Methods of manufacture of communication connectors and communication connector circuits
09825406 · 2017-11-21
Assignee
Inventors
- Satish I. Patel (Roselle, IL)
- Robert E. Fransen (Tinley Park, IL)
- Frank M. Straka (Orland Park, IL)
- Melanie M. Hagar (Bartlett, IL)
Cpc classification
Y10T29/4913
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T29/49224
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H05K1/0228
ELECTRICITY
International classification
H01R43/20
ELECTRICITY
H01R13/66
ELECTRICITY
Abstract
Embodiments of the present invention generally relate to communication connectors, and methods of manufacture thereof and their components. In some embodiments, the methods focus on reducing the net effect on electrical performance of communication connectors from variation in manufacturing, where the connectors include multiple stages of capacitive coupling.
Claims
1. A method of manufacturing a communication jack including multiple stages of capacitive coupling, said method comprising the steps of: providing a first stage of said capacitive coupling via a first pad capacitor having a pair of first capacitor plates, each of said first capacitor plates having a substantially square shape; and providing a second stage of said capacitive coupling via a second pad capacitor having a pair of second capacitor plates, each of said second capacitor plates having a substantially rectangular shape where no two adjacent sides have substantially equal dimensions wherein said first stage of said capacitive coupling and said second stage of said capacitive coupling have opposite polarities, a magnitude of said first stage is greater than a magnitude of said second stage, dimensions of each of said second capacitor plates are selected such that a manufacturing variation from respective target dimensions of said first pad capacitor and said second pad capacitor maintain a net capacitive coupling within said communication jack such that said communication jack meets at least one of a CAT5E, CAT6, CAT6A, CAT7, and CAT7A standards, and wherein each of said first capacitor plates has dimensions X and X, and a surface area A given by A=X*X; wherein each of said second capacitor plates has dimensions Y and Z, and a surface area B given by B=Y*Z; wherein said communication jack meets at least one of a CAT5E, CAT6, CAT6A, CAT7, and CAT7A standards; wherein Z=√A±√(A−B); and wherein Y=√A∓√(A−B).
2. A method of manufacturing a communication jack comprising the steps of: providing a jack housing; positioning a plurality of plug interface contacts at least partially within said jack housing; positioning a plurality of insulation displacement contacts at least partially within said jack housing; and providing crosstalk cancellation circuitry between said plurality of plug interface contacts and said plurality of insulation displacement contacts, said crosstalk cancellation circuitry including: a first stage of capacitive coupling provided via a first pad capacitor having a pair of first capacitor plates, each of said first capacitor plates having a substantially square shape; and a second stage of capacitive coupling provided via a second pad capacitor having a pair of second capacitor plates, each of said second capacitor plates having a substantially rectangular shape where no two adjacent sides have substantially equal dimensions, wherein said first stage of capacitive coupling and said second stage of capacitive coupling have opposite polarities, a magnitude of said first state is greater than a magnitude of said second stage, and each of said first capacitor plates has dimensions X and X, and a surface area A given by A=X*X; wherein each of said second capacitor plates has dimensions Y and Z, and a surface area B given by B=Y*Z; wherein A and B are selected such that said communication jack meets at least one of a CAT5E, CAT6, CAT6A, CAT7, and CAT7A standards; wherein Z is selected such that Z=√A±√(A−B); and wherein Y is selected such that Y=√A∓√(A−B).
3. The method of claim 2, wherein said crosstalk cancellation circuitry is positioned on at least one printed circuit board.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:
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(21) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates preferred embodiments of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
(22)
(23) An exploded perspective illustration of the communication jack 44 is shown in
(24) As described above. PICs in the communication jack 44 have both an electrical function and a mechanical function. The PICs optimize electrical functionality through the design of the contact elements 46. The contact elements 46 have shorter lengths relative to the PICs of typical communication jacks as described above. The shorter lengths of the contact elements 46 result in reduced coupling between the contacts, as described above.
(25) However, for the illustrated example, the PICs must also provide a requisite contact normal force of about 100 grams on the plug contacts in the window of movement. The contact normal force is necessary to have a low-resistance interface for the communication plug. The PICs have improved mechanical functionality through the design of the mechanical spring elements 64. The mechanical spring elements 64 provide the communication jack 44 the requisite contact normal force between the PICs and the contacts of the plug 12.
