elements other than A) in another embodiment; to A and B (optionally including other elements) in yet another embodiment; etc.

[0113] As used herein in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating the items in the list, "or" or "and / or" should be interpreted as inclusive, i.e., including at least one, and including more than one in a plurality of elements or a list of elements, and optionally including other unlisted items. Only explicitly indicating the terms opposite thereto such as "only one of..." or "exactly one of..." or when using "consisting of..." in the claims will refer to including exactly one element in a plurality of elements or a list of elements. Usually, the term "or" used herein should only be interpreted as indicating exclusive alternatives (i.e., "one or the other but not both") before exclusive terms such as "any one", "one of...", "only one of..." or "exactly one of...", and should have its ordinary meaning used in the field of patent law when used in the claims.

[0114] In addition, the words and terms used herein are for descriptive purposes and should not be considered limiting. The use of "includes," "comprising," or "having," "containing," "involving," and variations thereof herein is meant to encompass the items listed thereafter and their equivalents as well as other items.

[0115] In addition, the present disclosure also provides the following configuration.

[0116] 1. A switching card, comprising:

[0117] a surface comprising a plurality of pads on the surface; and

[0118] at least one conductive structure electrically and physically connected to a pad of the plurality of pads, wherein:

[0119] The at least one conductive structure includes a plurality of tabs, each tab extending upwardly from the surface; and

[0120] Each lug of the plurality of lugs is configured to make electrical contact with an exposed shielding layer of an associated cable.

[0121] 2. The switching card according to configuration 1, wherein:

[0122] The plurality of pads include pairs of signal pads and ground pads disposed between adjacent pairs of signal pads; and

[0123] The at least one conductive structure comprises a plurality of parts, each part:

[0124] electrically and physically connected to a ground pad of the plurality of pads adjacent to a corresponding pair of signal pads of the plurality of pads; and

[0125] A lug of the plurality of lugs is included that is aligned with the corresponding pair of signal pads to electrically contact an exposed shielding layer of a cable terminated to the corresponding pair of signal pads.

[0126] 3. The switching card according to configuration 1, further comprising:

[0127] a second surface opposite the first surface, the second surface comprising a second plurality of pads at least partially disposed on the second surface; and

[0128] At least one second conductive structure is electrically and mechanically connected to the second plurality of pads.

[0129] 4. The switching card according to configuration 1, wherein:

[0130] The switch card includes a plurality of mating contact portions adjacent to a first edge, and the mating contact portions are narrow and long in a first direction orthogonal to the first edge;

[0131] The at least one conductive structure extends on the surface in a second direction orthogonal to the first direction of the switch card such that the at least one conductive structure is dimensioned to electrically connect to shielding layers of a plurality of cables; and

[0132] Each of the plurality of shielding layers is associated with a cable of the plurality of cables arranged in parallel along the first direction and disposed side by side along the second direction.

[0133] 5. The switching card according to configuration 1, wherein:

[0134] The switch card further includes a plurality of openings in the surface; and

[0135] The at least one conductive structure also includes a plurality of protrusions extending into corresponding openings of the plurality of openings.

[0136] 6. The switching card according to configuration 1, wherein:

[0137] The switch card includes a plurality of contact pads adjacent to a first edge, and the pads are narrow and long in a first direction orthogonal to the first edge;

[0138] The plurality of tabs of the at least one conductive structure includes a first set of tabs and a second set of tabs;

[0139] The first set of tabs are in a first row, the first row extending in a second direction parallel to the first edge of the paddle card; and

[0140] The second set of lugs is oriented along a second row, wherein the second row extends along the first direction and the second row is spaced apart from the first row along the second direction.

[0141] 7. The switching card of configuration 6, wherein the at least one conductive structure further comprises a plurality of openings, wherein each of the plurality of openings extends along the surface in the first direction and the second direction.

[0142] 8. The switching card according to configuration 7, wherein:

[0143] The plurality of openings are oriented along a third row extending along the second direction; and

[0144] The third row is between the first row and the second row in the first direction.

[0145] 9. The switching card of configuration 7, wherein each of the plurality of openings surrounds a pad of a second group of pads at least partially disposed on the surface such that the at least one conductive structure is not in mechanical contact with the second group of pads.

[0146] 10. The switching card according to configuration 7, wherein:

[0147] The plurality of pads are arranged in a first row and a second row spaced apart from the first row along the first direction, wherein:

[0148] The first row and the second row extend along the second direction;

[0149] The first row and the second row are in a second region, the second region being adjacent to a second edge opposite the first edge; and

[0150] The first row and the second row include a plurality of groups of pads, the plurality of groups of pads including a pair of signal pads and an associated ground pad adjacent to the signal pads; and

[0151] The conductive structure is electrically and physically connected to the ground pads in the first row of pads and the second row of pads, and each of the plurality of openings is formed to surround a pair of signal pads in the first row of pads and the second row of pads on at least three sides.

[0152] 11. The switch card of configuration 10, wherein the plurality of openings comprises:

[0153] a first plurality of openings arranged along a third row extending along the second direction, wherein the third row is between the first row and the second row; and

[0154] A second plurality of openings is arranged along a fourth row extending along the second direction, wherein the fourth row is adjacent to the second row.

