High performance stackable connector

Abstract

A stacked I / O connector for use with a high-speed, high-density transceiver that generates substantial amounts of heat. The connector may be formed with a netted housing into which the lead frame assembly is inserted. The mesh housing may have openings in the front, rear, top, and / or side portions, enabling airflow to pass through the connector with small resistance. The sidewall opening may open into a passage between the housing and the wall of the cage, enabling air flowing to cool the transceiver inserted in the cage to pass through the connector assembly with low resistance and high cooling efficiency. The cage for the connector may be open that is selectively positioned such that air flowing through the cage to cool a transceiver mating with the I / O connector may pass through the connector with low resistance, thereby improving cooling efficiency. The connector can be used together with an OSFP transceiver so as to meet the signal integrity and heat dissipation requirements at the rate of 112 GBps and above.

Description

[0001] This application is a divisional application of the Chinese invention patent application filed on September 24, 2020, with application number 202080082425.5 and named “High Performance Stackable Connector”. Background Art

[0002] An electronic system may include two or more electronic devices connected by a cable. These devices may have an input / output (I / O) connector for connecting to a plug connector at the end of the terminated cable. The cable may be configured to carry electrical signals or optical signals. For transmitting optical signals, a transceiver is provided at one end of the cable to convert the optical signal into an electrical signal. A transceiver may also be provided for a cable carrying an electrical signal, because the signal may be amplified or converted between a signal format used on the cable and a signal format used within the device.

[0003] Plugs and I / O connectors can be constructed according to standards that enable components from different manufacturers to mate. For example, the Quad Small Form Factor Pluggable (QSFP) standard defines a compact, hot-swappable transceiver for data communications applications. The form factor and electrical interface are specified by a multi-source agreement (MSA) hosted by the Small Form Factor (SFF) committee. Components manufactured according to the QSFP standard are widely used to interface network hardware (such as servers and switches) to fiber optic cables or active or passive electrical connections.

[0004] The QSFP plug mates with a socket that is typically mounted on a printed circuit board (PCB). To block electromagnetic interference (EMI), the socket may be located within a metal cage that is also mounted to the PCB. The socket is typically indented from the edge of the PCB and located at the rear portion of the cage. The front portion of the cage typically extends through the panel of the electronic device and has an opening for receiving the QSFP transceiver. A channel extends from the opening at the front portion of the cage toward the rear portion to guide the transceiver into engagement with the socket. This arrangement can be used to connect a circuit board within an electronic device to an external device using a cable.

[0005] Transceivers used to convert optical signals into electrical signals can consume a large amount of power and therefore generate a large amount of heat. For example, a QSFP transceiver may consume 12 watts (W) of power. Transceivers that handle more signals, such as transceivers manufactured according to the QSFP-DD standard, may consume up to 15W. Large amounts of heat may cause the temperature surrounding the electronic, optical, or other components to exceed the rated operating temperature, causing errors during operation or reducing the useful life of the components. The heat generated by the transceiver can be evacuated by using a cooling fan that moves air over the metal cage. A heat sink can be mounted on the outside of the cage to further evacuate the heat of the transceiver.

[0006] Similar issues of high heat generation in a small area also occur in other form factors, such as OSFP, where each transceiver is expected to generate 7.5W to 15W of heat.

[0007] In some systems, two or more transceivers are arranged close to each other. The I / O connector can be configured in a "stacked" configuration to support the use of multiple transceivers. For example, an upper transceiver and a lower transceiver can be stacked in a cage to form a dual-stack connector. Summary of the invention

[0008] In one aspect, the present invention is directed to an I / O connector that includes one or more features to improve thermal and / or electrical performance when used with an OSFP or similar transceiver.

[0009] In one aspect, a stacked connector may include a housing and a plurality of conductive elements. The housing may have a first side wall and a second side wall opposite to the first side wall; a mating surface extending between the first side wall and the second side wall, the mating surface including a first slot and a second slot; a mounting surface perpendicular to the mating surface and extending between the first side wall and the second side wall; a top surface opposite to the mounting surface and extending between the first side wall and the second side wall. One of the plurality of conductive elements may include a mating contact portion, a contact tail, and an intermediate portion connecting the mating contact portion and the contact tail. The mating contact portion may be exposed within the first slot and the second slot. The contact tail may be exposed at the mounting surface. At least one of the first side wall or the second side wall may include a section adjacent to the mounting surface, and a portion extending from the section to the top surface. The portion may include at least one airflow opening passing therethrough.

[0010] Another aspect relates to a method of operating an electronic device, the electronic device comprising: a housing including a panel having an opening therethrough; an I / O connector assembly including a connector mounted to a printed circuit board and a cage and exposed through the opening in the panel, wherein the cage includes at least one channel; and a transceiver positioned within a channel of the at least one channel, the method comprising: operating the transceiver at a data rate exceeding 110 Gbps; and exhausting air from the housing to induce air flow along a path through the cage, the path including through the opening in a side wall of the connector and through a segment of the channel between the side wall of the connector and the side wall of the cage.

[0011] In another embodiment, a stacked connector, which is a type having a mounting surface, a mating surface perpendicular to the mounting surface, and a side surface perpendicular to the mating surface and the mounting surface, may include: a housing and a plurality of lead assemblies. The housing may include at least a first slot portion and a second slot portion, wherein each of the first slot portion and the second slot portion includes a slot passing therethrough and a wall defining the slot. Opposite first and second side walls may define a chamber within the housing. The first and second side walls support the first and second slot portions at the mating surface, so that at least 50% of the mating surface of the housing between the first slot portion and the second slot portion is open to a passage for air to enter the chamber. A plurality of lead assemblies may be within the chamber, and each of the plurality of lead assemblies may include a plurality of conductive elements.