(26) The tradeoff between the electrical and mechanical functionalities of the PICs is addressed through the use of the electrically insulating elements 62. The electrically insulating elements 62 connect the contact elements 46 to the mechanical spring elements 64. In this manner, the contact elements 46 are electrically insulated from the mechanical spring elements 64, meaning the mechanical spring elements 64 do not extend the electrical length of the PICs. Rather, only the contact elements 46 of the PICs operate as part of the electrical circuit in the communication jack 44. Thus, the communication jack 44 reduces crosstalk at the contacts while still providing the requisite contact normal force.
(27) As mentioned above, the contact elements 46 of each PIC are connected to the mechanical spring elements 64 via the electrically insulating elements 62. In some embodiments, the contact elements may be pivotally connected to the mechanical spring elements 64. Thus, the spring elements 64 may be made of a conductive material but still will not extend the electrical length of the PIC. Alternatively, the spring elements 64 may be made of a non-conductive material such that the electrically insulating elements 62 may be omitted.
(28)
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(30) The contact elements 46 may be manufactured using non-spring materials. As the mechanical spring elements 64 are electrically isolated from the contact elements 46, the mechanical spring elements 64 may be made longer to withstand the displacement of the contact elements 46 over a range of plug-contact crimp heights, including four- and six-position plug insertion. As a result of the electrically insulating elements 62, such an increase in the length of the mechanical spring elements 64 does not increase the electrical length of the PIC as a whole. This electrical isolation further essentially eliminates inductive and capacitive coupling between the mechanical spring elements 64 themselves.
(31) Referring to the more detailed view of
(32) In some embodiments, there may be eight PICs in the communication jack, as shown. Each of the PICs is identical and is formed in the same manner as the rest. As such, fabrication may be simplified. For example, the PICs may be stamped on one strip at 0.04 inches centerline. The shorter length of the PICs reduces the requisite strip width, and thus, overall material costs.
(33) The mechanical spring elements 64 are similar to one another. The mechanical spring elements 64 may be made from plastic resin or ferrous metal, or other metal, to help lower costs.
(34)
(35) In the expanded view, a plug contact 12 of the entering communication plug 6 is shown making contact with a contact element 46 of a PIC in the communication jack. The contact element 46 is connected to an electrically insulating element 62 of the PIC that is in turn connected to a spring element 64 of the PIC. The contact element 46 may be described as having a free end 74 and a spring end 76. The electrically insulating element 62 is then connected between the spring element 64 and the spring end 76 of the contact element 46.
(36) As the communication plug 6 enters, the plug contact 12 contacts the contact element 46 and forces the free end 74 of contact element 46 to rotate downwards like a lever. The spring end 76 of the contact element 46 contacts the horizontal rigid PCB 60 and in turn lifts up the insulating element 62, forcing the mechanical spring element 64 to move upward. The spring element 64 resists the upward motion, resulting in a contact normal force on the plug contacts 12. Thus, the mechanical integrity of the communication jack is enabled through the use of spring element 64.
(37) Further, it can be seen from the expanded view that the electrical length of the PIC includes only the length of the contact element 46. Thus, the electrical length can be understood as the distance 72 between the free end 74 of the contact element 46 and the spring end 76 of the contact element 46. In some embodiments, this distance may be around 0.115 inches, and more particularly can be less than 0.160 inches. As described above, this design of the communication jack allows for reducing a source of crosstalk in a mated communication plug over a range of signal operating frequencies.
(38) The horizontal rigid PCB 60 is designed to have the same thickness and core construction of the vertical rigid PCB 50. In this manner, the rigid PCBs may be fabricated together and may have compensating capacitors that change in the same manner. This helps improve production yield and allows the use of rigid PCBs, which reduces cost as compared to the flexible PCBs as used in other solutions. The horizontal rigid PCB 60 is connected to the vertical rigid PCB via right angle contacts 68 (shown in
(39) Compensation circuits used in embodiments of the present invention may contain capacitors whose size and shape are designed such that when they are subjected to variation in manufacturing from such sources as etching, the net effect on the electrical performance of the jack is minimized. The capacitors are labeled in the drawings according to the conductive traces to which they are connected. Thus, C46 is a capacitor between the 4.sup.th and 6.sup.th conductive trace.
(40) As is known in the art of PCB manufacturing, the etching of a PCB starts with a substrate with copper cladding, then a coating of etch resist is applied. Using the PCB artwork, the desired PCB pattern is imaged and developed, the PCB is then placed into a chemical bath for a specified period of time where the unwanted copper cladding is etched away, and the etch resist is stripped away leaving the final PCB artwork. Variations in any part of the process can create variations in the compensation capacitors. Examples of variation can be variation of the chemical composition of the chemical bath as a function of position within the bath, or exposure time variation of the PCB panel within the chemical bath, or copper cladding thickness variation.
