Patent Application
20160315409
The subject matter herein relates generally to electrical connector systems.
Some electrical connector systems utilize electrical connectors to interconnect two circuit boards, such as a motherboard and daughter card. Signal loss and/or signal degradation is a problem in known electrical systems. For example, crosstalk results from an electromagnetic coupling of the fields surrounding an active conductor (or differential pair of conductors) and an adjacent conductor (or differential pair of conductors). The strength of the electromagnetic coupling generally depends on the separation between the conductors, such that crosstalk may be significant when the electrical connectors are placed in close proximity to each other. Moreover, as speed and performance demands increase, known electrical connectors are proving to be insufficient. Additionally, there is a desire to increase the density of electrical connectors to increase throughput of the electrical system, without an appreciable increase in size of the electrical connectors, and in some cases, with a decrease in size of the electrical connectors. Such an increase in density and/or reduction in size causes further strains on performance.
In order to address performance, some electrical connectors have been developed that utilize shielding between pairs of signal contacts. The shielding is provided in both connectors along the signal lines, such as through ground contacts. Typically, the individual shields are electrically commoned in both circuit boards. However, the shields remain electrically independent between the circuit boards. The signal lines may experience degradation, such as resonance noise, along their lengths through the electrical connectors. The resonance noise is due to standing electromagnetic waves created at the ends of the ground contacts that propagate along the ground contacts and cause the electrical potential of the ground contact to vary along the length, referred to as resonance spikes. The resonance noise can couple to the pairs of signal contacts to degrade the signal performance. The resonance noise and crosstalk between pairs of signal contacts increases as the electrical connectors are used to convey more data at faster data rates and transmitted at higher frequencies. The resonance noise also increases as the length of the ground contacts between grounding locations increases.
A need remains for an electrical connector that reduces resonance noise to improve signal performance of an electrical connector system.
In an embodiment, an electrical connector is provided that includes a housing stack, signal and ground conductors, and a ground bracket. The housing stack comprises a front housing and a rear housing. The front housing defines a mating end of the housing stack. The rear housing defines a mounting end of the housing stack. The rear housing is positioned rearward of the front housing. The housing stack defines signal cavities and ground cavities that extend continuously through the front housing and the rear housing between the mating end and the mounting end. The signal conductors and ground conductors are held in the signal cavities and ground cavities, respectively, of the housing stack. The signal conductors are arranged in a plurality of signal pairs configured to carry differential signals. The ground conductors are interleaved between the signal pairs. The ground bracket is held in the housing stack between the front housing and the rear housing. The ground bracket is electrically conductive. The ground bracket engages and is electrically connected to each of the ground conductors to electrically common the ground conductors along a ground plane that is intermediate between the mating end and the mounting end.
In another embodiment, an electrical connector is provided that includes a housing stack, signal and ground conductors, and first and second ground brackets. The housing stack comprises a front housing, a spacer member, and a rear housing. The front housing defines a mating end of the housing stack. The rear housing defines a mounting end of the housing stack. The spacer member is disposed between the front housing and the rear housing. The housing stack defines signal cavities and ground cavities that extend continuously through the front housing, the spacer member, and the rear housing between the mating end and the mounting end. The signal conductors and the ground conductors are held in the signal cavities and ground cavities, respectively, of the housing stack. The signal conductors are arranged in a plurality of signal pairs configured to carry differential signals. The ground conductors are interleaved between the signal pairs. The first and second ground brackets are held in the housing stack. The first and second ground brackets are each electrically conductive. The first ground bracket is disposed between the front housing and the spacer member. The first ground bracket engages and electrically connects to each of the ground conductors to electrically common the ground conductors along a first ground plane. The second ground bracket is disposed between the spacer member and the rear housing. The second ground bracket engages and is electrically connected to each of the ground conductors to electrically common the ground conductors along a second ground plane that is spaced apart axially from the first ground plane. The first ground plane and the second ground plane are located between the mating end and the mounting end.
In an exemplary embodiment, the first electrical connector 102 is a receptacle connector, and is referred to herein as receptacle connector 102. In addition, the second electrical connector 102 is a header or mating connector in an exemplary embodiment, and is referred to herein as a header connector 104. Although one or more embodiments shown and described below describe the receptacle connector 102 as having an extended length due to multiple stackable modules (such as rear housings 138, for example), it is recognized that in an alternative embodiment, the stackable modules and/or other components of the receptacle connector 102 may be part of the header connector 104 instead of, or in addition to, being part of the receptacle connector 102.