[0012] The above is a non-limiting summary of the present invention, which is defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A is a simplified diagram of an electronic device including a stacked I / O connector within a cage;

[0014] Figure 1B is a perspective view of an alternative embodiment of a cage for stacked I / O connectors;

[0015] Figure 1C is a perspective view of a transceiver with an integrated heat sink that can be inserted into Figure 1B in the passage of the cage;

[0016] Figure 2A is a rear perspective view of the stacked I / O connector;

[0017] Figure 2B yes Figure 2A A front perspective view of a stackable I / O connector;

[0018] Figure 3 yes Figure 2A A partially exploded view of a stacked I / O connector with a lead frame assembly removed from a housing;

[0019] Figure 4 yes Figure 2A A rear perspective view of a stacked I / O connector showing an angle A of a middle portion of an upper lead frame assembly relative to a plane of a mounting interface;

[0020] Figure 5A yes Figure 3 a rear side view of a lead frame assembly;

[0021] Figure 5B yes Figure 3 a rear side view of the housing excluding the lead frame assembly;

[0022] Fig. 6A yes Figure 2A Front view of the stackable I / O connector;

[0023] Figure 6B yes Figure 2A A front view of a lead frame assembly of a stacked I / O connector, excluding a housing;

[0024] Figure 7 yes Figure 2A A side view of a lead frame assembly of a stacked I / O connector, excluding the housing;

[0025] Figure 8 yes Figure 7 a side view of a lead frame assembly with an outer upper lead frame assembly and an outer lower lead frame assembly removed;

[0026] Fig.9A is a perspective view of a member at least partially in electrical communication with a protrusion configured to project toward a ground conductor of an outer upper lead frame assembly;

[0027] Fig. 9B is a perspective view of two members at least partially in electrical communication with a protrusion configured to protrude toward a ground conductor of an outer upper lead frame assembly and an inner upper lead frame assembly;

[0028] Fig. 9C yes Figure 7 a perspective view of an inner upper conductive element of a lead frame assembly;

[0029] Fig. 10A is a front right perspective view of an exemplary embodiment of a stacked 2x1 cage;

[0030] A1156.70744CN01

[0031] Fig. 10B yes Fig. 10A Rear right perspective view of the stacked 2x1 cage;

[0032] Fig. 10C yes Fig. 10A Rear bottom right perspective view of the stacked 2x1 cage;

[0033] Fig.11A is a front right side perspective view of an exemplary embodiment of a coupled 2x4 cage; and

[0034] Fig. 11B yes Fig.11A Rear right side perspective view of the joined 2x4 cage. DETAILED DESCRIPTION

[0035] The present disclosure relates to an electronic connection system that can comply with the OSFP specification. The inventors have recognized and appreciated that the I / O design provides thermal and electrical characteristics that support high-speed transceiver operation, including at data rates greater than 110 Gbps, even in a stacked configuration. The inventors have recognized and appreciated that increased density I / O connections may require improved heat dissipation when using I / O connectors that are traditionally located in the air flow path of the cooling transceiver.

[0036] Increased density may result from transceivers that handle more signals in the same space, such as may result from transceivers that conform to the OSFP specification. Additionally, increased density may result from "stacked" connectors, which result in transceivers being stacked on top of each other with little space between them. Even for stacked connectors, the design of the connector may provide improved heat dissipation.

[0037] These techniques may require that the connector be formed with a mesh housing on all or part of the outer surface of the housing. For example, the rear wall may be open and may be open on most (e.g., at least 50%, at least 60%, at least 75%, or at least 80%) of the mating surface, top, and side portions other than the support member. The lead assembly inserted into the housing may similarly be formed with openings to allow air to flow through the connector. The air can flow from the front to the rear with relatively low resistance to be consistent with the flow of cooling air in many electronic devices.

[0038] Additionally, metallic members or at least partially conductive members may be attached to the leads to improve signal integrity. These members may be positioned where they provide suitable improvements to signal integrity to support high data rates without providing unacceptable resistance to airflow.

[0039] In some embodiments, the at least partially conductive member includes a protrusion that is electrically and mechanically coupled to a selected conductive element in the connector. For example, the selected conductive element can be a ground conductor, and the electrical and mechanical coupling can be achieved by welding the metal member and / or the metal portion of the member including the metal portion and the lossy portion to the ground conductor. The connection of such a member can increase signal integrity at higher frequencies, enabling the connector to carry high-speed signals.

[0040] For example, such connectors can be used in devices such as switches, routers, servers, and other high-performance electronic devices. Figure 1A As shown, the electronic system 100 may include a housing 140 including a panel 142 having at least one opening 144 therethrough.

[0041] A printed circuit board 130 may also be included within the housing 140. The electronic system 100 may also include a cage 110. The cage 110 may be mounted to the printed circuit board 130 and may surround a connector 200 ( FIG. 2 ) mounted to the printed circuit board 130. The electronic system 100 may also include a fan 150. For example, the fan 150 may exhaust air from the housing, thereby causing an airflow 180.

[0042] In some embodiments, cage 110 can be configured to provide shielding from electromagnetic interference. Cage 110 can be formed of any suitable metal or other conductive material and grounded to shield EMI using techniques known to those skilled in the art. Cage 110 can be formed of sheet metal bent into a suitable shape. However, some or all of the components of the cage can be made of other materials, such as die cast metal.

[0043] exist Figure 1A In the example shown, the cage 110 can include a first channel 112. The cage 110 can include a second channel 114. The cage 110 can include a third channel 116. In the illustrated embodiment, the second channel 114 is located between the first channel 112 and the third channel 116. The first channel 112 can be adjacent to the printed circuit board 130. In this example, the first channel 112 and the third channel 116 can each be configured to receive a transceiver, each of which can mate with the connector 200.

[0044] The cage 110 may be defined by a conductive top wall, a conductive bottom wall, and / or conductive side walls. These walls and / or partitions inside the cage 110 may form the top and bottom walls of the channels. One or more wall pieces may be combined to provide shielding around each channel and a transceiver that may be inserted into the channel.

[0045] According to some embodiments, fan 150 can be positioned to flow air over or through cage 110. For example, fan 150 can be positioned to exhaust air from housing 140. Figure 1A The fan 150 is schematically shown adjacent to a wall of the housing 140, but the fan 150 may be positioned in any suitable location. For example, the fan 150 may be positioned within the housing 140. In some embodiments, such as in a rack-mounted electronic device, the I / O connectors may be exposed at the front surface of the housing, and one or more fans exhaust air from the opposite rear surface of the housing. However, it should be understood that other suitable locations may create a pressure drop that causes air to flow through the components within the electronic housing.

[0046] In the illustrated embodiment, the second channel 114 has a face with a honeycomb pattern of holes that emerges within the opening 144. The holes allow air to flow into the second channel 114 so that the air flowing through the cage 110 can evacuate heat generated by the transceivers within the channels 112 and 116.