(41) More specifically, for pair combination 45-36 (C35, C46, C34, C56) a design criteria referred to as scenario 2 is used; for pair combination 36-12 (C13, C16) the scenario 1 design criteria is used; for pair combination 45-12 (C25, C15) the scenario 1 design criteria is used; for pair combination 36-78 C68 is a square in a single first stage; for pair combination 45-78 both C58 and C47 are square in a single first stage; and for pair combination 12-78 no compensation is needed.
(42) To understand these scenarios, one must first understand that in many CAT6 and CAT6A jacks, a two stage compensation scheme is typically used where the first stage uses a capacitor of opposite polarity to the incident crosstalk caused by the plug, and the second stage uses a capacitor of the same polarity as the incident crosstalk caused by the plug. The first stage capacitor is typically larger than the second stage capacitor. The formula for capacitance between two plates is generally understood by the equation
C=∈.sub.r∈.sub.0A/d, (1)
where C is the capacitance in farads (F), ∈.sub.r is the relative dielectric constant of the material between the plates (typically about 4.4 when using FR4), ∈.sub.0 is permittivity of free space (8.85*10.sup.−12 F/m), A is the area of overlap of the two plates in square meters, and d is the distance between the two plates in meters.
(43) Thus, the net crosstalk on the jack used to cancel the crosstalk caused by the plug is approximately the difference between the two capacitors in the first and second stages (neglecting other parasitic crosstalk elements elsewhere in the jack, mutual inductive coupling, and the frequency dependency of the coupling). This can be written as
Cnet=Cstage 1−Cstage 2, (2)
where Cnet is the net capacitance, Cstage 1 is the capacitance in stage 1, and Cstage 2 is the capacitance in stage 2. Equation 1 shows that capacitance is proportional to area. Therefore, if one assumes that both capacitors are created on the same circuit board panel (thus the same etching, dielectric material, and separation),
Cnet˜Astage 1−Astage 2, (3)
which states that the net capacitance is proportional to the difference in the area of overlap of the plate capacitors comprising stage 1 and stage 2 (Astage 1 and Astage 2, respectively).
(44) Since the capacitors for stage 1 and stage 2 are made on the same panel, any over-etching or under-etching is assumed to affect both capacitors equally. Therefore, the change in net capacitance for a circuit board that is over-etched or under-etched is given by
ΔCnet˜ΔAstage 1−ΔAstage 2, (4)
where ΔCnet refers to the change in net capacitance, and ΔAstage 1 and ΔAstage 2 both refer to the change in area for stage 1 and stage 2, respectively. By selectively choosing the dimensions of the capacitors comprising stage 1 and stage 2, the overall ΔCnet can be minimized for different types of etching variation.
Four Scenarios
(45) In general, there are four scenarios that must be examined. For reference, a jack using 2 stages of compensation can have a variety of methods of doing this compensation. Assuming all compensating crosstalk (of opposite polarity of the incident crosstalk caused by the plug) is located in stage 1, and all intentional crosstalk (of the same polarity as the incident crosstalk caused by the plug) is located in stage 2, there are four unique scenarios that should be examined because for a given pair combination, there are four coupling mechanisms. For example, pair combination 45-36 can have coupling between 3-4 and 5-6 (crosstalk) and coupling between 4-6 and 3-5 (compensating crosstalk). The four scenarios come from the fact that stage 1 can have 1 or 2 compensating elements, and stage 2 can have 1 or 2 compensating elements (resulting in four combinations).
(46) For all scenarios addressed below, it is assumed that all capacitors are built with the same core thickness and, the same dielectric material, and are subject to the same over-etching or under-etching during PCB manufacturing. This assumption is reasonable if the capacitors are physically located near each other during PCB manufacturing (within a few inches). Additionally, these results assume no edge effects or other variations to the capacitance (i.e., equation 1 holds). These results can easily be slightly modified to account for the change in capacitance caused by capacitor edge effects, and/or other effects caused by distributed electrical parameters.