The electrical connector system 100 may be disposed on or in an electrical component, such as a server, a computer, a router, or the like. The electrical component may include other electrical devices in addition to the electrical connector system 100 and located near the electrical connector system 100. Due to space constraints in or on the electrical component, it may be useful to vary the height of the electrical connector system 100 in order to vary the distance between the first and second circuit boards 106, 108. For example, one or more electrical devices disposed on or near the second circuit board 108 may contact the first circuit board 106, interfering with the mating between the receptacle and header connectors 102, 104, when the electrical connector system 100 has a first height. But, if the connector system 100 has a taller height such that the first circuit board 106 does not move as close to the second circuit board 108 during mating, the first circuit board 106 may be sufficiently spaced apart from the second circuit board 108 during mating such that the first circuit board 106 clears the one or more electrical devices on or near the second circuit board 108, allowing for unimpeded mating of the receptacle and header connectors 102, 104. In an embodiment, the receptacle connector 102 is modular in design, having any number of modules or units stacked together to adjust the height of the receptacle connector 102, and thus the height of the connector system 100. Alternatively, or in addition, the header connector 104 may be modular and have any number of stackable modules or units to adjust the height of the header connector 104.
In the illustrated embodiment, the header connector 104 includes a header housing 112 and a plurality of signal contacts 114 and ground contacts 116. The header housing 112 extends between a mating end 122 and a mounting end 124. The header housing 112 includes multiple outer walls 118 that define a socket 120 therebetween. The socket 120 is open at the mating end 122 of the header housing 112 and is configured to receive a portion of the receptacle connector 102 therein. The header housing 112 may be box-shaped with four outer walls 118. All or at least some of the outer walls 118 may be beveled at the mating end 122 to provide a lead-in section to guide the receptacle connector 102 into the socket 120 during mating. In the illustrated embodiment, the header housing 112 has a fixed height between the mating end 122 and the mounting end 124. The header housing 112 may be formed of at least one dielectric material, such as a plastic or one or more other polymers. The mounting end 124 of the header housing 112 faces, and may also engage, a surface 126 of the second circuit board 108.
The signal contacts 114 and ground contacts 116 protrude through a base wall 129 of the header housing 112 into the socket 120. The base wall 129 extends between the outer walls 118 and defines a back wall of the socket 120. The signal contacts 114 and the ground contacts 116 are formed of a conductive material, such as copper, a copper alloy, and/or another metal or metal alloy. In the illustrated embodiment, the signal contacts 114 and the ground contacts 116 each include a pin 128 that extends into the socket 120. Although not clearly shown in
The receptacle connector 102 includes a housing stack 130 that extends between a mating end 132 and a mounting end 134. The housing stack 130 is modular and includes at least a front housing 136 and a rear housing 138, which are stackable modules or units. The front housing 136 has a front side 140 that defines the mating end 132. A rear side 142 of the rear housing 138 defines the mounting end 134. The housing stack 130 extends along a stack axis 144. The rear housing 138 is positioned or located rearward of the front housing 136. As used herein, relative or spatial terms such as “top,” “bottom,” “front,” “rear,” “left,” and “right” are only used to distinguish the referenced elements and do not necessarily require particular positions or orientations in the electrical connector system 100 or in the surrounding environment of the electrical connector system 100.
In one embodiment, the housing stack 130 may include only the front housing 136 and the rear housing 138, such that no other modules or units of the housing stack 130 separate the front housing 136 from the rear housing 138. In other embodiments, however, the housing stack 130 may include more than one rear housing 138, such that the housing stack 130 includes at least one intermediary rear housing 138 located between the front housing 136 and the rear housing 138 in the housing stack 130. As used herein, each intermediary rear housing 138 is referred to as a “spacer member,” since the intermediary rear housings 138 increase the length of the housing stack 130. The spacer members 138 may be substantially identical to the rear housing 138, such that each spacer member 138 and the rear housing 138 may have substantially the same shape, size, and/or composition. For example, the front housing 136, the rear housing 138, and the spacer members 138 may be composed of one or more dielectric materials, such as a plastic or one or more other polymers. In addition, the rear housing 138 and the spacer members 138 may be formed by the same process, such as by being molded using the same mold. In an alternative embodiment, the rear housing 138 is not substantially identical to the spacer members 138.
The housing stack 130 may include zero spacer members 138, one spacer member 138, or two or more spacer members 138 between the front housing 136 and the rear housing 138. In the illustrated embodiment, the housing stack 130 includes two spacer members 138, such that a first spacer member 138A is positioned between the front housing 136 and a second spacer member 138B, and the second spacer member 138B is positioned between the first spacer member 138A and the rear housing 138C.