[0047] In some embodiments, the cage may enable airflow to cool a transceiver mated with the stacked I / O connector without an intermediate channel, such as the second channel 114 . Figure 1B Such a cage 110B is shown having channels 112B and 116B, but no intermediate channels. In this example, cage 110B includes holes 160 in the vertical side walls of the cage and holes 162 in the top surface of the cage. Similar holes may be included in the rear surface 164, but such holes are located in the rear surface 164. Figure 1B It is not visible.

[0048] exist Figure 1B In the example of , channel 112B and channel 116B are sized to receive a transceiver with an integrated heat sink 172 . Figure 1C An exemplary transceiver 170 is shown in FIG. The transceiver 170 includes a paddle card 174 that is configured to be inserted into a slot of a receptacle connector within a cage.

[0049] In the illustrated embodiment, the heat sink 172 includes a plurality of fins extending vertically and parallel to the length of the channel into which it is inserted. Airflow along the elongated dimension of the channel can flow through and along the fins in the airflow direction 180, thereby removing heat. In the illustrated embodiment, the heat sink 172 includes a cover plate, but in some embodiments, such a cover plate may be absent.

[0050] According to some embodiments, the connector 200 mounted at the rear of the cage 110B can also be configured to enable air to flow through the cage 110B with low resistance. The lower flow resistance can, in turn, increase the heat dissipation capabilities of the system and enable the system to operate with high-capacity transceivers such as transceivers operating according to the OSFP specification, or other transceivers capable of operating at data rates in excess of 110 Gbps, and in some embodiments at frequencies in excess of 110 GHz, for example.

[0051] Figure 2A and Figure 2B 1. A connector 200 is shown. In this example, the connector 200 is a stacked surface mount connector that is configured to mate with two transceivers that are inserted into two channels (e.g., channel 112 and channel 116) stacked on top of each other (one above the other). As shown, the connector 200 can have a housing and / or plastic portion on the die that is hollowed out to improve airflow and thermal performance. For example, the connector 200 has a mesh housing 210 that provides suitable support for conductive elements that mate with a transceiver inserted into the connector 200, but has a large number of open portions so that the cage (e.g., surrounding the connector 200) can be used to connect the conductive elements to the transceiver. Figure 1BThe air flowing through the cage 110B) encounters very little resistance.

[0052] The housing 210 can be molded from an insulating material such as plastic, nylon, PCP, etc. Glass fiber or other fillers may be included in the material to establish the desired dielectric properties and / or enhance the strength of the insulating material. In this example, the housing 210 supports slots 232A and 232B at the mating surface 230. Each slot includes a wall defining a slot. In this example, the slot is configured to receive the mating portion of an OSFP transceiver. However, each slot can be configured to mate with other types of components.

[0053] The connector 200 is shown here as a right-angle connector that is configured as a stacked surface mount (SMT) I / O connector. The mounting surface 212 is perpendicular to the mating surface 230. The mounting surface 212 includes contact tails that pass through the conductive elements of the connector 200. In this example, the contact tails are surface mount contact tails. To facilitate surface mount attachment, the mounting interface 212 may also include a clamp 214. The clamp 214 may be embedded in a section 218 of the connector side wall so that the press-fit portion extends through the mounting surface 212, so that the clamp can be inserted into a printed circuit board (e.g., the printed circuit board 130 of Figure 1) on which the connector 200 is mounted to position and hold the connector 200 for surface mount soldering.

[0054] A1156.70744CN01

[0055] Figure 3 200. As shown, the housing 210 includes sidewalls 320A and 320B that define a chamber 360. In this example, the housing 210 has a substantially open rear portion so that air can easily flow out of the chamber 362 from the rear portion of the connector 200.

[0056] Each side wall above the section 218 adjacent the mounting surface has a mesh structure to provide one or more openings 322 so that air can flow through the side walls 320A and 320B. The portion of the side wall above the section 218 may be open, for example, by more than 50%.

[0057] In some embodiments, opening 322 may be aligned with an opening in a cage that may surround connector 200. Alternatively or additionally, sidewall 320A and / or sidewall 320B may be set back from the widest dimension of connector 200 so that a cage having vertical walls that abut the widest point of the connector separates the air passage from sidewall 320A and / or sidewall 320B. Figure 3In the example of FIG. 3 , an indentation 324 is shown. In this example, the indentation 324 is formed at the bottom of the channel between the sidewalls 320A and 320B and the vertical wall of the cage. Air can flow through the openings 322 and through these channels around the lead subassemblies 310A and 310B.

[0058] By inserting the upper lead subassembly 310A and the lower lead subassembly 310B into the chamber 360, the conductive element is integrated into the connector 200. In this example, the upper lead subassembly 310A includes a conductive element inserted into the slot portion 232A. The lower lead subassembly 310B includes a conductive element inserted into the slot portion 232B. In the illustrated example, the slot in each slot portion is used as a mating interface with the plug. The slot has opposing surfaces, and the mating contact portion of the conductive element is exposed through these surfaces so that it can establish contact with the pad or other contact surface in the insertion slot of the plug.

[0059] Each of the lead subassemblies can be formed by a plurality of lead assemblies. Here, two lead assemblies are pressed together to form a lead subassembly. The lead subassemblies can be fixed to each other before being inserted into the housing 210, or in some embodiments, can be kept close to each other when inserted into the housing 210. In this example, the upper outer lead assembly 312 and the upper inner lead assembly 314 together form the lead subassembly 310A. The lower outer lead assembly 316 and the lower inner lead assembly 318 together form the lead subassembly 310B.

[0060] Housing 210 can include a top surface having a central member 350. Central member 350 can span only a portion of the width of the top surface, leaving openings 352 on either side of central member 350. Openings 352 can enable air to flow from the interior of chamber 360 through the top surface to the exterior of the housing. Central member 350 can provide rigidity and / or mechanical strength to housing 210. In addition, the shape of central member 350 can be designed to engage with complementary features on lead subassembly 310A. When lead subassembly 310A is inserted into housing 210, tabs 340 on lead subassembly 310A can engage with central member 350.

[0061] The top surface may have a plurality of grooves 354. Here, the grooves extend parallel to the side walls 320A and 320B. Such grooves may provide air flow between the housing and the top wall of the cage surrounding the connector 200.

