Modular plug connector with multilayer PCB for very high speed applications

Abstract

A modular RJ45-type plug apparatus is provided for forming a connector interface with a connector jack in a high speed data transmission network. A housing comprises an insulative front portion and a conductive shield portion attachable to define an interior, within which is positioned a contact subassembly including a first PCB having cable mounting pads on one end and through holes for elongate plug contacts on the other end. The contacts are connected on one end to the first PCB and on a second end to a second PCB, with bridge portions therebetween collectively defining a jack contact interface. The second PCB comprises desired electrical characteristics which provide the apparatus with certain capacitance compensation properties, wherein the capacitance compensation is offset from a signal path defined between the jack-plug connector interface and the cable pairs.

Claims

1. A modular connector plug apparatus for forming a connector interface with a connector jack in a high speed data transmission network, comprising a housing and a contact subassembly configured for positioning within the interior of said housing and further comprising a first printed circuit hoard (PCB) having a first end and a second end, the second end comprising conductive mounting pads for each of a plurality of cable pairs, the apparatus further characterized in that: the housing comprises an insulative front portion and a conductive shield portion attachable to define the interior, and the contact subassembly comprises a plurality of elongate plug contacts each comprising a first end mounted on the first end of the first PCB, a second end distal from the first end, and a bridge portion there between, the bridge portions of the plurality of plug contacts collectively defining an interface for corresponding contacts of a connector jack, and the respective second ends of the plurality of plug contacts mounted on a second PCB, wherein the second PCB comprises desired electrical characteristics which provide the apparatus with certain capacitance compensation properties, and wherein the capacitance compensation is offset from a signal path defined between the jack-plug connector interface and the cable pairs.

2. The apparatus of claim 1, wherein the first PCB further comprises: through holes for receiving the respective first ends of the plug contacts; and an air gap slotted from the second end and extending ire parallel with electrical traces between the through-holes and the mounting pads.

3. The apparatus of claim 2, comprising a substantially planar conductive shield located within the slotted air gap and commoned to one or more ground planes within the first PCB, in an orthogonal orientation with respect to a surface plane of the first PCB.

4. The apparatus of claim 3, wherein first and second pairs of conductive mounting pads are provided on a first surface of the first PCB, and respectively positioned on opposing first and second sides of the planar conductive shield, and third and fourth pairs of conductive mounting pads are provided on an opposing second surface of the first PCB, and respectively positioned on the opposing first and second sides of the planar conductive shield.

5. The apparatus of claim 4, wherein the bridge portion for each plug contact has a maximum width extending in a direction perpendicular to a PCB length, at least one plug contact having a maximum width greater than the maximum width of another plug contact, wherein each plug contact defines an electrode of a further compensating capacitance formed between adjacent pairs of plug contacts, each further compensating capacitance defined at, least partially by a distance between the respective adjacent pair of plug contacts at the contact interface.

6. The apparatus of claim 5, wherein the respective bridge portion for each plug contact has a length extending between the first end and the second end, at least one plug contact having a bridge portion length shorter than the bridge portion length of another plug contact.

7. The apparatus of claim 6, wherein the respective first ends for a first plurality of plug contacts and a second plurality of plug contacts are situated in first and second parallel spaced planes.

8. The apparatus of claim 1, wherein the contact subassembly comprises a contact retainer configured to receive the plurality of contacts and composed of an isolative material having characteristic dielectric properties providing a supplemental capacitance compensation between adjacent contact pairs and offset from the signal path.

9. The apparatus of claim 8, wherein the contact retainer comprises first and second opposing side portions with protrusions extending therefrom, and wherein the front portion of the housing comprises corresponding first and second interior slots configured to slidably receive the first and second opposing side portions via the protrusions.

10. The apparatus of claim 9, wherein the first and second interior slots comprise notches along their respective lengths, and the protrusions are configured to compress during insertion into the front portion of the housing and then extend outward to engage the notches.

11. The apparatus of claim 10, wherein the front portion of the housing comprises a top side having one or more apertures, and the conductive shield portion of the housing comprises a respective one or more latches configured to engage the one or more apertures when the front portion and the conductive shield portion are slidably engaged.

12. The apparatus of claim 11, wherein the conductive shield portion comprises jack grounding tabs extending along first and second opposing outer side walls of the front portion of the housing when the front portion and the conductive shield portion are slidably engaged.

13. The apparatus of claim 12, wherein the first and second jack grounding tabs further respectively comprise shield retention tabs configured to fold over the notches of the first and second interior slots when the front portion and the conductive shield portion are slidably engaged, further to engage the protrusions of the contact retainer as extended outward and retained therein.