(47) Scenario 1: 1 Capacitor in Stage 1, and 1 Capacitor in Stage 2
(48) For this scenario, there is 1 capacitor in stage 1 and 1 capacitor in stage 2. The stage 1 capacitor is larger than the stage 2 capacitor. Due to the fact the stage 1 capacitor is larger, its area will vary more than the stage 2 capacitor for the same etching variation. Therefore, to minimize the change in the stage 1 capacitor 53 (see
(49) Therefore, since the effective areas of overlap (A (stage 1) and B (stage 2)) of these capacitors are known,
X*X=A, (5)
and
Y*Z=B. (6)
(50) Since the net capacitance (proportional to net area, Anet) between them is also set by the designer,
Anet, scenario 1 (ideal case)=A−B=X.sup.2−Y*Z. (7)
(51) Additionally, if we want to minimize the effect of etching, we can try to achieve the same Anet with an over-etching or under-etching of E (E will be positive with under-etching and negative with over-etching). This leads to the equation
Anet, scenario 1 (with etching error E)=(X+E).sup.2−(Y+E)*(Z+E)=X.sup.2−Y*Z. (8)
(52) Solving equations 5 with respect to X gives
X=√A. (9)
(53) Substituting this value of X into equation 8 gives
(√A+E).sup.2−(Y+E)*(Z+E)=(√E).sup.2−Y*Z, (10)
which can be expanded to
A+2*E*√A+E.sup.2−Y*Z−Z*E−Y*E−E.sup.2=A−Y*Z. (11)
(54) Cancelling identical terms on both sides of equation 11 gives
2*E*√A−Z*E−Y*E=0. (12)
(55) Dividing both sides of equation 12 by E yields
2*√A−Z−Y=0. (13)
(56) Substituting Y=B/Z (from equation 6) into equation 13, multiplying both sides of equation 13 by −1, and rearranging the terms, yields
Z−2*√A+B/Z=0. (14)
(57) Multiplying both sides of equation 14 by Z gives
Z.sup.2−2*Z*√A+B=0. (15)
(58) This is a quadratic equation which can be solved for Z as
Z=√A±√(A−B). (16)
(59) Similarly solving equation 13 for Y gives
Y=√A∓√(A−B). (17)
Also, X=√A (from equation 5).
(60) Note that depending on the sign used in equation 16, the opposite sign must be used in equation 17. Also note that in equations 9, 16, and 17 the etching factor, E, is no longer in these equations; consequently, for any change in etching, these equations hold true. Thus, the net capacitance will not change given any change in etching. Therefore, for a two-stage compensating scheme having a first stage compensating capacitor of area A=X.sup.2, a second stage of B=Y*Z (rectangle), with Anet, scenario 1 (with etching error E)=Anet, scenario 1 (ideal case), equations 9, 16, and 17 can be used to determine X, Y, and Z.
(61) Scenario 2: 2 Capacitors in Stage 1, and 2 Capacitors in Stage 2
(62) In this scenario there are two capacitors in stage 1, and 2 capacitors in stage 2. See
X*X=A, (18)
W*W=C, (19)
Y*Z=B, (20)
and
T*U=D. (21)
(63) For this scenario, Anet is equal to
Anet, scenario 2=A+C−B−D. (22)
(64) Since the net area needs to be the same before and after any etching effects E, substituting equations 18 to 21 into equation 22,
Anet, scenario 2 (ideal case)=X.sup.2+W.sup.2−Y*Z−T*U, (23)
and
Anet, scenario 2 (with etching error E)=(X+E).sup.2+(W+E).sup.2−(Y+E)*(Z+E)−(T+E)*(U+E). (24)
(65) Following a similar derivation as scenario 1, Y and Z can be solved for as
Y=√A+√C−(T+U)/2±√(((T+U)/2−√A−√C).sup.2−B), (25)
Z=√A+√C−(T+U)/2±√(((T+U)/2−√A−√C).sup.2−B), (26)
and
X=√A, W=C, and T*U=D (from equations 18, 19, and 21).
Note that Y and Z can both be interchanged.
(66) Thus, for given areas A, B, C, and D and given dimensions T and U, one can find a Y and Z that eliminate the effect of etching. Equations 25 and 26 are the most important and most universal equations for this as all other scenarios can be derived from these equations. Note that equations 16 and 17 can be derived from equations 25 and 26 by setting C, T, and U equal to zero.
(67) Under the special case where areas A=C and B=D, one can use equations 16 and 17 derived in scenario 1.
(68) Scenario 3: 2 Capacitors in Stage 1, and 1 Capacitor in Stage 2
(69) In this scenario, one can use equations 25 and 26 but set T and U (and consequently D) equal to zero.
(70) Scenario 4: 1 Capacitor in Stage 1, and 2 Capacitors in Stage 2
(71) In this scenario, one can use equations 25 and 26 but set C (and consequently W) equal to zero.
(72)
(73) Communication jack 78 includes, among other things, a housing 79 into which a communication plug 6 enters, a horizontal rigid PCB 84, and a vertical rigid PCB 82. A portion of communication jack 78 is expanded to illustrate the mechanical and electrical functionalities of the communication jack.