[0062] Through such channels, air can flow through the cage and around the connector 200 with low resistance. For example, such air flow can follow a path through a channel (e.g., channel 112B or channel 116B) and out the top or back of the cage. Figure 3As can be seen, the grooves 354 are interrupted by openings 352. Thus, cooling air can follow one or more paths through the connector. For example, air can enter the passages between the top surface of the connector 200 and the top of the cage surrounding the connector 200 by flowing into the grooves 354 adjacent to the mating face of the connector 200. Alternatively or additionally, air can enter these passages by flowing through the openings 530 in the mating face and then flowing through the openings 352 in the top surface of the connector 200.

[0063] Platform 330 can span from sidewall 320A across chamber 360 to sidewall 320B. Platform 330 is positioned adjacent to slot 232B and between slot 232B and slot 232A. Platform 330 can provide rigidity and / or mechanical strength to housing 210. Similar to central member 350, platform 330 can be shaped to engage with complementary features on lead subassembly 310B. When lead subassembly 310B is inserted into housing 210, tabs (at Figure 3 (not visible in the figure) can be engaged with platform 330.

[0064] Further rigidity and / or mechanical strength may be provided to the housing 210 by a support member 332 extending from a central portion of the platform 330. The support member 332 may have openings therethrough to allow air to flow from the mating face 230 through the support member 332 into the chamber 360.

[0065] Figure 4 Further details of connector 200 are shown. Figure 4 In FIG. 3 , the middle portion of the lead subassembly 310A can be seen. The middle portion is inclined at an angle A relative to the mounting surface 212. In contrast, Figure 3 As shown, the middle portion of lead subassembly 310B is parallel to mounting surface 212. Therefore, the middle portion of lead subassembly 310A can be tilted at angle A relative to the middle portion of lead subassembly 310B. Figure 4 As can be seen, lead subassembly 310A aligns opposite ends of the lead subassembly with openings 322. Air flowing through connector 200 encounters less resistance than a connector having solid sidewalls or without angled lead subassemblies because air can flow into openings 322 and around the ends of lead subassembly 310A.

[0066] Figure 5A and Figure 5B The components of the connector 200 are illustrated from the rear. In this view, it can be seen that the components of the connector 200 are configured to allow air to flow through the connector 200 from the front to the rear. Figure 5A Lead subassembly 310A and lead subassembly 310B are shown, with lead assembly 312 visible in this view.

[0067] The lead assembly 312 includes a plurality of conductive elements 510 held in one or more insulating portions 520. The lead assembly 312 may be formed, for example, by insert molding the insulating portion 520 around a lead frame. The individual conductive elements 510 may be held in the lead frame A1156.70744CN01 using tie rods (e.g., 930 of FIG. 9 ).

[0068] The tie rods can be cut off after the insert molding operation. The conductive elements 510 are held in a row orientation, spanning the chamber 360 from the side wall 320A to the opposite side wall 320B. Since adjacent conductive elements 510 in a row are physically isolated from each other to provide electrical isolation between the conductive elements, there are spaces between the conductive elements through which air can flow even when the lead subassemblies 310A and 310B are inserted into the chamber 360.

[0069] Lead assembly 314 , lead assembly 316 , and lead assembly 318 may have similar structures.

[0070] Figure 5B The back side of the mating surface 230 of the connector 200 can be seen in FIG. It can be seen that most of the mating surface 230 between the groove portion 232A and the groove portion 232B is open, forming a hole 530. Therefore, air can flow through the mating surface 230 into the chamber 360. As described above in conjunction with Figure 1A and Figure 1B As described, cooling air can be drawn into cage 110 or cage 110B to cool a transceiver inserted into the cage. Compared to conventional designs where stacked connectors at the rear of the cage block airflow from exiting the cage, connector 200 can provide substantially lower resistance to airflow for cooling a transceiver inserted into the cage. Aperture 530 can be aligned with a channel of the cage through which air is to flow, such as second channel 114 ( FIG. 1 ). Thus, air flowing through the cage to cool the transceiver can enter chamber 360 through mating face 230.

[0071] Because the back, sides, and top of the insulating housing 210 also include a large number of openings, air flowing into the chamber 360 can easily exit the chamber 360 through any or all of these openings to the outside of the housing so that it can be exhausted from the system or otherwise processed to dissipate heat.

[0072] Fig. 6A The connector 200 is shown from the front, illustrating that a relatively large proportion of the mating interface between the slots is open. Figure 6B Lead subassembly 310A and lead subassembly 310B are shown.

[0073] Figure 7Shown are further structural details of exemplary lead subassembly 310A and lead subassembly 310B.Each in the lead subassembly is formed by two lead assemblies, and each lead assembly has a row of conductive elements held in an insulating member.Lead assembly 312 has a row of conductive elements held in insulating portions 722A, 724A and 726A.Contact tails can be exposed at one end of the lead assembly, and mating portion 710 can be exposed at the other end.The insulating portion has a frame-like configuration, thereby providing support around its periphery, and has an open area that will not block the space between the conductive elements, so that air can flow through the lead assembly in some embodiments.

[0074] One or more of insulating portions 722A, 724A, and 726A may include features that engage with insulating housing 210. For example, insulating portion 726A may have features that engage with complementary features in or near slot 232A. Insulating portion 722A may have features that engage housing 210 at or near segment 218.

[0075] Respective insulating portions 722B, 724B, and 726B can hold together the conductive elements that form lead assembly 314. Similarly, insulating portions can hold the conductive elements in wire assemblies 316 and 318 in a row.

[0076] Figure 8 It is shown that each of the lead subassemblies can include at least partially conductive components. These components can be positioned to interconnect selected conductive elements in the lead assemblies. For example, one or more of the lead subassemblies can have one or more welded metal shorting bars to improve the electrical performance of the connector. Figure 8 Lead subassembly 310A is shown without lead assembly 312 so that lead assembly 314 can be seen along with members 810A, 810B, 810C, 810D positioned to establish connections between selected conductive elements in lead assembly 312 .

[0077] Components 810A, 810B, 810C, 810D are positioned to establish connection with the conductive elements of lead assembly at the position along its length, and it effectively improves the integrity of high-speed signals in lead assembly 312 at this position. For example, the number and spacing of conductive elements can be selected so that the maximum spacing between conductive elements is less than half of the wavelength of the highest frequency in the design operation range of connector. Conductive elements can also be positioned to not block the air flow through wire assembly. The positioning of these parts can be a compromise between satisfying the target of improving signal integrity and not blocking airflow. For example, these components can be positioned to be spaced apart unevenly along the length of conductive elements to avoid, for example, alignment of components in the middle portion with opening 530. Figure 8Example locations that meet these criteria are shown in .