14. The apparatus of claim 13, wherein the bridge portion for each plug contact has a maximum width extending in a direction perpendicular to a PCB length, at least one plug contact having a maximum width greater than the maximum of another plug contact, wherein each plug contact defines an electrode of a further compensating capacitance formed between adjacent pairs of plug contacts, each further compensating capacitance defined at least partially by a distance between the respective adjacent pair of plug contacts at the contact interface.

15. The apparatus of claim 14, wherein the respective bridge portion for each plug contact has a length extending between the first end and the second end, at least, one plug contact having a bridge portion length shorter than the bridge portion length of another plug contact.

16. The apparatus of claim 15, wherein the respective first ends for a first plurality of plug contacts and a second plurality of plug contacts are situated in first and second parallel spaced planes.

17. The apparatus of claim 1, wherein the second PCB comprises a plurality of substrate layers having parallel plates disposed therein, and a value of the capacitance compensation is defined by an area, distance and dielectric constant associated therewith.

18. The apparatus of claim 1, wherein the contact subassembly is configured to withstand 1000 VDC between any two adjacent contacts, and 1500 VDC between any two non-adjacent contacts and/or between any one contact and the conductive shield, without shorting or flash-over.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a perspective view representing a first embodiment of a modular connector plug as disclosed herein for high speed data transmission.

(2) FIG. 2 is an inverted perspective view of the embodiment illustrated in FIG. 1.

(3) FIG. 3 is an exploded perspective view of the embodiment illustrated in FIG. 1.

(4) FIG. 4 is a first further exploded perspective view of the embodiment illustrated in FIG. 1.

(5) FIG. 5 is a second further exploded perspective view of the embodiment illustrated in FIG. 1.

(6) FIG. 6 is a third further exploded perspective view of the embodiment illustrated in FIG. 1.

(7) FIG. 7 is a perspective view representing an exemplary contact retainer with contacts, from the modular connector plug of FIG. 1.

(8) FIG. 8 is an exploded perspective view representing the contacts removed from the contact retainer of FIG. 7.

(9) FIG. 9 is a perspective view representing a front plug housing for the modular connector plug of FIG. 1.

(10) FIG. 10 is a perspective view representing a plug subassembly for the modular connector plug of FIG. 1, terminated to a shielded twisted pair cable as disclosed herein.

(11) FIG. 11 is a top view representing an exemplary primary printed circuit board (PCB) for the embodiment of a modular plug as illustrated in FIG. 1.

(12) FIG. 12 is a top view representing exemplary top copper layer for the primary PCB of FIG. 11.

(13) FIG. 13 is a top view representing an exemplary ground plane for the primary PCB of FIG. 11.

(14) FIG. 14 is a top view representing an exemplary bottom copper layer for the primary PCB of FIG. 11.

(15) FIG. 15 is a top view representing an exemplary compensation PCB for the embodiment of a modular plug as illustrated in FIG. 1.

(16) FIG. 16 is a top view representing an exemplary top copper layer for the compensation PCB of FIG. 15, including NEXT and RL compensation capacitance plates.

(17) FIG. 17 is a top view representing exemplary bottom copper layer for the compensation PCB of FIG. 15, including NEXT and RL compensation capacitance plates.

DETAILED DESCRIPTION

(18) Referring generally to FIGS. 1-17, various exemplary embodiments of a modular connector plug may now be described in detail. Where the various figures may describe embodiments sharing various common elements and features with other embodiments, similar elements and features are given the same reference numerals and redundant description thereof may be omitted below.

(19) An initial embodiment of a modular connector plug as represented in FIGS. 1 and 2 may be configured to form a connector interface with a corresponding female connector jack (not shown) including a plurality of female jack contacts in a high speed data transmission network. A housing is formed of an insulating (e.g., plastic) plug body 107 in operative attachment with a conductive (e.g., metal) shield 106 and an insulating (e.g., plastic) strain relieving body 105. The plug is applied to shielded twisted pair cable 104. Within the plug body is a plug sub-assembly 108. When the plug is to be terminated in the field, it may be supplied in an unassembled configuration (see, e.g., as represented in FIG. 3).

(20) FIG. 4 shows the strain relief 105 and the outer shield 106 in greater detail. Integral to the strain relief 105 are a cable flexing portion 105a, a tab anti-snag portion 105b and a plurality of latch features 105c that engage with shield apertures (e.g., cut-outs) 106e thus locating and retaining the outer shield 106.

(21) The outer shield 106 may also be constructed with additional integral features. In an exemplary embodiment, shield retention tabs 106a are formed over once the shield 106 and strain relief 105 are assembled to the plug sub assembly 108 and plug body 107. These retention tabs 106a assist in holding the plug together. The electrical ground path of the plug connector is maintained by the cable ground springs 106b and the jack ground tabs 106c. The cable ground springs 106b are formed inward from the main shield 106 and make contact with the foil shields 170a of the twisted pairs 170. The ground path continues through the shield 106 and then continues through the plug ground tabs 106c. These plug ground tabs 106c are disposed on either side of the plug body 107 and make contact with ground springs that are present in typical jack connectors. Plug housing latches 106f engage with cut-outs 107d in the front housing 107.

