Patent Abstract:
A plug module is provided that includes a first mating end and a second mating end. The first mating end is configured to mate with a predefined port, such as a QSFP port. The second mating end can support two or more micro receptacles that allow the plug module to provide an octopus-like cable assembly without requiring the predetermination of a particular length of cable.

Full Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 62/108,276, filed Jan. 27, 2015, which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to the field of input/output (IO) connectors, more specifically to IO connectors suitable for use in high data rate applications. 
       DESCRIPTION OF RELATED ART 
       [0003]    Input/output (IO) connectors that have four communication channels (e.g., 4 transmits and 4 receives) are known. One example is the quad small form-factor pluggable (QSFP) connector. These types of connectors are suited to support high bandwidth applications due to the inclusion of the four communication channels. 
         [0004]    One issue that sometimes comes up with a connector such as the QSFP style connector is that there is a desire to have a large amount of bandwidth available on a switch that is positioned as a Top of Rack (ToR) switch but the bandwidth available in one QSFP port provided in such a ToR switch might be greater than another single port really needs. The desire to break out the channel sometimes existed in standard QSFP products that provided 40 Gbps and this desired is expected to become a more prevalent issue in products designed to support 100 Gbps, such as 100 Gbps capable QSFP products. 
         [0005]    One existing way to address this issue is to have what is sometime referred to as a break-out cable or octopus cable. For example, a cable assembly could have a QSFP plug module on one end and have four cables extending from the QSFP plug to four separate small form-factor pluggable (SFP) style plug modules. This allows a single QSFP port to communicate with 4 SFP ports and, for high performing assemblies, each communication channel can support 25 Gbps of bidirectional communication. While this is an effective way to break out the four communication channels so as to allow one port to communicate with four other ports, the use of octopus cables is generally disfavored. One issue is that a cable from a ToR switch will have to reach lengths of less than a foot to more than a meter. As can be appreciated, it is difficult to know in advance how far each cable of an octopus cable assembly is going to need to reach. Therefore it is common to select a length that is long enough for all cases but is too long for most cases. This tends to result in a mess of cables that is difficult to understand or work with once installed. Consequentially, certain individuals would appreciate further improvements in connector configurations. 
       SUMMARY 
       [0006]    A plug module is disclosed that includes a first mating end that is configured to mate with a predefined port (such as a conventional connector receptacle) and has a second mating end that includes a plurality of micro receptacles. A paddle card can be positioned at the first mating end and the micro receptacles can be supported so that they are offset upward, compared to the paddle card. A plurality of cable assemblies with micro plugs can be connected to the plurality of micro receptacles such that each cable assembly can offer a different length and have a desired far end termination configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present invention is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which: 
           [0008]      FIG. 1  illustrates a perspective view of an embodiment of a break out connector module. 
           [0009]      FIG. 2  illustrates a simplified perspective view of the embodiment depicted in  FIG. 1 . 
           [0010]      FIG. 3  illustrates a perspective, partially exploded view of the embodiment depicted in  FIG. 2 . 
           [0011]      FIG. 4  illustrates an exploded perspective view of the embodiment depicted in  FIG. 2 . 
           [0012]      FIG. 5  illustrates a perspective simplified view of the embodiment depicted in  FIG. 4 . 
           [0013]      FIG. 6  illustrates a perspective enlarged view of the embodiment depicted in  FIG. 5 . 
           [0014]      FIG. 7  illustrates a perspective simplified view of the embodiment depicted in  FIG. 6 . 
           [0015]      FIG. 8  illustrates a perspective view of the embodiment depicted in  FIG. 7 . 
           [0016]      FIG. 9  illustrates a perspective view of the embodiment depicted in  FIG. 8  but with a latch in a second position. 
           [0017]      FIG. 10  illustrates a perspective view of an embodiment of a break out module with the latch system removed. 
           [0018]      FIG. 11  illustrates a perspective view of an embodiment of a circuit board supporting four connectors. 
           [0019]      FIG. 12  illustrates a perspective simplified view of the embodiment depicted in  FIG. 11  with just one connector housing positioned on the circuit board. 
           [0020]      FIG. 13  illustrates another perspective view of the embodiment depicted in  FIG. 12 . 
           [0021]      FIG. 14  illustrates a perspective view of an embodiment of a first housing wafer. 
           [0022]      FIG. 15  illustrates another perspective view of the embodiment depicted in  FIG. 14 . 
           [0023]      FIG. 16  illustrates a perspective view of an embodiment of a second housing wafer. 
           [0024]      FIG. 17  illustrates another perspective view of the embodiment depicted in  FIG. 16 . 
           [0025]      FIG. 18  illustrates a perspective, partially exploded view of an embodiment of a first housing wafer. 
           [0026]      FIG. 19  illustrates another perspective view of the embodiment depicted in  FIG. 18 . 