[0078] Likewise, lead subassembly 318 is shown without lead assembly 316 so that at least partially conductive members (not numbered) positioned to make contact with selected conductive elements in lead assembly 316 can be seen. In contrast to four members 810A, 810B, 810C, 810D that contact conductive members along the length of conductive elements in lead assembly 312, two such members are configured to make contact with conductive elements of lead assembly 316. Similarly, at least partially conductive members are positioned to make contact with selected conductive elements of lead assembly 314 and lead assembly 318.

[0079] In some connectors, the configuration of the conductive elements in each row of the rows of conductive elements in the connector can be the same. In this configuration, the components that contact a selected number of conductive elements in a row of conductive elements can have the same configuration. For example, the conductive elements in a row can be configured to be arranged as a repeated signal-signal-ground (SSG), and each component can be configured to contact grounding. In this configuration, the component can have a protrusion aligned with the ground conductor. These components can be attached to the lead assembly so that the protrusion contacts the ground conductor or extends toward the ground conductor and approaches the ground conductor. In the illustrated embodiment, the protrusion can be welded to the ground conductor.

[0080] Fig.9A An exemplary member 810C is shown. In this example, the protrusion 912 is U-shaped. The protrusions are held together by a body, which is here formed as a rod 910. A member having the configuration shown is A1156.70744CN01

[0081] The piece may be formed from sheet metal that is stamped and then molded.

[0082] Component 810C is shown oriented to attach to conductive elements in lead assembly 312. It can be seen that each of the lead assemblies holds a row of conductive elements, and the body of the component is elongated in the direction of the row. This configuration enables the body to be electrically connected to multiple conductive elements in the row. Fig. 9C Conductive elements are shown before being insert molded into lead assembly 312. In this example, there are two groups of conductive elements, each group having a first type of conductive element and a second type of conductive element. Each third conductive element can be of the second type and can have a wide portion 940 that is wider than the other portions of the second type conductive element and wider than the first type conductive element. The second type of conductive element can be a ground conductor, while the first type can be used as a signal conductor. Protrusion 912 can be soldered to wide portion 940.

[0083] The weld can provide a low inductance connection between the ground conductors, which can increase the frequency at which the ground system resonates within the connector, thereby enabling the connector to operate at high frequencies. A relatively wide and long weld joint can be formed between the protrusion 912 and the ground conductor, which facilitates a low inductance connection. For example, the joint can be greater than 0.4 mm long, such as between 0.4 mm and 1 mm long, and greater than 0.2 mm wide, such as between 0.2 mm and 0.4 mm wide.

[0084] Low inductance can also be provided by relatively wide conductive paths between adjacent ground conductors. In the illustrated embodiment, adjacent ground conductors are coupled via rod 910 and side bars 941A and 914B. The structures forming the conductive paths between the connections adjacent to the ground conductors can collectively have an average width in a direction parallel to the direction in which the ground conductors extend, between 1 mm and 5 mm, such as between 1.5 mm and 3.5 mm, or in some embodiments between 2 mm and 3 mm.

[0085] In addition, the spacing between the rod 910 and the signal conductor can be set by the height of the protrusion 912, and the height of the protrusion can be stable. Therefore, the impedance along the signal conductor does not change during operation, avoiding the degradation of signal integrity that may be caused by impedance changes.

[0086] In addition, reliable connections can be established in limited spaces without the need for gold or other precious metal coatings, such as those that can be used with ground rods connected via spring fingers. If the connection to the ground conductor is established through spring fingers, it is necessary to include a clamp or clamping structure to hold lead assembly 312 and lead assembly 314 or lead assembly 316 and lead assembly 218 together. In embodiments where the connection between the ground conductors is established by welding, the clamp or clamping feature can be omitted, thereby saving space.

[0087] Furthermore, avoiding the use of spring fingers eliminates the need to shape the connection points to produce the required spring forces, which may result in long and / or narrow interconnections, thereby undesirably increasing inductance.

[0088] Fig. 9B A similar member 820C is shown connected to member 810C. Member 820C can be connected to member A1156.70744CN01

[0089] Component 810C is identical to component 810C except that it is oriented to connect to conductive elements in lead assembly 314.

[0090] Using a connector having some or all of the features described above for connector 200 can enable a system (e.g., electronic system 100) to operate according to a desired method. Electronic system 100 can be disposed in an ambient environment. Electronic system 100 can include a housing 140 and a cage 110 within housing 140, cage 110 including a stacked first channel 112, a second channel 114, and a third channel 116. However, it should be understood that the cage can be configured to have more or fewer channels. For example, in a stacked connector assembly, there can be two channels, such as channel 112B and channel 116B ( Figure 1B ), each channel is designed as a receive transceiver, with no intermediate channels such as channel 114.

[0091] The method according to the present embodiment includes sending and / or receiving an optical signal with a transceiver disposed in the first channel 112, and / or sending and / or receiving an optical signal with a transceiver disposed in the third channel 116, in each case, the data rate exceeds 110Gbps, for example 112Gbps or greater. In some embodiments, the transceiver in each of the first channel 112 and the third channel 116 may consume at least 1W, less than 15W, or in some embodiments, between 1W and 15W. In some embodiments, the transceiver may consume 1.5W, 3.5W, 7W, 8W, 10W, 12W, 14W or more than 14W. This power consumption is consistent with an OSFP transceiver. The transceiver may have an integrated heat sink so that the heat generated by the transceiver is evacuated by air flowing through the channel receiving the transceiver. The connector as described above can contribute to the airflow to provide suitable cooling.

[0092] The method according to this embodiment includes flowing air through the cage with a fan 150 disposed in the housing 140. The fan 150 can operate at a static pressure of at least 0.8 inches of water (IW), less than 1.5 IW, or between 0.8 IW and 1.5 IW. Heat is dissipated from the transceivers in the first channel 112 and / or the third channel 116 so that the temperature rise of both transceivers relative to the off state of the transceivers is less than 25 degrees Celsius. With this configuration, the heat dissipated from the cage can be sufficient so that this temperature rise can be achieved even if the electronic housing is in an ambient environment of 25 degrees Celsius. Even without an intermediate channel, such as the second channel 114, which can be omitted in some embodiments, sufficient cooling can be achieved to provide a temperature rise at or below this level.

