Cable circuit board assembly

Abstract

The application discloses a cable circuit board assembly, which comprises a circuit board and a plurality of cables terminated to the rear end of the circuit board, the front end of the circuit board is provided with a plurality of matching conductive sheets, and the rear end is provided with a plurality of cable conductive sheets and ground conductive sheets, each cable comprises two signal conductors and a ground shield, each signal conductor is terminated to a corresponding cable conductive sheet, and further comprises a plurality of shielding members, the plurality of shielding members are terminated to corresponding ground conductive sheets, and each shielding member comprises a front opening, a bottom wall, a pair of side walls, a rear wall and a top wall.

Description

Technical Field

[0001] This invention relates to a cable circuit board assembly, and more particularly to a high-frequency, high-speed cable circuit board assembly. Background Technology

[0002] With the development of high-speed data center infrastructure driven by artificial intelligence, the required transmission rates are also increasing.

[0003] U.S. Patent No. 8,840,432 discloses a circuit board cable assembly that includes multiple grounding shields, each grounding shield having a pair of sidewalls, a top wall, and an end wall.

[0004] U.S. Patent No. 9,640,880 discloses a circuit board cable assembly including a shielding structure having a top wall and a plurality of side walls extending from the top wall.

[0005] U.S. Patent No. 12,003,061 discloses a circuit board cable assembly including a molded conductive grounding strip having opposing first and second sides, an outer wall located between the first and second sides, and a partition wall extending from the outer wall.

[0006] The grounding shield in the previous case had poor shielding performance. Summary of the Invention

[0007] The main objective of this invention is to provide a cable circuit board assembly with good performance in high-frequency and high-speed signal transmission.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a cable circuit board assembly, which includes a circuit board and multiple cables terminated to the rear end of the circuit board. The front end of the circuit board is provided with multiple mating conductive plates, and the rear end is provided with multiple cable conductive plates and grounding conductive plates. Each cable includes two signal conductors and a grounding shield. Each signal conductor is terminated to a corresponding cable conductive plate. The assembly further includes multiple shielding components, which are terminated to corresponding grounding conductive plates. Each shielding component includes a front opening, a bottom wall, a pair of side walls, a rear wall, and a top wall.

[0009] Compared with the prior art, the advantages of the cable circuit board assembly of the present invention are as follows: the shield of the present invention includes a front opening, a bottom wall, a pair of side walls, a rear wall and a top wall, so as to reduce crosstalk between the high-speed circuit board and the cable termination area, and make the cable circuit board assembly better at transmitting high-frequency and high-speed signals. Attached Figure Description

[0010] Figure 1 This is a perspective view of a cable circuit board assembly conforming to the present invention.

[0011] Figure 2 yes Figure 1The diagram shows a 3D view of the cable circuit board assembly before its final state.

[0012] Figure 3 yes Figure 1 The top view of the cable circuit board assembly shown.

[0013] Figure 4 yes Figure 2 A 3D view of the cable circuit board assembly with the cables removed.

[0014] Figure 5 yes Figure 4 An exploded view of the cable circuit board assembly shown.

[0015] Figure 6 yes Figure 4 The figure shown is a perspective view of the unfolded metal slab used to form the shielding component.

[0016] Figure 7 This is a perspective view of a second embodiment of the cable circuit board assembly conforming to the present invention.

[0017] Figure 8 yes Figure 7 The diagram shows a 3D view of the cable circuit board assembly's shielding before it has been fabricated to its final state.

[0018] Figure 9 yes Figure 7 The top view of the cable circuit board assembly shown.

[0019] Figure 10 yes Figure 7 The diagram shows a 3D view of the cable circuit board assembly equipped with pick-up and placement tools.

[0020] Figure 11 yes Figure 8 A 3D view of the cable circuit board assembly with the cables removed.

[0021] Figure 12 yes Figure 8 A perspective view of one of the shielding components shown.

[0022] Figure 13 yes Figure 12 A three-dimensional view of another state of the shielding component shown.