The housing stack 130 defines signal cavities 146 and ground cavities 148 that extend through the housing stack 130 between the mating end 132 and the mounting end 134. The signal cavities 146 and the ground cavities 148 extend continuously through the modules of the housing stack 130, including through the front housing 136, the rear housing 138, and any intervening spacer members 138. The signal and ground cavities 146, 148 are shown in more detail in
The signal conductors 150 and the ground conductors 152 may extend for at least most of the length or height of the housing stack 130 between the mating end 132 and the mounting end 134. The signal conductors 150 and the ground conductors 152 may extend parallel to the stack axis 144. In the illustrated embodiment, the signal and ground conductors 150, 152 each have a terminating interface 158 that extends beyond the rear side 142 of the rear housing 138 at the mounting end 134 for electrical termination to corresponding conductors (not shown) on the first circuit board 106. The terminating interface 158 may be an eye-of-the-needle pin (shown in more detail in
In an embodiment, the receptacle connector 102 further includes at least one ground bracket 160 held in the housing stack 130 between the front housing 136 and the rear housing 138. Each ground bracket 160 is electrically conductive. Each ground bracket 160 extends transverse to the stack axis 144. For example, ground brackets 160 may be oriented orthogonal or perpendicular to the stack axis 144. The one or more ground brackets 160 are configured to engage and electrically connect to each of the ground conductors 152 to electrically common the ground conductors 152 along a ground plane. In an embodiment, the receptacle connector 102 includes multiple ground brackets 160 that are spaced apart from one another axially along the length of the ground conductors 152 (and along the height of the housing stack 130) in order to electrically common the same ground conductors 152 at multiple axial locations.
The ground conductors 152 are configured to provide shielding between the signal pairs of signal conductors 150 along the length (or height) of the housing stack 130. The individual ground paths formed by the ground conductors 152 and the corresponding ground contacts 116 of the header connector 104 may be electrically commoned in both circuit boards 106, 108. The ground brackets 160 provide ground planes to common the ground conductors 152 between the circuit boards 106, 108. Electromagnetic interference (EMI), such as resonance noise and crosstalk, between pairs of signal conductors 150 generally increases with increasing data transfer rates, frequencies, and lengths of the ground paths between grounding locations. Such resonance noise and crosstalk may degrade the signal integrity and performance of the electrical connector system 100. In an embodiment, the one or more ground planes provided by the one or more ground brackets 160 are each a grounding location, which reduces the ground path length between grounding locations, thereby improving signal integrity by reducing resonance noise and crosstalk within the connector system 100. For example, shortening the ground path length of the ground conductors 152 may reduce the magnitude of resonance peaks in resonance waves that propagate through the ground conductors 152 within the receptacle connector 102.
In addition, ground path length affects the resonance frequency of the ground conductors 152. A longer ground path length corresponds with a relatively lower resonance frequency, while a shorter ground path length corresponds with a relatively higher resonance frequency. Shortening the ground path length via the one or more ground brackets 160 may increase the resonance frequency to a level outside of a desired operating frequency range or band. For example, the resonance frequency may be increased to a level at which the resonance frequency does not have a detrimental effect on the signal performance of the signal conductors 150. The resonance frequency may be increased to a level at or above 12 GHz, 16 GHz, 20 GHz, or the like.
The ground brackets 160 are held between the two adjacent modules of the housing stack 130. For example, in an embodiment in which the housing stack 130 does not include any spacer members 138, a single ground bracket 160 may be located at the interface between the front housing 136 and the rear housing 138. In another example, if the housing stack 130 includes one spacer member 138, a first ground bracket 160 may be disposed at the interface between the front housing 136 and the spacer member 138, and a second ground bracket 160 may be disposed at the interface between the spacer member 138 and the rear housing 138. Therefore, the first ground bracket 160 is spaced apart from the second ground bracket 160 along the height of the housing stack 130. The first ground bracket 160 engages and electrically connects the ground conductors 152 along a first ground plane, while the second ground bracket 160 engages and electrically connects the ground conductors 152 along a second ground plane that is spaced apart axially from the first ground plane. Both the first ground plane and the second ground plane are located between the mating end 132 and the mounting end 134 of the housing stack 130. In an embodiment, the first ground plane and the second ground plane are both parallel to the mating end 132 and the mounting end 134.
In the illustrated embodiment shown in
The signal and ground conductors 150, 152 are electrically conductive and are formed of a conductive material, such as copper, a copper alloy, silver, or another metal or metal alloy. The signal and ground conductors 150, 152 may be stamped and formed from a sheet or panel of metal. The signal conductors 150 and ground conductors 152 each include a mating interface 162, the terminating interface 158, and a stem 164 that extends between the mating interface 162 and the terminating interface 158. In an embodiment, the mating interface 162 of each of the signal conductors 150 and the ground conductors 152 is a tuning-fork style interface that is configured to engage a corresponding pin 128 (shown in
As shown in
In an exemplary embodiment, at least one edge 174 of each slot 172 of each ground bracket 160 is configured to engage the corresponding ground conductor 152 that extends through that slot 172 to provide an electrical connection between the ground bracket 160 and the corresponding ground conductor 152. Since each of the slots 172 of a corresponding ground bracket 160 engage a different ground conductor 152, the ground bracket 160 creates a conductive ground circuit along the ground plane 168 that electrically commons each of the ground conductors 152 engaged by the edges 174 of the slots 172. In an embodiment, the windows 170 are sized larger than the signal cavities 146 such that a clearance exists between edges of the windows 170 and the corresponding signal conductors 150 that extend through the windows 170. The ground bracket 160 as a result does not directly engage the signal conductors 150 to avoid producing an electrical short or other damage.