[0093] In an exemplary embodiment, the system is set up in an environment of 25 degrees Celsius. The cage is formed of sheet metal bent into a suitable shape. The cage includes two channels stacked, each channel configured to receive an OSFP transceiver. Each transceiver can consume 12 watts of power. A fan is set within the housing and is configured to operate at a static pressure of 1.0IW. The airflow through the cage with the connector 200 in the cage is sufficient to cool the transceivers so that the temperature rise of the transceivers in the first channel relative to the off state of the transceiver is 25 degrees Celsius or less. The temperature rise of the transceivers in the top channel relative to the off state of the transceiver is 25 degrees Celsius or less. A comparable temperature rise can be observed in the lower channel. A1156.70744CN01

[0094] It should be understood that various aspects of the present disclosure are described herein with reference to certain illustrative embodiments and accompanying drawings. The exemplary embodiments described herein are not necessarily intended to illustrate all aspects of the present disclosure, but are used to describe some exemplary embodiments. Therefore, aspects of the present disclosure are not intended to be interpreted narrowly in view of the illustrative embodiments. In addition, it should be understood that various aspects of the present disclosure can be used alone or in any suitable combination with other aspects of the present disclosure.

[0095] For example, Fig. 10A , Fig. 10B and Fig. 10C An alternative embodiment of a stacked cage 1010 is shown having channels 1012 and 1016 and an intermediate channel 1014. In this example, the cage 1010 includes holes 1060 in the vertical side walls of the cage and holes 1062 in the top surface of the cage. Similar holes may be included in the back surface 1064.

[0096] Fig. 10C Cage 1010 is shown viewed from its mounting surface. In this view, opening 1080 in the mounting surface is visible. In some embodiments, connector 200 may be surface mounted and soldered to, for example, printed circuit board 130 ( Figure 1A ) on a pad on the surface of a printed circuit board. Cage 1010 can be placed on connector 200, where connector 200 fits within opening 1080. Press-fit tails 1086 extending from the edge of the side wall of cage 1010 can be pressed into the ground via of the printed circuit board, both securing cage 1010 and grounding it.

[0097] In some embodiments, spring fingers such as spring fingers 1082 and spring fingers 1084 may be used to provide less interference. These spring fingers may be cut from the same sheet of metal used to form other structures of cage 1010, or may be formed separately and attached to cage 1010. In this example, spring fingers 1082 and spring fingers 1084 define the edges of opening 1080. In this example, they define a front edge and an opposite rear edge of opening 1080. The printed circuit board to which cage 1010 is mounted may have elongated surface pads that are connected to ground structures within the printed circuit board and are configured as strips that align with spring fingers 1082 and 1084. Thus, when cage 1010 is pressed onto the circuit board, additional grounding is provided around the contact tails of the conductive elements of connector 200. Thus, the printed circuit board to which connector 200 is mounted may include a connector footprint having multiple rows of pads, each row of pads being configured to receive a contact tail from one of the lead assemblies of connector 200. The ground strips may be parallel to the rows of pads and located on either or both sides of the rows of pads.

[0098] Fig.11A and Fig. 11B Another embodiment of a cage that can be used with connector 200 is shown. In this example, cage 1110 is a 4x2 configuration of a linked cage. Cage 1110 has four sections, each of which is generally configured as cage 1010, with a channel, a top hole 1162, and a hole in the rear surface 1164. Connector 200 can be positioned within each section. The features described herein can provide multiple airflow paths through the channels of the cage where the transceiver can be mounted and then exit the cage. These airflow paths can include paths that allow air to flow partially around the connector and out of the holes on the top of the cage or flow around the connector and out of the holes at the rear of the cage.

[0099] In a stacked configuration, the sides of some or all of the segments may be blocked by adjacent segments. Thus, in the illustrated embodiment, the airflow path may not include a path to exit the cage through a side hole such as side hole 1060. Nevertheless, adequate cooling may still be provided because air may flow around the connector through a channel between the side wall of the connector housing and the vertical wall of the cage, or may partially pass through and partially flow around the connector, for example, by flowing through an opening 530 in the front of the housing and out of the housing through a side opening 322 into a channel between the housing and the cage, or around a lead assembly and out of the back of the connector. Thus, a connector configured as described herein having a housing with multiple openings and / or multiple channels disposed between the housing and the cage may achieve effective cooling of a transceiver mated with the connector.

[0100] As another example of a variation, members 810A, 810B, 810C, 810D are described as being at least partially conductive. In the illustrated embodiment, these members are conductive and made of metal. In other embodiments, these members may be lossy materials, or include lossy materials, such that these members are partially conductive. In some embodiments, lossy materials may be used instead of or in addition to metal to form members such as members 810A, 810B, 810C, and 810D. For example, lossy materials, such as lossy plastics, may be molded onto metal members or otherwise adhered to metal members. Alternatively, the lossy material may be mechanically fixed to the metal member, such as by pressing a barb on the metal member into the lossy material.

[0101] Materials that are electrically conductive but somewhat lossy, or that absorb electromagnetic energy in the frequency range of interest through another physical mechanism, are generally referred to herein as "lossy" materials. Electrically lossy materials can be formed from lossy dielectric and / or poorly conductive and / or lossy magnetic materials. Magnetic lossy materials can be formed from, for example, materials that are traditionally considered to be ferromagnetic materials, such as those that have a magnetic loss tangent greater than about 0.05 in the frequency range of interest. The "magnetic loss tangent" is the ratio of the imaginary part to the real part of the complex dielectric constant of a material. Actual lossy magnetic materials or mixtures containing lossy magnetic materials may also exhibit useful amounts of dielectric loss or conductive loss effects in portions of the frequency range of interest.

[0102] Electrically lossy materials can be formed from materials that are traditionally considered to be dielectric materials, such as those that have an electrical loss tangent greater than about 0.05 over the frequency range of interest. "Electrical loss tangent" is the ratio of the imaginary part to the real part of the complex dielectric constant of a material. Electrically lossy materials can also be formed from materials that are generally considered to be conductors, but are relatively poor conductors over the frequency range of interest, contain conductive particles or regions that are not well dispersed so that they do not provide high conductivity, or are otherwise prepared to have such properties that the loss tangent is greater than about 0.05 over the frequency range of interest. A1156.70744CN01

[0103] In the surrounding area, the bulk conductivity is relatively poor compared to good conductors such as copper.

