The present invention relates generally to high speed pluggable connectors, and more particularly, to shielded, pluggable connectors with improved cooling capabilities.
Moore's Law, which is more properly termed an observation, is based on the understanding that in the field of integrated circuits, the complexity (or number of circuits) will double every two years. The fact that this observation has held true since about 1965 has had a remarkable impact on the world as we know it. Computation speeds that were in the realm of science fiction have become a reality. Moore's Law, as it is known, continues and while there appear to be fundamental physical limits to how small an integrated circuit can be made, other technologies may provide substitutes that allow the effect (the doubling of performance every two years) to continue for the foreseeable future.
One consequence of the increase in performance is that data needs to be transmitted at increasing rates. Data transmission rates that were unthinkable just a few years ago are a current reality and faster data transmission speeds are being planned into next generation products. For example, current data transmission rates that are used in the telecommunications industry are 12 to 15 Gbps (gigabits/second) and rates of 25 to 30 Gbps are already on the horizon. The increase (or desire for an increase) in data transmission rates affects the entire data infrastructure. For example, as part of their computer network companies will often employ servers and routers (which may be referred to as data-handling devices) so that computers in the company can communicate and access data in a desirable manner. These data-handling devices can be connected together by cable assemblies which utilize two plug connectors terminated to a length of cable. The plug connectors often take the form of electronic, pluggable modules that are inserted into an opening in the data-handling devices so as to mate with and engage an opposing mating connector. Within the data-handling devices, connectors are mounted to a circuit board and a cage typically surrounds the connector. The cage defines a hollow enclosure that envelops the component connector and within the enclosure, a module-receiving channel or bay is defined so that a module can be inserted into the channel. In operation, this allows the two data-handling devices to communicate with each other at high data rates.
The shielding provided by the cage is used to reduce electromagnetic interference (EMI) that may be emitted, for example, from other nearby connectors. Because of the high frequencies used to transmit the date, it is desirable to make the cage continuous so that no openings are provided to allow for high-frequency signals to enter and affect the intended signals moving through the connectors. However, with the increase in shielding comes a resultant poor airflow over the module. This lack of air-flow can create problems because at higher data rates the amount of energy passing through the connector increases and the increased energy increases the amount of heat that the connector has to dissipate. While the use of a heat sink has helped address this heat dissipation issue, one configuration that has been difficult to address is a stacked connector configuration is used. While air can be directed over the top of a stacked connector (the top of which can readily include a heat sink with fins to help dissipate heat), the lower connector is effectively sandwiched between an insulating circuit board and a heat generating module, making cooling particularly challenging. A known solution to this type of problem has been to mount the connectors belly to belly with heat sinks on opposite sides of the cages. As can be appreciated, however, this creates problems in plugging in modules because some modules will need to be turned upside down and it can be difficult to tell which way to turn the module when a person is facing a number of rows of such connectors. Furthermore, the split orientation of the connectors limits the interface with the circuit board that supports the connectors. Therefore, improvements in connector designs that could accommodate high heat loads would be appreciated.
In an embodiment, a cage with improved cooling capability is provided for a stacked connector. The cage is formed from a plurality of walls including a top wall, a bottom wall, two side walls and a rear wall. These walls cooperatively define a hollow enclosure with an interior space that envelops a housing. The hollow enclosure is divided into at least an upper and lower bay and includes a central portion positioned between the upper and lower bay and defined, at least in part by a spacer. In operation, a pluggable module can be inserted into the bays so that an edge-card can be inserted into the corresponding slot(s) and contact pads on the edge card can engage terminals supported by the housing. The central portion includes a front face with apertures so that air can be drawn into the center portion through the front face. The side walls include apertures aligned with the center portion so that air can be drawn out of the center portion. In this manner, when the cage is positioned in an enclosure that has a negative internal pressure, air will flow through the apertures in the front face and out the apertures in the side wall so as to provide cooling. In an embodiment, the cage may be a ganged cage with two or more sets of upper and lower bays positioned side by side and separated by a dividing wall. The dividing wall may also have apertures aligned with the center portion so as to facilitate air flow into and out of the center portion in a desired manner.
In the following detailed description, reference will be made to the following drawings wherein like reference numbers refer to like parts and wherein,
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.