[0155] 12. The switch card of configuration 6, wherein the at least one conductive structure further comprises a set of fingers extending in the second direction along the surface.

[0156] 13. The switching card according to configuration 6, wherein:

[0157] The plurality of openings are arranged along a third row extending along the first direction;

[0158] the third row is spaced apart from the first row and the second row in the second direction; and

[0159] The third row is positioned closer to the first edge of the switch card than the first row and the second row.

[0160] 14. The paddle card of configuration 1, wherein the at least one conductive structure comprises a plurality of conductive structures, each conductive structure of the plurality of conductive structures being electrically and mechanically connected to pads of an associated subset of the plurality of pads.

[0161] 15. The switching card of configuration 14, wherein:

[0162] The switch card includes a plurality of contact pads adjacent to a first edge, and the pads are narrow and long in a first direction orthogonal to the first edge;

[0163] Each of the plurality of conductive structures includes a tab of the plurality of tabs in a first row, wherein the first row extends in a second direction orthogonal to the first direction.

[0164] 16. The paddle card of configuration 15, wherein the plurality of tabs of the plurality of conductive structures comprises one or more U-shaped tabs.

[0165] 17. The switch card of configuration 15, wherein the plurality of conductive structures include one or more tabs at interior portions of the conductive structures.

[0166] 18. The switch card of configuration 15, wherein the plurality of conductive structures are arranged along the first row.

[0167] 19. The switch card of configuration 15, further comprising a second plurality of pads, wherein:

[0168] the second plurality of pads are oriented along a second row, wherein the second row extends along the first direction;

[0169] The second row is spaced apart from the first row along a mating direction of the switch cards.

[0170] 20. The switching card according to configuration 1, wherein:

[0171] The switch card includes a length extending along a first direction;

[0172] The switch card includes a first end, the first end including a first width extending along a second direction orthogonal to the first direction; and

[0173] The switch card includes a second end opposite the first end, the second end including a second width extending along the second direction;

[0174] The first width, the second width, or the first width and the second width are between 13.25 mm and 19.75 mm.

[0175] 21. A cable assembly, comprising:

[0176] a switch card comprising a surface, wherein the switch card comprises a first plurality of pads and a second plurality of pads on the surface;

[0177] a plurality of cables, wherein each cable of the plurality of cables comprises at least one conductor and a shielding foil, wherein a conductor of the at least one conductor is electrically and mechanically connected to a pad of the first plurality of pads;

[0178] at least one conductive structure electrically and physically connected to a pad of the second plurality of pads, wherein:

[0179] The at least one conductive structure includes a plurality of tabs; and

[0180] Each tab of the plurality of tabs at least partially wraps around a cable of the plurality of cables and is electrically connected to the shielding foil of the cable.

[0181] 22. The cable assembly according to configuration 21, wherein:

[0182] The first plurality of pads and the second plurality of pads include pairs of adjacent signal pads and ground pads disposed between adjacent pairs of signal pads;

[0183] Each cable of the plurality of cables comprises two conductors, wherein the two conductors of each cable are mounted to a corresponding pair of adjacent signal pads;

[0184] The at least one conductive structure comprises a plurality of parts, each part:

[0185] electrically and physically connected to a ground pad in the set of pads adjacent to a corresponding pair of signal pads in the set of pads; and

[0186] A lug of the plurality of lugs is included that is aligned with the corresponding pair of signal pads to electrically contact an exposed shielding layer of a cable terminated to the corresponding pair of signal pads.

[0187] 23. The cable assembly of configuration 21, wherein:

[0188] The end portion of the cable includes an exposed portion of the shielding foil; and

[0189] The shielding foil at least partially surrounds the at least one conductor.

[0190] 24. The cable assembly of configuration 21, wherein each cable of the plurality of cables is a two-wire cable without a drain wire.

[0191] 25. The cable assembly of configuration 21, wherein:

[0192] The switch card includes a length extending along a first direction;

[0193] The first plurality of pads and the second plurality of pads are arranged in a first row and a second row, wherein the first row and the second row extend along a second direction orthogonal to the first direction, and the first row is spaced apart from the second row in the first direction;

[0194] The cables of the plurality of cables are arranged in parallel along the first direction and arranged side by side along the second direction; and

[0195] The plurality of cables are electrically and physically connected in an alternating manner such that conductors of adjacent ones of the plurality of cables are electrically and mechanically connected to pads of the first plurality of pads in different ones of the first and second rows.

[0196] 26. The cable assembly of configuration 25, wherein:

[0197] A cable of the plurality of cables having conductors electrically and mechanically connected to a pad of the first plurality of pads in the first row is configured to pass a signal in a first direction; and

[0198] Cables of the plurality of cables having conductors electrically and mechanically connected to pads of the first plurality of pads in the second row are configured to transmit signals in a second direction different from the first direction.

[0199] 27. The cable assembly of configuration 21, wherein:

[0200] The switch card includes a length extending along a first direction;

[0201] The paddle card includes a width extending along a second direction orthogonal to the first direction, wherein the width is between 13.25 millimeters and 19.75 millimeters.