[0104] Electrically lossy materials typically have a bulk conductivity of about 1 siemens / meter to about 10,000 siemens / meter, and preferably have a bulk conductivity of about 1 siemens / meter to about 5,000 siemens / meter. In some embodiments, materials with a bulk conductivity between about 10 siemens / meter and about 200 siemens / meter may be used. As a specific example, a material with a conductivity of about 50 siemens / meter may be used. However, it should be understood that the conductivity of the material can be selected empirically or by electrical simulation using known simulation tools to determine a suitable conductivity that provides appropriately low crosstalk and appropriately low signal path attenuation or insertion loss.

[0105] The electrically lossy material may be a partially conductive material, such as those having a surface resistivity between 1 ohm / m2 and 100,000 ohm / m2. In some embodiments, the electrically lossy material has a surface resistivity between 10 ohm / m2 and 1000 ohm / m2. As a specific example, the material may have a surface resistivity between 20 ohm / m2 and 80 ohm / m2.

[0106] In some examples, the electrically lossy material is formed by adding a filler containing conductive particles to a binder. In such examples, the lossy member can be formed by molding or otherwise forming the binder and the filler into a desired shape. Examples of conductive particles that can be used as fillers to form electrically lossy materials include carbon or graphite formed into fibers, flakes, nanoparticles, or other types of particles. Metals in the form of powders, flakes, fibers, or other particles can also be used to provide suitable electrically lossy properties. Alternatively, a combination of fillers can be used. For example, metal-plated carbon particles can be used. Silver and nickel are suitable metals for plating fibers. Coated particles can be used alone or in combination with other fillers such as carbon flakes. The bonding agent or matrix can be any material that is placed, cured, or can be used to position the filler. In some examples, the bonding agent can be a thermoplastic material that is traditionally used to manufacture electrical connectors, which is conducive to molding the electrically lossy material into a desired shape and position as part of the manufacture of electrical connectors. Examples of such materials include liquid crystal polymers (LCP) and nylon. However, many alternative forms of bonding agent materials can be used. Curing materials such as epoxy resins can act as bonding agents. Alternatively, materials such as thermosetting resins or adhesives may be used.

[0107] Likewise, the above-described binder material can be used to obtain an electrically lossy material by forming a binder around a conductive particle filler, but the technology described in this application is not limited thereto. For example, the conductive particles can be impregnated into the formed matrix material, or can be coated onto the formed matrix material, such as by applying a conductive coating to a plastic part or a metal part. As used herein, the term "binder" includes a material that encapsulates a filler, is impregnated with a filler, or otherwise acts as a substrate to hold a filler.

[0108] Preferably, these fillers are present in sufficient volume percentage to form a conductive path from particle to particle. For example, when metal fibers are used, the fibers may be present in a volume percentage of about 3% to 40%. The amount of filler may affect the conductive properties of the material.

[0109] Filling materials are commercially available, such as Celanese Corporation's Materials sold under the trademark TECHFILM, which may be filled with carbon fibers or stainless steel filaments. Lossy materials may also be used, such as lossy conductive carbon filled with a viscous preform, such as materials sold by Techfilm, Inc. of Bill Marica, Massachusetts, USA. This preform may include an epoxy resin binder filled with carbon fibers and / or other carbon particles. The binder surrounds the carbon particles to serve as a reinforcing structure for the preform. Such a preform may be inserted into a connector wafer to form all or part of a housing. In some embodiments, the preform may be adhered by an adhesive in the preform, which may be cured during a heat treatment process. In some embodiments, the adhesive may take the form of a separate conductive adhesive layer or a non-conductive adhesive layer. In some embodiments, the adhesive in the preform may be used alternatively or in addition to fix one or more conductive elements such as foil to the lossy material.

[0110] Various forms of reinforcing fibers (woven or non-woven form) can be used coated or uncoated. Non-woven carbon fibers are one suitable material. Other suitable materials may be used, such as custom blends sold by RTP Company, as the present application is not limited in this regard.

[0111] In some embodiments, the lossy portion can be manufactured by stamping a preform or sheet of lossy material. For example, the lossy portion can be formed by stamping a preform as described above with a mold having an appropriate pattern. However, other materials can be used instead of or in addition to such preforms. For example, a sheet of ferromagnetic material can be used.

[0112] However, the lossy portion may be formed in other ways. In some embodiments, the lossy portion may be formed by interleaving layers of lossy and conductive materials such as metal foil. The layers may be firmly attached to each other, such as by using an epoxy or other adhesive, or may be held together in any other suitable manner. The layers may have the desired shape before being secured to each other, or may be stamped or otherwise formed after they are held together. As a further alternative, the lossy portion may be formed by coating a plastic or other insulating material with a lossy coating such as a diffusion metal coating.

[0113] In yet other embodiments, lossy materials can be integrated with lossy components 810A, 810B, 810C, 810D attached to lead assembly 312 as shown, and other similar components attached to other lead assemblies by coating the lossy material on the components. The coating can be applied as an adhesive. The adhesive can be used as a binder and can be filled with particles that make the adhesive lossy. Alternatively, other binders can also be used alternatively or additionally. Similarly, the lossy material can be applied as an ink, or can be used as a preform adhered to a metal component. Alternatively, the lossy structure can be mechanically attached to the metal component, such as by a snap fit, an interference fit, or other suitable type of mechanical connection. The lossy structure can be formed separately, such as by molding, and then mechanically attached to the metal component.

[0114] For purposes of this patent application and any patents that issue thereon, the indefinite articles "a" and "an" as used in the specification and claims, unless expressly indicated to the contrary, are to be understood to mean "at least one". The phrase "and / or" as used herein in the specification and claims is to be understood to mean "one or both" of the elements so combined, i.e., elements that are present in combination in some cases and separated in other cases. Multiple elements listed with "and / or" should be interpreted in the same manner, i.e., "one or more" of the elements so combined. In addition to the elements specifically identified by the "and / or" clause, other elements may optionally be present, whether related or unrelated to those specifically identified elements.

[0115] The use of “including,” “comprising,” “having,” “containing,” “involving,” and / or variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0116] The above description of various embodiments is intended to illustrate these embodiments only, and other embodiments, modifications, and equivalents are within the scope of the invention as described in the claims of this application.

[0117] After describing several embodiments in this way, it should be understood that those skilled in the art can easily make various changes, modifications and improvements. Such changes, modifications and improvements are intended to fall within the spirit and scope of the present invention. Therefore, the foregoing description and accompanying drawings are only examples.