           [0027]      FIG. 20  illustrates another perspective view of the embodiment depicted in  FIG. 18 . 
           [0028]      FIG. 21  illustrates an elevated rear view of a portion of an embodiment of a terminal set, showing an embodiment of uniform construction of the terminals. 
           [0029]      FIG. 22  illustrates a perspective simplified view of an embodiment of a first housing wafer with a terminal block removed. 
           [0030]      FIG. 23  illustrates a schematic representation of an embodiment of a cable assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    The detailed description that follows describes exemplary embodiments and is not intended to be limited to the expressly disclosed combination(s), Therefore, unless otherwise noted, features disclosed herein may be combined together to form additional combinations that were not otherwise shown for purposes of brevity. 
         [0032]    As can be appreciated from the Figures, a plug module  10  is depicted and as depicted can result in a quad small-form factor pluggable (QSFP) module. Thus, the depicted embodiment allows for the insertion of the plug module  10  into an existing QSFP receptacle port and can provide four break out connectors. QSFP modules are fairly beneficial for Top of Rack (ToR) applications as well as many other applications that benefit from 4 channels of high-speed data. The features discussed herein, however, are not limited to use with QSFP style connectors as other sized plug receptacle could also provide similar functionality (with larger plug modules potentially supporting additional connectors). 
         [0033]    The depicted plug module  10  includes a latch  30  with an optional pull-tab  32  that is removed in  FIG. 2 . As can be appreciated, the plug module has a body  40  formed of a lower half  43   a  and an upper half  43   b  that are secured together with fasteners  44  and the plug module  10  has a first mating end  11  and a second mating end  12  opposing the first mating end  11 . In operation, the first mating end  11  is configured to mate with a receptacle (not shown but which could be a standard QSFP receptacle) and the second mating end  12  is intended to provide receptacles as discussed herein. 
         [0034]    A paddle card  45  with contact pads  46  is provided on a first mating end  11  and the paddle card  45  is configured to mate with a corresponding connector (typically one that includes a card slot). Four micro receptacles  60  are provided at the second mating end  12  and each micro receptacle  60  includes a mating face  61   a  and a rear face  61   b.  While such data rates are not required, the micro receptacles  60  mounted in the plug module  10  can each support a two-way 25 Gbps channel with a design that provides one transmit pair and one receive pair (both configured to operate at 25 Gbps using NRZ encoding) with a total of 16 pins while being less than 7 mm wide. It should be noted that the depicted plug module  10  is configured as a QSFP style plug module and thus is intended to mate with a receptacle that supports four two-way channels (e.g., with a 4× receptacle) and thus it makes sense to break out the one 4× into four 1× connectors. Do to size constraints, the micro receptacles  60  have less pins than a typical SFP connector would have but for many applications the 16 pins are sufficient. It should be noted that if the plug module was configured to engage a 2× receptacle then two 1× connectors would be sufficient from a break out standpoint and the design of the plug module could be so modified. 
         [0035]    Each micro receptacle  60  is supported on a micro board  52  and includes a cage  62  and a latch  63 . The latch  63  ensures that a mating micro plug connector  90  is securely fastened to the micro receptacle  60  and is not going to fall out do to vibration and inadvertent application of force to the micro plug connector  90 . It should be noted that the depicted design includes a cable  47  (shown in truncated manner) that connects the paddle card  45  to the micro board  52 . For purposes of illustration the termination of the cable  47  to the micro board  52  is omitted as such a termination is known and can be substantially the same as the termination shown on the paddle card  45 . As is discussed, such a configuration is not required but it has been determination that such a configuration is desirable because it allows the micro board  52  to be offset upward compared to the paddle card  45 . It turns out that offsetting the micro receptacles upward compared to the paddle card  45  is beneficial for users and it can help make it easier to package the plug module in a given system. Alternative embodiments could use flex circuitry to connect the micro receptacles  60  to the paddle card  45  and still provide the offset configuration. Other alternative embodiments that provide the optional offset configuration could include the use of a non-planar circuit board but in general a circuit board tends to be more lossy than a cable so care is needed to ensure the selected configuration is compatible with the signaling frequency and loss budget. 
         [0036]    The micro receptacles  60  provide a micro port  65  that is defined by the cage  62  (preferably formed of a metal) that extends around a tongue  73  of a housing  70  that is formed of an insulative material. The housing  70  supports the terminals  80 . In an embodiment the housing can be formed of a first wafer housing  71   a  and a second wafer housing  71   b,  where the first and second water housings  71   a,    71   b  are each insert molded around a row of terminals such that corresponding contacts  80   a  are supported on a first tongue half  73   a  and a second tongue half  73   b.    