In the illustrated embodiment and other embodiments in which the receptacle connector 102 includes multiple ground brackets 160, the ground conductors 152 are electrically connected to different ground brackets 160 at different locations along the length of the ground conductors 152. For example, the first ground bracket 160A (between the front housing 136 and the first spacer member 138A) engages the stems 164 of the ground conductors 152 at a first location proximate to the mating interface 162. The second ground bracket 160B (between the first spacer member 138A and the second spacer member 138B) engages the stems 164 of the ground conductors 152 at a second location that is more proximate to the terminating interface 158 than the proximity of the first location to the terminating interface 158. The third ground bracket 160C (between the second spacer member 138B and the rear housing 138C) engages the stems 164 at a third location that is more proximate to the terminating interface 158 than the proximity of the second location (and the first location) to the terminating interface 158. Thus, the ground conductors 152 are each electrically commoned at three different locations along the length of stem 164 within the housing stack 130 via the ground brackets 160A-160C (in addition to grounding that occurs between the terminating interfaces 158 via the first circuit board 106 (shown in
In an embodiment, the signal conductors 150 and the ground conductors 152 each include at least one T-shaped stop shoulder 176 that is used to retain the respective conductor 150, 152 in a designated axial position within the housing stack 130. In the illustrated embodiment, the stop shoulders 176 of the signal and ground conductors 150, 152 are integral to the conductors 150, 152 and are located on the stems 164 proximate to the mating interfaces 162. The stop shoulders 176 may be sandwiched between the front housing 136 and the first spacer member 138A to lock the axial position of the conductors 150, 152. Optionally, the stop shoulders 176 of the ground conductors 152 are configured to engage the first ground bracket 160A, while the stop shoulders 176 of the signal conductors 150 do not engage the first ground bracket 160A, engaging the first spacer member 138A instead. As shown in
The signal cavities 146 and the ground cavities 148 are arranged in plural columns 184. Six columns 184 are shown in
Referring now specifically to
The front side 198 of the rear housing 138 optionally includes multiple lugs 210 that protrude from the front face 200 proximate to at least one of the outer walls 208. In
Optionally, the rear housing 138 also defines at least one shelf 212 that is recessed from the front face 200. Each shelf 212 may extend proximate to an outer wall 208. In
The ground bracket 160 includes the windows 170 and the slots 172. The windows 170 and slots 172 are arranged in multiple, staggered columns 220 that align with the columns 184 (shown in
In the illustrated embodiment, two ground brackets 160 are held in the housing stack 130 between the stackable modules. Each of the ground brackets 160 has a planar body 214 that includes a first side 216 and an opposite second side 218. A first ground bracket 160A is located between the front housing 136 and the spacer member 138A, and a second ground bracket 160B is located between the spacer member 138A and the rear housing 138C. In an embodiment, the first side 216 of the first ground bracket 160A abuts the rear face 188 of the front housing 136, and the second side 218 of the first ground bracket 160A abuts the front face 200 of the spacer member 138A. In an alternative embodiment with no spacer members 138, the first ground bracket 160A is the only ground bracket 160, and the second side 218 of the ground bracket 160 abuts the rear housing 138C directly. Referring now back to the illustrated embodiment, the first side 216 of the second ground bus 160B abuts a rear face 228 of the spacer member 138A along the rear side 142 of the spacer member 138A, and the second side 218 of the second ground bus 160B abuts the front face 200 of the rear housing 138C (or another intervening spacer member 138). The rear face 228 of the spacer member 138A (and/or the rear housing 138C) may be similar to the rear face 188 of the front housing 136 that is shown in
During assembly, the first and second ground brackets 160A, 160B may be placed onto the front faces 200 of the spacer member 138A and the rear housing 138C, respectively. Then, the housing modules are stacked upon one another such that the ground brackets 160 are sandwiched between the housing modules. The lugs 210 of the rear housing 138C are received in the pockets 230 of the spacer member 138A, and the lugs 210 of the spacer member 138A are received in the pockets 192 of the front housing 136. Although not shown, mechanical fasteners and/or chemical adhesives may be used to secure the housing modules to one another after or while the housing stack 130 is formed. For example, latches, clamps, screws, bolts, and other mechanical fasteners may be installed to secure the front housing 136, the rear housing 138, and any intervening spacer members 138 together. Adhesives such as glue and tape may be used instead of or in addition to the mechanical fasteners.
Referring now to
Optionally, as shown in
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