[0023] Figure 14 This is a cross-sectional view of the cable of the cable circuit board assembly conforming to the present invention.

[0024] Figure 15 This is a perspective view of a third embodiment of the cable circuit board assembly conforming to the present invention.

[0025] Figure 16 This is a perspective view of another embodiment of the shielding component conforming to the present invention.

[0026] Figure 17 yes Figure 12 A perspective view of the shielding component from another angle.

[0027] Figure 18 yes Figure 16 An exploded view of the aforementioned shielding component.

[0028] Figure 19 yes Figure 17 An exploded view of the shielding component from another perspective.

[0029] Component symbol explanation: Cable circuit board assemblies 100, 200, 300 Circuit board 10, cable 20, front end 102, mating conductive sheet 12, rear end 104 Cable conductive sheet 14, grounding conductive sheet 16, signal conductor 22, grounding shield 24 Shielding components 30, 50, 70, 80 Front opening 32; Bottom wall 33, 846; Side walls 34, 54, 561, 541, 842 Rear wall 35, 55, 844; Top wall 36, 76, 822 Upper floor, lower floor 242 Mounting feature 332, latching feature 342, connecting part 38, joining feature 362, connecting feature 382 Shell 540, Cover 560, Flange 52 Bending feature 542, Cutout 544, Locking feature 543 Wire 60 Pick-up and Placement Tool 61 Finger 762 upper plate 82 lower plate 84 . Detailed Implementation

[0030] like Figure 1-6The diagram shows a cable circuit board assembly 100 conforming to the present invention. The cable circuit board assembly 100 includes a circuit board 10 and cables 20 terminated at the circuit board 10. The front end 102 of the circuit board 10 has multiple mating conductive plates 12, and the rear end 104 of the circuit board 10 has multiple cable conductive plates 14 and a grounding conductive plate 16. Multiple cables 20 terminate at the rear end 104 of the circuit board 10. Each cable 20 includes two signal conductors 22 and a grounding shield 24, the two signal conductors 22 being terminated at corresponding cable conductive plates 14. Multiple shields 30 are connected to corresponding grounding conductive plates 16 to reduce crosstalk at the connection between the cables 20 and the circuit board 10. Each shield 30 has a front opening 32, a bottom wall 33, a pair of side walls 34, a rear wall 35, and a top wall 36. The shield 30 is a metal shell formed by the walls. The cables 20 are terminated on the circuit board 10 in a single row. The shields 30 shield the paired signal conductors 22 of the single row of cables. The sidewall 34 automatically shields the signal conductor pairs of two adjacent cables 20. It is well known that the cable circuit board assembly 100 can be used in pluggable modules. It is also well known that the front mating conductive plate 12 is electrically connected to the rear cable conductive plate 14 and ground conductive plate 16 via wiring traces in the circuit board 10. The shielding member 30 has not only a bottom wall 33 but also a rear wall 35 for better shielding.

[0031] The shield 30 can be formed from a flat metal plate, which can be easily manufactured by a common stamping operation. Mounting features 332 can be formed on the bottom wall 33 for positioning the shield 30 to the circuit board 10. Mounting features 332 are downwardly extending pins or posts, and the circuit board 10 has holes through which the corresponding pins or posts pass. Latch features 342 can be formed on the side wall 34 to aid in the formation of the side wall 34 itself. Latch features 342 are resilient finger-like structures stamped from the side wall 34. The top walls 36 of each shield 30 can be connected together by a connecting portion 38 between the top walls 36 of every two adjacent shields 30. The top wall 36 has a bonding feature 362 for bonding the grounding shield 24 of the cable 20. Bonding feature 362 is a resilient contact finger. When the top wall 36 is closed, the bonding feature 362 abuts against the grounding shield 24 of the corresponding cable 20. Solder can also be applied to the contact area between the bonding feature 362 and the grounding shield 24. Similarly, the connecting portion 38 has a connecting feature 382 for engaging the grounding shield 24 of a cable not surrounded by all the walls of the shield 30. The cable 20 is assembled inside the shield 30. The cable 20 is connected to the circuit board 10 by resistance welding or laser welding. The shield 30 is mounted on both sides of the circuit board 10. The shield 30 may be suitably arranged belly to belly.