[0202] 28. The cable assembly of configuration 27, wherein:

[0203] The plurality of cables includes eight two-wire cables; and

[0204] The at least one conductor in each cable of the plurality of cables comprises a gauge between 34 American Wire Gauge (AWG) and 25 AWG.

[0205] 29. The cable assembly of configuration 21, wherein:

[0206] The switch card includes a length extending along a first direction;

[0207] The paddle card includes a width extending along a second direction orthogonal to the first direction, wherein the width is between 22 millimeters and 27 millimeters.

[0208] 30. The cable assembly of configuration 29, wherein:

[0209] The plurality of cables includes eight two-wire cables; and

[0210] The at least one conductor in each cable of the plurality of cables comprises a gauge between 34 American Wire Gauge (AWG) and 25 AWG.

[0211] 31. The cable assembly of configuration 21, wherein electrical connection of the plurality of tabs of the at least one conductive structure to the shielding foil of each cable suppresses crosstalk between cables in the plurality of cables.

[0212] 32. The cable assembly of configuration 31, wherein far-end crosstalk of the plurality of cables is less than 35 dB in a frequency range of 1 GHz to 20 GHz.

[0213] 33. The cable assembly of configuration 31, wherein far-end crosstalk of the plurality of cables is less than 40 dB substantially in a frequency range of 1 GHz to 20 GHz.

[0214] 34. The cable assembly of configuration 21, wherein the plurality of cables comprises:

[0215] Length between 2.5m and 3.5m;

[0216] 100 ohm impedance; and

[0217] Less than 17dB end-to-end attenuation.

Claims

1. A switching card, comprising: a surface comprising a plurality of pads on the surface; as well as at least one conductive structure electrically and physically connected to a pad of the plurality of pads, wherein: The at least one conductive structure includes a plurality of tabs, each tab extending upwardly from the surface; and Each lug of the plurality of lugs is configured to make electrical contact with an exposed shielding layer of an associated cable.

2. The switching card according to claim 1, wherein: The plurality of pads include pairs of signal pads and ground pads disposed between adjacent pairs of signal pads; and The at least one conductive structure comprises a plurality of parts, each part: electrically and physically connected to a ground pad of the plurality of pads adjacent to a corresponding pair of signal pads of the plurality of pads; and A lug of the plurality of lugs is included that is aligned with the corresponding pair of signal pads to electrically contact an exposed shielding layer of a cable terminated to the corresponding pair of signal pads.

3. The switching card according to claim 1, further comprising: a second surface opposite the first surface, the second surface comprising a second plurality of pads at least partially disposed on the second surface; as well as At least one second conductive structure is electrically and mechanically connected to the second plurality of pads.

4. The switching card according to claim 1, wherein: The switch card includes a plurality of mating contact portions adjacent to a first edge, and the mating contact portions are narrow and long in a first direction orthogonal to the first edge; the at least one conductive structure extending on the surface in a second direction orthogonal to the first direction of the switch card such that the at least one conductive structure is dimensioned to be electrically connected to shielding layers of a plurality of cables; and Each of the plurality of shielding layers is associated with a cable of the plurality of cables arranged in parallel along the first direction and disposed side by side along the second direction.

5. The switch card according to claim 1, wherein: The switch card further includes a plurality of openings in the surface; and The at least one conductive structure also includes a plurality of protrusions extending into corresponding openings of the plurality of openings.

6. The switching card according to claim 1, wherein: The switch card includes a plurality of contact pads adjacent to a first edge, and the pads are narrow and long in a first direction orthogonal to the first edge; The plurality of tabs of the at least one conductive structure includes a first set of tabs and a second set of tabs; The first set of tabs are in a first row, the first row extending in a second direction parallel to the first edge of the paddle card; and The second set of lugs is oriented along a second row, wherein the second row extends along the first direction and the second row is spaced apart from the first row along the second direction.

7. The switching card according to claim 6, wherein: The at least one conductive structure further includes a plurality of openings, wherein each opening of the plurality of openings extends along the surface in the first direction and the second direction.

8. The switching card according to claim 7, wherein: The plurality of openings are oriented along a third row extending along the second direction; and The third row is between the first row and the second row in the first direction.

9. The switching card according to claim 7, wherein: Each opening of the plurality of openings surrounds a pad of a second group of pads at least partially disposed on the surface such that the at least one conductive structure is not in mechanical contact with the second group of pads.

10. The switch card according to claim 7, wherein: The plurality of pads are arranged in a first row and a second row spaced apart from the first row along the first direction, wherein: The first row and the second row extend along the second direction; The first row and the second row are in a second region, the second region being adjacent to a second edge opposite the first edge; and The first row and the second row include a plurality of groups of pads, the plurality of groups of pads including a pair of signal pads and an associated ground pad adjacent to the signal pads; and The conductive structure is electrically and physically connected to the ground pads in the first row of pads and the second row of pads, and each of the plurality of openings is formed to surround a pair of signal pads in the first row of pads and the second row of pads on at least three sides.

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