(74) In the second embodiment, contact between the horizontal rigid PCB 84 and the PICs of the communication jack is made through a clip-on style contact 90. In this embodiment, when the plug contacts 12 press downward on the contact elements 88 of the PICs, the PICs rotate around a centerline contact radius 92. Operation is as described above, with the contact normal force resulting from the resistance of spring elements 94. The PCBs 82, 84 can have compensation the same as, or similar to, that previously described for PCBs 50, 60, respectively.
(75) As described above, the contact elements 88 are respectively connected to the spring elements 94 via electrically insulating elements 96. In some embodiments, the electrically insulating element 96 may be omitted if the spring element 94 is made of or coated with an insulating material, such as insert-molded plastic or a powder coating.
(76) In the foregoing descriptions, the communication jack has been described as an RJ45 communication jack, such as a CAT6 or CAT6A jack. However, the invention described here is not limited to such an application. It may be applied just as well in other types and/or configurations of jacks or couplers. Other examples are possible as well.
(77) The present invention may be used in a communication system such as that depicted in
(78) The communication cables 108 may be unshielded twisted pair (UTP) cables, and more particularly. Category 6A cables that can operate at 10 GB/s. However, the present invention may be equally applied to or implemented in a variety of communications cables. Examples of possible communications cables include shielded cables, unshielded cables, CAT5E, CAT6, CAT6A, CAT7, CAT7A and other twisted pair Ethernet cables, and others. This list is not meant to be limiting, as other types of cables are possible as well.
(79) Some of the communication cables 108 may be terminated directly into the equipment 110, and others may be terminated into the communication jacks 106, communication plugs 6, or combinations thereof. The use of communication jacks 106 may eliminate the need for the foil labels 100, and may further improve ANEXT, as described above. Further, the communication cables 108 may be processed into looms, or bundles, of cables and may be processed into preterminated looms.
(80) Communication cables 108 may be used in a variety of structured cabling applications such as patch cords, zone cords, backbone cabling, and horizontal cabling, though the present invention is not limited to such applications. In general, the present invention may be used in military, industrial, telecommunications, computer, data communications, and other cabling applications.
(81) A method of manufacturing the communication jack described above is also contemplated. The method may include providing a PCB that includes one or more crosstalk compensation circuits, and contacting a PIC to a contact on the PCB. The PIC may, as described above, include a spring element, a contact element pivotally connected to the spring element, and an electrically insulating element that connects the contact element to the spring element. As in the above-described embodiments, the PCB may be a rigid PCB, and the contact on the PCB may contact the PIC at the interface of the contact element and the electrically insulating element.
(82)
(83) An exploded view of jack 138 can be seen in
(84) Like the jack previously described, jack 138 uses two rigid circuit boards 50, 60, and a separate spring 156 (
(85)
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(87) Alternatively, front sled assembly 142 can be modified to eliminate breakaway insulating caps 160. It may be advantageous to use an alternative front sled assembly 172 as shown in
(88)
(89) An exploded view of jack 238 is shown in
(90) Jack 238 of
(91) PICs 244 are not laminated PICs; instead they are free-body layered PICs. Each of the layers of fixed end 264 of PIC 244 (see
(92)
(93) In addition to simplified assembly, electrical performance benefits can be achieved by using the layered PIC design of jack 238.
(94)
(95) Referring now to
(96) Because PICs 332 are inserted into bottom side 336 of PCB 60A, the width of PICs 332 must be less than the diameter of holes 344. Therefore, to increase the width of PICs 332, holes 344 must also increase in diameter. Increasing PIC 332 width is mechanically and electrically advantageous as it increases PIC 332 stiffness, makes assembly handling easier, and provides lower electrical resistance. As the hole diameter increases, the edges of adjacent holes get closer in proximity unless holes 344 are staggered as shown in
(97)
(98) Alternative embodiments of features 342 may include compliant shape made using shearing, forming, or coining operations individually or combined.
(99) Other embodiments of the present invention can include PCB 60A and PCB 50A (see
(100) The schematic for rigid PCB 60A is shown in
(101) The schematic for the rigid PCB 50A is shown in
(102) An additional embodiment is to have the same stack-up type for the rigid PCB 60A and rigid PCB 50A (4-layer and 2-layer, respectively), but with a different overall thickness (different than 0.062″). Another embodiment includes a rigid PCB 60A with a different thickness than the overall thickness for rigid PCB 50A. Another embodiment includes a 4-layer stack-up for rigid PCB 50A. The 4-layer stack-up can be from the top table in
(103) Any of the embodiments of PCBs 50A and 60A can replace the PCBs 50 and 60, respectively.
(104) While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.