[0032] like Figure 7-13The diagram shows another embodiment of the cable circuit board assembly 200, which differs primarily from the cable circuit board assembly 100 of the first embodiment in that the plurality of shielding elements 50 are independently and discretely arranged, not connected together by the connecting portion 38. Each shielding element 50 includes a housing 540 and a cover 560. The housing 540 is mounted on the circuit board, and the cover 560 is fixed to the housing 540. Both the cover 560 and the housing 540 have a pair of sidewalls 54. Specifically, the cover 560 has a pair of sidewalls 561, and the housing 540 has a pair of sidewalls 541. The sidewalls 561 are located outside the respective sidewalls 541. In this embodiment, to facilitate the arrangement of each individual shielding element 50 onto the circuit board, a flat fin 52 is formed on the shielding element 50. The fin 52 preferably extends from its rear wall 55 for operation by a pick-and-place tool 61. A bending feature 542 can also be seen bending from the sidewall 54 of the housing 540 of the shield 50. This bending feature 542 is used to terminate the connection to the grounding conductive piece 16 on the circuit board. As another way of connecting the shield 50 to the grounding shield 24 of the cable, a conductor 60 is provided to fit into a corresponding cutout 544 formed in the sidewall 54. The cable is connected to the circuit board in a back-and-forth cross configuration.

[0033] The flaps 52 of the shield 30 are connected together by a carrier tape. The shield 50 can be formed by stamping and bending a copper alloy (e.g., phosphor bronze C-5210). The flat flaps 52 of multiple shields 50 are initially connected by the carrier tape. After stamping, the locking feature 543 of the housing 540 is formed, followed by the bending feature 542 for SMT solder pads on the housing 540, the next step is to form the sidewall 541 of the housing 540, and the next step is to form the sidewall 561 of the cover 560. There is a "V-shaped cut" between the flat flaps 52 and the carrier tape to easily break the carrier tape. After the carrier tape is broken, the remaining flat flaps 52 become a pick-and-place landing pad, and the flat flaps 52 are formed in a positioning and bending jig after the carrier tape breaks. The pick-and-place tool 61 can accurately place individual shields 50 onto the circuit board. The pick-and-place landing pad provides sufficient surface area for the nozzle of the pick-and-place tool 61. Before picking up and placing the shield 50, solder paste is applied to the grounding conductive pad on the circuit board. The pick-up and place landing pad provides additional structure and support for the bending and closing of the metal housing 560. After picking up and placing, the housing 540 is reflow soldered to the housing 560 in the open position to accommodate the cable.

[0034] Figure 14A biaxial cable with two signal conductors 22 is shown, suitable for use in cable circuit board assemblies 100 or 200. The cable is a 26AWG or 28AWG groundless biaxial cable. The biaxial cable also includes an upper ground plane 242 and a lower ground plane 242. The upper and lower ground planes 242 are placed on or in contact with a grounding shield 24 and are mechanically and electrically connected to the shield. The upper and lower ground planes 242 can be part of the grounding shield 24, together forming an integral grounding shield.

[0035] Figure 15 The cable circuit board assembly 300 of the third embodiment of the present invention differs from the cable circuit board assembly 200 in that each of the plurality of shields 70 is provided with a finger 762 on its top wall 76. When the shield 70 is closed and latched, the finger 762 is used to engage the grounding shield of the cable, rather than grounding through the cable.

[0036] Figure 16-19 This is another embodiment of the shielding member 80. It includes an integral upper plate 82, which serves as a cover to define the top wall 822 of the shielding member 80. It also includes an integral lower plate 84, which is bent to define corresponding sidewalls 842, rear wall 844, and bottom wall 846 of the shielding member 80. After the cable is guided into the shielding member 80 by the sidewalls 842 and soldered into place, the upper plate 82 is connected to the lower plate 84. Spot welding can be used to eliminate gaps between the individual shielding members 80, achieving excellent crosstalk cancellation. In this embodiment, the shielding member 80 can be conveniently soldered to the grounding conductive plate of the circuit board using an automated pick-and-place reflow process. It should be noted that in this design, two adjacent shielding members 80 share a single sidewall 842, which helps save space.