(22) FIGS. 5 and 6 show an exemplary embodiment of the plug sub-assembly 108. These two figures are shown in the assembled (FIG. 5) and unassembled or exploded (FIG. 6) configurations. The crimp ferrule 160 is shown in an uncrimped state 160a and in a crimped state 160b. Exemplary assembly and functionality of this plug subassembly 108 may be further detailed hereinafter.

(23) FIG. 7 shows the contacts 130 inserted into a contact retainer 140 and placed onto a primary printed circuit board (PCB) 110. The contacts are held in place by the interference between slots 140b in the contact retainer 140 and an integral barb portion 130a of the contacts 130. PCB 110 is a multilayer circuit board that provides electrical signal and ground connection paths between the shielded twisted pair cable 104 and the plug signal contacts 130 and ground contacts 106c. The plug contacts 130 are electrically connected to PCB 110 by means of plated-through-holes 110b, and as further noted below, the cable pairs 170 are electrically connected to conductive pads 110a. The electrical paths between the plug contacts 130 and the cable pairs 170 are controlled by matched impedance conductive traces. Also controlled are the inductance and electrical length of the electrical pathways.

(24) In the embodiment shown, each plug contact 130 includes a first end connected to the PCB 110 via a respective through-hole 110b. The first ends of each respective plug contact 130 extend in transverse orientation with respect to a length of the PCB 110. The first d of each plug contact 130 may in an embodiment also be at least coincident with a lower plane of the PCB 110. Each plug contact 130 further includes a second end which extends in parallel with the other respective second ends of the other plug contacts and in transverse orientation with respect to the length of the PCB 110. In the configuration shown, when the first end of each plug contact 130 is connected to the PCB 110 at a respective contact hole 110b, the second end of each plug contact overhangs the end of the PCB. Each plug contact 130 further includes what may be referred to herein as a bridge portion between the respective first end and second end. The resulting shape of each plug contact 130 may resemble a staple as shown in FIG. 8, having, for example, rounded engagement portions between the bridge and the respective ends.

(25) The plug contact configurations are not necessarily so limited, however, and in alternative embodiments within the scope of the present disclosure it may be understood that the engagement portions may be squared, beveled, or the like.

(26) In the embodiment shown some of the contacts, namely 130-3 and 130-5 (see contact detail in FIG. 8) are partially wider (see, e.g., 130d) than other contacts. All contacts are aligned linearly in the connector front facing the jack, but the odd-numbered contacts 130-1, 130-3, 130-5 and 130-7 are in general shorter the even-numbered contacts 130-2, 130-4, 130-6, 130-8. The contact through-holes 110b may accordingly form two rows including a row of first contact through-holes and a row of second contact through-holes, wherein the first contact through-holes are closer to the front end of the PCB 110 as facing the jack.

(27) A high capacitive coupling is selectively created, e.g., between contact pair 130-3 and 130-4 and also contact pair 130-5 and 130-6. These contact pairs are located in the contact retainer 140 which is composed of an isolative material. The characteristic dielectric properties of this isolative material are known and controlled, thus producing a controlled capacitance between the contact pairs. Because this capacitance is intimately located at the point of contact between the plug and jack contacts, there is little to no signal delay (and phase shift) resulting in very effective capacitive compensation.

(28) Additional capacitive compensation is provided by the secondary PCB 120 (see FIG. 3). The capacitance values developed by the secondary PCB 120 are generated by controlling the area and separation distance between parallel plates 120b constructed within the layers of the secondary PCB. Controlling the area, distance and dielectric constant of the insulative PCB material will control the capacitance values in the compensation zones 120c. Referring for illustrative purposes to FIGS. 15-17, the compensation plates 120b may in an exemplary embodiment be created as integral portions of the top copper layer 120d and the bottom copper layer 120e. They provide compensation for both near end cross-talk (NEXT) and return loss (RL). The value of each of said capacitors is from 100 femto-farads to 3000 femto-farads, depending for example upon the design intent.

(29) In an embodiment, PCB 120 is located at a distal end (e.g., on the tips) of the plug contacts. The plug contacts are preferably relatively short in length, such that the compensation capacitance provided by the secondary PCB 120 is located in the immediate vicinity of the jack/plug interface. This location of the compensation capacitance is also specifically offset from or otherwise outside of the current path between the jack/plug interface and the plug cable. The connection between the compensation 120c and the plug contacts 130 is made by way of plated-through-holes 120a-1 through 120a-8.