Before looking at the figures, it should be noted that a number of different methods of assembling walls together to form the cage assembly. In general, a stacked cage assembly may include a first wall and a second wall that are used to form sides of the cage assembly. The cage assembly may further include a third wall that extends between the first and second wall to form a top of the cage assembly. A fourth wall may extend between the first and second wall to form a back wall. A fifth and sixth wall may be positioned so as to extend between the first and second wall in an orientation that is substantially parallel to each near the middle of the first and second wall (thus helping to form a first channel above the fifth wall and a second channel below the sixth wall, the first and second channel opening in a front of the cage assembly). The sixth wall is positioned below the fifth wall and includes an aperture so that a module inserted in the second channel is in communication with a space between the fifth and second wall. The aperture may be configured to provide an open area of at least 250 mm2 and in an embodiment may provide about 360-380 mm2. The percentage of area of the aperture to the area of the sixth wall may be greater than twenty five (25) percent and in an embodiment the aperture may cover between about thirty five (35) and fifty (50) percent of the area covered by the portion of the sixth wall that forms part of the second channel. As can be appreciated, this provides a substantial opening that allows for a significant level of convective heat transfer.
As is discussed below, an insert may be positioned between the fifth and sixth wall and the insert may be a dielectric. If used, the insert provides openings that allow air to flow past the insert into the space between the fifth and sixth wall. When the cage assembly is mounted in a bezel, openings in the bezel will allow air to flow through past the bezel, past the insert (if provided), over the aperture in the sixth wall (thus causing heat to convect away from a module inserted in the second channel) and then pass out through side apertures in the first and second wall. To promote good air flow patterns, the side apertures may be positioned so that for a given channel length, they are not positioned in the first third portion of the channel. As can be appreciated, therefore, this creates a triangular arrangement between the front openings, the aperture in the fifth wall and the side apertures. If the connector is positioned in an enclosed container and a negative pressure is provided on the interior of the container (e.g., by using a fan to push or pull air out of the container), air will flow through the front opening, over the module and out the side apertures. Thus, the space between the fifth and sixth wall can function as a plenum. As can be appreciated, in a ganged connector configuration, the air will pass through the middle plenum and into the two surrounding plenums before exiting the cage assembly. Thus, a relatively efficient air-flow pattern is possible that can provide good cooling without higher airflow rates.
The second channel can be defined as having a length that extends from the front of the cage to a portion of the connector that supports connector slots. To improve the effectiveness of the air flow, as noted above, the side apertures may be positioned so that they are not in the first third portion of the channel. In an embodiment, the side apertures may start at the midpoint of the channel and in another embodiment may be at least 60 percent of the channel length away from the front of the channel.
It has been determined that while the cooling is generally beneficial, a cage assembly configured to provide the described air-flow configuration is beneficial when the module is generating more than 1 watt of heat. Furthermore, as the heat load increases, the need for a cooling system such as is depicted increases. To handle higher heat loads such as two or three watts, significant air flow is still beneficial. In an embodiment, a ganged connector (such as depicted in
Turning now to the figures,
In order to provide shielding against EMI, the connector assembly 100 also includes a cage 120 that encloses the housings 102 and which defines a plurality of bays 130, each of which is sized to receive a single electronic module therein. As used herein, herein, the term “module” is intended to be synonymous with “plug connector”. As depicted, the number of bays 130 is equal to the number of card-receiving slots 108 in the connectors 102 of the assembly 100.
Returning to
The cover member 122 has three walls, a top wall 122a and two side walls 122b, 122c. The cover member 122 may include tail portions 126 in the form of compliant pins are formed as part of the cover member 122 and which are received within vias, or other openings on a circuit board so as to connect the cage to ground circuits on a circuit board. The tail portions 126 fit through slots 121a that are disposed in the base member 121. The base member 121 may include sidewall portions 121b, 121c that engage the cover member 122 to form a hollow enclosure. It should be noted, however, that the cage may omit the bottom wall in certain embodiments and could be formed of a single member, or any desired number of members, to form the cage that encloses the housings therein.
The rear member 123 of the cage 120 may also include sidewalls 123a, 123b that extend forwardly and engage the cover member 122. This rear member can be assembled onto the cover member 122 after the connectors 102 are inserted into the hollow enclosure formed by the cover and base members. Two divider walls 124 are shown in the illustrated embodiment that are provided to divide the hollow enclosure into three vertically-oriented sub-spaces, or compartments 129, that are arranged in side by side order. Each of these sub-spaces is further divided into two distinct bays 130 by the spacer 125 that extend transversely between the walls that form the compartment 129. In instances where only a single housing 102 is to be enclosed with a cage, no divider wall is used and one spacer 125 can be used and it would extend between the sidewalls 122b, 122c of the cage. In instances of a ganged connector assembly, such as the 2×3 ganged cage illustrated in
In order to facilitate assembly, the divider wall 124 may be formed with engagement tabs 124a and the like that are project outwardly therefrom and which are received in slots 122d, 121a that are disposed respectively in the cover member 122 and base member 121.