[0037] This invention improves crosstalk in cable assemblies during high-speed data transmission by using shielding. The invention primarily relates to fine-pitch cable assemblies, their mounting design, and manufacturing. This invention provides a solution for reducing crosstalk in high-speed cable circuit boards and cable termination areas. The cable circuit board assembly of this invention is capable of transmitting high-speed signals of 224 Gbps or higher.

[0038] The cable circuit board assembly of this invention conforms to the OSFP specification, which defines eight transmit channels and eight receive channels, each with a signal transmission rate of 50Gbps or higher. This invention can also be applied to similar high-speed electrical connector assemblies with high transmission rates, such as SFP-DD, SFP, and QSFP-DD.

Claims

1. A cable circuit board assembly, comprising a circuit board and multiple cables terminated at the rear end of the circuit board, wherein the front end of the circuit board is provided with multiple mating conductive plates, and the rear end is provided with multiple cable conductive plates and a grounding conductive plate, each cable including two signal conductors and a grounding shield, each signal conductor being terminated at a corresponding cable conductive plate, characterized in that: It further includes multiple shielding elements, each shielding element being terminated at a corresponding grounding conductive sheet, and each shielding element including a front opening, a bottom wall, a pair of side walls, a rear wall, and a top wall.

2. The cable circuit board assembly according to claim 1, characterized in that: The cables are connected to the circuit board in a single row or in an alternating back-to-back direction.

3. The cable circuit board assembly according to claim 1, characterized in that: The cable is a 26AWG or 28AWG groundless biaxial cable. The cable is connected to the circuit board by resistance welding or laser welding. The biaxial cable also includes an upper ground plane and / or a lower ground plane. The upper ground plane is placed on or in contact with the grounding shield and is mechanically and electrically connected to the shield.

4. The cable circuit board assembly according to claim 1, characterized in that: The shielding component is formed by stamping and bending a metal plate. The top walls of multiple shielding components are connected together through the connecting part of the top walls of two adjacent shielding components. The connecting part has the feature of engaging with the grounding shield of the cable.

5. The cable circuit board assembly according to claim 1, characterized in that: The top wall of the shield is provided with elastic contact fingers for abutting against the cable grounding shield, and solder is applied between the elastic contact fingers and the grounding shield.

6. The cable circuit board assembly according to claim 1, characterized in that: The circuit board is equipped with shielding on both sides, and the shielding on both sides is arranged in a belly-to-belly manner.

7. The cable circuit board assembly as described in claim 1, characterized in that: Multiple shielding components are independent and discretely configured.

8. The cable circuit board assembly as described in claim 1, characterized in that: The shielding component includes a housing and a cover. Both the housing and the cover have a pair of sidewalls. The pair of sidewalls of the cover are located outside the pair of sidewalls of the housing. A latching feature is formed on the sidewall of the housing. The latching feature helps to form the sidewall itself and latches with the sidewall of the cover. The shielding component has flat fins that extend from the rear wall of the shielding component for picking up and placing tools to place the shielding component onto the circuit board.

9. The cable circuit board assembly as described in claim 1, characterized in that: It further includes a conductor, and the sidewall has a corresponding cutout for receiving the conductor so as to connect the shield to the grounding shield of the cable.

10. The cable circuit board assembly as claimed in claim 1, characterized in that: The shielding component includes an integral upper plate, which serves as the upper cover defining the shielding component, and an integrally bent lower plate, which defines the side wall, rear wall and bottom wall of the shielding component. Two adjacent shielding components share a side wall. The upper plate is connected to the lower plate by spot welding, and there are no gaps between the shielding components.

Images