         [0037]    As can be appreciated, the micro receptacles  60  are configured as right-angle SMT style connectors with terminal sets  68  that each provide a row of terminals and are intended to be mounted on a pad array  54  on the micro board  52 . In an embodiment the terminal sets  68  can have terminals  80  on a 0.5 mm pitch. Each of the terminals  80  includes a contact  80   a , a tail  80   b  and a body  80   c  that extend therebetween. As can be appreciated, the tails  80   b  can be provided in two rows. Naturally, the mating micro plug connector  90  has mating terminals that are also arranged at a 0.5 mm pitch. In spite of the small size, the far end crosstalk can be more than 35 dB down and preferably can be more than 40 dB down out to 12.5 GHz signaling frequency. 
         [0038]    To help provide the desirable performance, one of the rows of terminals can include signal terminals  86  (that form differential signal pairs  89   a,    89   b ) spaced apart by a ground terminal  85  and in an embodiment the tongue and contact configuration can be adjusted so that the ground terminals  85  extends past the signal terminals  86  and notches  74   a ,  74   b  are provided in the first and second tongue halves  73   a,    73   b  where the corresponding notch is placed at the end of the signal terminals  86  that form the differential pair. While such an optional configuration is not required, it has been determined that for a compact design as depicted it is beneficial to have the notches  74   a,    74   b  as depicted so as to improve the tuning of the terminals. The notches  74   a,    74   b , in combination with tuning apertures  77 , can be arranged so that the signal terminals are preferentially coupled (e.g., more signal energy travels on the signal terminals than would normally travel on a symmetric configuration). This can be done by modifying the dielectric constant of the structure surrounding the signal terminals so that they are more tightly coupled together than one of the signal terminals is coupled to an adjacent ground terminal. As can be appreciated from  FIG. 21 , however, in an embodiment the spacing and construction of the terminals can be symmetric in that the space between ground and signal terminals, along with the shape of the terminals, is substantially the same along the body and tail sections. 
         [0039]    As depicted, the first wafer half  71   a  includes a terminal block  82  that attaches to a projection  81  via a receiving channel  84 . The terminal block  82 , while it can be integrated into the first wafer half  71   a,  is preferably separate and provides a terminal comb  83  that helps control the location and spacing of the tails. The second wafer half  71   b  can be an integral unit, as is depicted. 
         [0040]    One issue that exists is the inclusion of the latch  63 . As can be appreciated, there is very little space available and a latch that could be operated without a tool would be difficult to package. For certain applications a latch may not be required. However, for server applications and any applications where there is a need for a robust configuration that is resistant to accidental disengagement of a connector, a latch is needed. While it is common to place the latch on the plug module, the micro plug modules are so small and the space is so tight when they are arranged as depicted that providing a latch on the micro plugs is not feasible. As a result, Applicants have determined that the latch  63  can be provided on the micro receptacle  60 . 
         [0041]    The depicted system therefore includes an optional latch  63  that is configured to retain a micro plug module that is inserted into the micro receptacle. The latch  63  includes a securing arm  63   a  that has one end secured to the cage  62  of the micro receptacle  60  and has retaining fingers  63   b  that extend through retaining apertures  64  in the cage  62  so that the retaining fingers  63   b  can engage the inserted plug connector and a release flange  63   c  is moveable with the use of a tool. In operation a tool can be inserted under the release flange  63   c  so as to cause the securing arm  63   a  to be translated upward. This will cause retaining fingers  63   b  on the securing arm  63   a  to disengage from retaining holes in the micro plug and the micro plug can then be removed. The translation of the securing arm  63   a  can be appreciated from the embodiments depicted in  FIGS. 8 and 9 . Naturally, if it is desirable to remove several micro plugs from a plug module  10  then it may be easier to first disconnect the plug module first and then remove the micro plugs. 
         [0042]    As noted above, the micro receptacles  60  are mounted on a micro board  52 . As depicted, the micro board  52  is separate from the paddle card  45 . In an alternative embodiment the paddle card could be extended so that the micro board  52  and the paddle card  45  were integral or a single board and the micro receptacles  60  could be mounted directly on the paddle card  45  (and thus communicate via traces provided on the paddle card  45 ). Otherwise the micro board  52  and the paddle card  45  can be connected together in any desirable manner. It should be noted that if desired the plug module could also include circuitry such as a retimer and/or an amplifier to allow for improved operation. 
         [0043]    While active components can be added, it should be noted that the depicted configuration is intended to work as a passive system in certain applications. This is beneficial because the micro plug modules can be mounted on a cable assembly that has a different style connector on the opposite end. Thus the micro plug connector  90  could be provided on one end of a cable  92  and a conventional SFP style plug  94  could be placed on the other end (such as is depicted schematically in  FIG. 23 ). 
         [0044]    The disclosure provided herein describes features in terms of preferred and exemplary embodiments thereof Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.

Technology Classification (CPC): 7