As depicted in
As is known in the art of SFP type connectors, each bay 130 receives a plug connector in the form of an electronic “pluggable module” that is inserted into the bay from the front of the connector assembly 100. The pluggable module typically includes a circuit card projecting form a free end that is received within the connector card-receiving slots 108 so that the terminals 110 of the terminal assemblies engage and connect to contact pads disposed on the circuit card, preferably along its leading edge.
During high speed data transmission, the connectors and modules generate heat. Excessive heat can be harmful to electronic components so operators seek to control the heat generated by operation of routers and sensors using these connectors and modules and dissipating it. One solution is attaching heat sinks to the modules themselves. However, this would necessitate removing part or a substantial portion of the cage cover member 122. Making an opening in the cover member 122 could eliminate a large portion of the EMI shielding capability of the cage for the upper module-receiving bay. However, even utilizing a heat sink in such a manner would not provide a solution to heat dissipation for the lower module inasmuch as the module in the lower module-receiving bay 130b could not be contacted by the heat sink. Due to its location and the fact the cage is mounted to a circuit board, it is impractical to attach a heat sink to the bottom module.
In order to help overcome this problem, air flow through a central portion of the connector can be beneficial. In an embodiment, a connector utilizes a network of air flow openings arranged in the connector assembly 100 that cooperatively provide a cooling network of passages that are disposed throughout the connector assembly 100 in proximity to the modules in both the upper and lower bay 130a, 130b. As shown in
The center portion 232 extends lengthwise of the connector assembly 100 from the front openings 132 of the bays 130 to the front face of the connectors 102, as well as widthwise between adjacent divider walls 124 or divider walls 124 and the side walls 122b, 122c and thus provides an air flow passage 150 through the middle of the connector assembly. The openings 140 in the side walls and/or the divider walls communicate with this air flow passage 150 and provide a means for either conventional convection cooling or forced air cooling due to an air pressure differential. As shown in
In order to preserve the amount of space available for the openings 140, the spacer 125 can be provided with its own openings 144 and these openings can be disposed in the side member 227 of the spacer 125. Although it is preferred that the spacer openings 144 are substantially matched (or aligned) with the openings 140 of the side or divider walls, 122b, 122c, 124, such alignment is not required and there may be a certain amount of offset, as is illustrated in
An insert 136 may be provided for use with each housing 102 (if, for example, the front face 128 is not integrated into the spacer) and as such, the insert 136 is preferably dimensioned to fit within the air flow passage 150 at the front end, or entrance 132, of each module-receiving bay 130 of the connector assembly 100. The insert 136 may be formed of a conductive material such as a die-cast metal or it may be a plastic resin that is plated with a conductive materials. As shown in
The electronic module that will be received within the top module-receiving bay will tend to lie flat on the floor of the bay (i.e., the top wall of the spacer 125) and so make direct contact therewith. Heat may then be transferred form the electronic module directly to the cage by conduction. The openings formed in the cage and communicating with the air flow passage 150 will permit the flow of air through this area, which in turn will the thermal energy conducted to the cage to be removed by convection cooling.
In order to provide cooling for the modules received within the bottom module-receiving bays 130b, the bottom wall 226 of the spacer 125 can have a large opening 160 formed therein. As best illustrated in
As mentioned above, the spacer 125 is provided with a plurality of engagement tabs 228a that project outwardly therefrom and which are used to engage any one of the upstanding walls. In order that the spacers 125 may be used adjacent each other in ganged cage applications, the opposing edges 237, 238 of the spacer 125 are patterned in an alternating pattern of engagement tabs 228a and clearance slots 236. For every engagement tab 228a present on one edge 237 of the spacer 125, there is a notch, or clearance slot 236 disposed on the opposing edge 238 of the spacer 125. These engagement tab-clearance slot combinations are aligned with each other widthwise with respect to the spacer 125. This relationship is best illustrated in
With the slots opposing the engagement tabs, they fit into the clearance slots when folded over an divider wall 124 so that the spacers 125 can be arranged in a pattern close to each other and be separated only by the thickness of the intervening, divider wall 124. In this manner, and as illustrated in
As shown in
A fifth wall 305 and sixth wall 306 are spaced apart and in conjunction with spacer wall 324, form a first channel 360 and a second channel 361 that are separated by the space between the fifth and sixth wall 350, 306. As can be appreciated from
As can be appreciated, from
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.
This application is a national phase of PCT Application No. PCT/US2010/026650, filed Mar. 10, 2010, which in turn claims priority to U.S. Provisional Application No. 61/159,029, filed Mar. 10, 2009, both of which are incorporated herein by referenced in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2010/026650 | 3/9/2010 | WO | 00 | 11/22/2011 |
Number | Date | Country | |
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61159029 | Mar 2009 | US |