(30) Separating the primary PCB 110 from the compensation PCB 120 simplifies the manufacturability, and further enables the use of different basic materials, overall thicknesses and dielectric constants across both of the PCBs. This may further result in better control of electrical properties on both PCBs and substantially eliminate the chances of unwanted electrical interactions.

(31) Within the primary PCB 110 are two or more horizontal ground planes 110g that provide electrical shielding and isolation between cable pairs 170 that are terminated to the top and bottom of the primary PCB. An additional vertical (i.e., orthogonal in orientation with respect to a surface plane of the primary PCB) shield 150 is attached to the primary PCB 110 and commoned to the ground plane(s) that reside in the primary PCB 110. This shield 150, composed of metal or other conductive substance, provides electrical shielding and isolations between cable pairs 170 that are terminated to the right and left sides of the primary PCB. This electrical shielding acts to mitigate exchange of high frequency electrical signals between cable pairs 170. Shield 150 is located by a plated-through-hole 110e and within an air-gap slot 110d. The air-gap 110d is arranged along a longitudinal axis of the primary PCB and in parallel with the adjacent conductor traces. This is done to avoid any inductive resonance coupling between the paths of the signal pairs.

(32) Referring to an exemplary embodiment as shown in FIGS. 11-14, the conductive paths between the cable solder pads 110a and the contact plated through holes 110b-1 through 110b-8 are shown s signal traces 110t. These are portions of both the top copper layer 110h and bottom copper layer 110k. For each signal pair, the traces 110t are located over a ground plane 110g in parallel orientation to generate controlled impedance zones 110i. The control is maintained by prescribing the width of the traces 110t, the spacing between the traces 110t and ground planes 110g.

(33) An exemplary embodiment of the front plug housing 107 is shown in FIG. 9. The plug latch 107a engages with the latching feature in standard jacks to provide easily accessible and positive connector engagement and retention. At the rear of the plug housing 107 are the entrances of the plug subassembly guide slots 107b. The terminated plug subassembly 108 is inserted into these slots. The slots locate and retain the subassembly 108 to ensure proper electrical and mechanical performance. When the subassembly 108 is fully inserted, the contact retainer latches 140a engage with the notches 107c in the sides of the front housing 107. This ensures retention and location of the subassembly 108. Additionally, these notches 107c engage with the shield tabs 106a when these are formed over. This further ensures that the fully assembled plug will have no chance of becoming disassembled during normal usage. Latching holes 107d are also provided to retain the main shield 106 and the front housing 107 during the manufacturing process and after final assembly.

(34) FIG. 10 shows the plug subassembly 108 terminated to the shielded twisted pair cable 104. Prior to termination, the strain relief and main shield are threaded over the end of the cable. Then the crimp ferrule 160a is also threaded over the end of the cable. These are then pushed up the cable and out of the way du ring cable preparation.

(35) An exemplary preparation sequence for the cable 104 may now be described. The cable jacket 104a is initially removed from the end of the cable 104, and the four twisted pairs 170 are separated. The shielding foil 170a is cut back from the ends of the pairs 170, and a short section of the wire insulation 170b is cut off, exposing the signal conductors 170c.

(36) After the cable 104 is prepared, the conductors 170c are arranged in the proper wiring pattern. The conductors 170c are terminated to the conductive pads 110a on PCB 110. For termination, the conductors are attached by means of welding, soldering or similar process. After the cable pairs are terminated to the primary PCB 110, the crimp ferrule 160a is pushed toward the plug subassembly 108. The crimp ferrule 160a is aligned pith the notch 150a in the vertical shield 150, and then crimped with an appropriate termination tool. Crimping of the crimp ferrule now 160b, acts to common the shielding of the twisted pairs 170a and the vertical shield of the plug subassembly 108 and thus to the ground plane(s) of the primary PCB 110.

(37) The terminated plug assembly 108 is then inserted into the slots 107b in the front housing 107. The subassembly is pushed forward until the latches 140a fully engage with the front housing notches 107c. The strain relief 105 and main shield 106 are then pushed up over the front housing 107 and latched in place. The plug is now fully assembled and ready for testing and use.

(38) Throughout the specification and claims, the following terms take at least the meanings explicitly associated herein, unless the context dictates otherwise. The meanings identified below do not necessarily limit the terms, but merely provide illustrative examples for the terms. The meaning of a, an, and the may include plural references, and the meaning of in may include in and on. The phrase in one embodiment, as used herein does not necessarily refer to the same embodiment, although it may.

(39) The term coupled means at least either a direct electrical connection between the connected items or an indirect connection through one or more passive or active intermediary devices.

(40) Conditional language used herein, such as, among others, can, might, may, e.g., and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

(41) The previous detailed description has been provided for the purposes of illustration and description. Thus, although there have been described particular embodiments of a new and useful invention, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the follow claims.