[0118] Various changes may be made to the illustrative structures shown and described herein. As a specific example of possible variations, an embodiment is described in which the connection between the transceiver and the connector is an electrical connection. An embodiment in which the connection is optical is possible.

[0119] As another example, the connector is shown as having a meshed connector housing. The illustrated housing has openings on the front, back, both sides, and top. This configuration provides multiple airflow paths through the connector, such as through the front of the connector and out of the top, through the front and out of the two sides, or through the face and lead subassembly and out of the back. The connector can be implemented so that there is a channel for airflow along one or more of these paths.

[0120] The resistance to airflow along each path may depend on the other components of the system in which the connector is used. Figure 3 ) has airflow holes aligned with the top, sides, and back of the connector in the cage so that if the connector is configured with the airflow channels described herein, air can flow along all of these paths. In other embodiments, for example, the cage may have no openings in the top and no airflow out of the top of the connector. In other embodiments, the connector may only be implemented with a subset of the airflow channels of A1156.70744CN01 described herein. For example, there may be openings on only one side of the connector housing.

[0121] As another example of variation, in some embodiments, the contact tails are exemplified as surface mount components. However, other configurations may also be used, such as a press fit "eye of the needle" flex portion designed to fit within a through hole of a printed circuit board, solderable pins, etc., as the various aspects of the present disclosure are not limited to the use of any particular mechanism for attaching the connector to the printed circuit board.

[0122] In addition, the connectors described herein are configured to cooperate with transceivers according to the OSFP standard. The techniques described herein can be used for connectors configured to operate with other standards (e.g., QSFP-DD or other SFP standards), or for other I / O connectors, even if not specifically configured to operate with the SFP standard. Although stacked connectors are exemplified, one or more techniques may also be applied to single-port I / O connectors. For example, in a single-port connector, a conductive member may be welded to a ground conductor as described herein. In addition, one or more techniques described herein may be applied to connectors configured other than I / O connectors, such as backplane connectors.

[0123] It should also be understood that, unless explicitly stated to the contrary, in any method claimed herein that includes one or more steps or acts, the order of the method steps or acts is not necessarily limited to the order in which the method steps or acts are recited.

Claims

1. A stacking connector, comprising: A housing, the housing comprising: a first side wall and a second side wall opposite to the first side wall; a mating surface extending between the first side wall and the second side wall, the mating surface comprising a first groove and a second groove; a mounting surface, the mounting surface being perpendicular to the mating surface and extending between the first side wall and the second side wall; a top surface opposite the mounting surface and extending between the first side wall and the second side wall; and a plurality of conductive elements, each of the plurality of conductive elements comprising a mating contact portion, a contact tail portion, and an intermediate portion connecting the mating contact portion and the contact tail portion, in: The mating contact portion is exposed in the first groove and the second groove; The contact tail is exposed at the mounting surface; At least one of the first side wall or the second side wall includes a section adjacent to the mounting surface and a portion extending from the section to the top surface; and The portion includes at least one air flow opening therethrough.

2. The stacking connector according to claim 1, wherein: The at least one air flow opening occupies at least fifty percent of the portion of the at least one of the first sidewall or the second sidewall.

3. The stacking connector according to claim 1 or 2, characterized in that: The portion of the at least one of the first sidewall or the second sidewall is set back from the section.

4. The stacking connector according to claim 3, characterized in that: The at least one of the first sidewall or the second sidewall includes both the first sidewall and the second sidewall.

5. The stacking connector according to claim 4, characterized in that: The stackable connector is combined with a cage comprising a first side wall and a second side wall, wherein the first and second side walls of the cage abut the sections of the first and second side walls of the housing.

6. A method of operating an electronic device, the electronic device comprising: a housing including a panel having an opening therethrough; an I / O connector assembly comprising a connector and a cage mounted to a printed circuit board and exposed through an opening in the panel, wherein the cage comprises at least one channel; and a transceiver positioned within a channel of the at least one channel, The method comprises: enabling the transceiver to operate at data rates exceeding 110 Gbps; and Air is exhausted from the housing to induce air flow along a path through the cage, the path including a segment through an opening in a side wall of the connector and through a passage between a side wall of the connector and a side wall of the cage.

7. A stacking connector, the connector being of a type having a mounting surface, a mating surface perpendicular to the mounting surface, and a side surface perpendicular to the mating surface and the mounting surface, the connector comprising: A housing, the housing comprising: at least a first slot portion and a second slot portion, wherein each of the first slot portion and the second slot portion includes a slot therethrough and a wall defining the slot; first and second opposing side walls defining a chamber within the housing, wherein the first and second side walls support the first and second slot portions at the mating surface such that at least 50% of the mating surface of the housing between the first and second slot portions is open to passage of air into the chamber; A plurality of lead assemblies within the chamber, wherein each of the plurality of lead assemblies comprises: a plurality of conductive elements; and At least one insulating member holds the plurality of conductive elements so as to have gaps between the conductive elements along a row direction.

8. An electrical connector, comprising: case; a plurality of conductive elements, each of the plurality of conductive elements comprising a mating contact portion, a contact tail portion, and an intermediate portion connecting the mating contact portion and the contact tail portion, wherein the intermediate portions of the conductive elements of the plurality of conductive elements are held in at least one row within the housing; A conductive member includes a plurality of portions welded to selected ones of the conductive elements in a row, and a body elongated in the row direction to interconnect the plurality of portions.

9. An electrical connector, comprising: A plurality of lead assemblies, each of the plurality of lead assemblies comprising: A lead frame housing, wherein the lead frame housing comprises an insulating material; A plurality of conductive elements, each of which includes a mating contact portion, a contact tail portion, and an intermediate portion connecting the mating contact portion and the contact tail portion, wherein the intermediate portions of the conductive elements of the plurality of conductive elements are held in a row by the lead frame housing; and a conductive member, which includes a plurality of portions welded to a selected number of conductive elements in the row, and a body that is elongated in the row direction to interconnect the plurality of portions.

10. The electrical connector according to claim 9, characterized in that: The electrical connector further comprises: A connector housing comprising a slot partially defined by a first surface and a second surface, wherein mating contact portions of a plurality of conductive elements of a first lead assembly among the plurality of lead assemblies are exposed in the first surface, and mating contact portions of a plurality of conductive elements of a second lead assembly among the plurality of lead assemblies are exposed in the second surface.

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