Bonding pad embedded high-speed cable connector capable of improving crosstalk

Abstract

The utility model discloses a high-speed cable connector with an embedded bonding pad for improving crosstalk, which comprises a PCB (printed circuit board) with a plurality of wiring layers and a differential signal cable connected onto the PCB, and a pair of signal conductors and a pair of ground wire conductors are led out from the front end of the differential signal cable; the structure is characterized in that an embedded cavity penetrating into an inner wiring layer of the PCB is milled in the edge of the PCB, the front end of the differential signal cable is arranged in the embedded cavity, the bottom of the embedded cavity is the exposed inner wiring layer, and a pair of signal bonding pads are arranged on the exposed inner wiring layer and are correspondingly welded with a pair of signal conductors at the front end of the differential signal cable; a surface wiring layer of the PCB is a ground layer plane, two ground layer bonding pads located on the two sides of the embedded cavity respectively are arranged on the surface wiring layer, and a pair of ground wire conductors of the differential signal cable are arranged above the embedded cavity in a crossed mode and are correspondingly welded to the two ground layer bonding pads on the two sides respectively; and meanwhile, the surface wiring layer is provided with a ground hole surrounding the embedded cavity. According to the utility model, the crosstalk problem can be effectively improved on the premise of not occupying the transverse area of the PCB.

Description

Technical Field

[0001] This utility model relates to a pad-embedded high-speed cable connector for improving crosstalk. Background Technology

[0002] With the widespread application of AI technology and the advent of the Internet of Things era, the scale of data centers is experiencing explosive growth. Therefore, high-speed cable connectors such as 400G, 800G and 1.6T will become the best solution for dealing with large-scale data interaction and meet the various application scenarios of next-generation data centers, metropolitan area networks and edge computing.

[0003] Current high-speed cable connectors typically consist of a PCB board and differential signal cables connected to it. The outer sheath of the differential signal cables is removed, and the inner aluminum foil and insulating sheath are then cut open to expose the paired signal conductors (copper wires) encased in the insulating sheath. These conductors are then soldered to pre-set paired signal pads on the PCB board. The differential signal cables also have paired ground wires, which are soldered to paired ground pads on the PCB board to ensure signal stability. Because the aluminum foil, which provides signal shielding, is cut away from the signal conductors at the signal pads, the electromagnetic radiation from the signal conductors lacks obstruction, leading to significant crosstalk between the differential signal cables.

[0004] Because existing high-speed cable connectors typically contain multiple channels (cables) and the speed is increasing, crosstalk between channels is becoming increasingly serious. Common methods to mitigate crosstalk include staggered pad arrangement, increasing pad spacing (to increase the distance between intruding and victim signals), and adding shielding to block propagation paths. However, these methods all occupy a significant amount of PCB lateral area, compressing wiring space and making them difficult to apply perfectly within the limited internal space of the connector. Ultimately, this still results in excessive signal crosstalk between multiple channels in the connector product, leading to a decrease in overall signal transmission stability, a problem that urgently needs improvement. Summary of the Invention

[0005] The purpose of this invention is to address the problems mentioned in the background art by providing a pad-embedded high-speed cable connector that improves crosstalk, which can effectively improve the crosstalk problem between multi-channel signal cables inside the connector without occupying the lateral area of ​​the PCB board.

[0006] The technical solution of this utility model is: a high-speed cable connector with embedded pads to improve crosstalk, comprising a PCB board with multiple wiring layers and differential signal cables connected thereon, wherein a pair of signal conductors and a pair of ground conductors are led out from the front end of the differential signal cables; characterized in that the PCB board has an embedded cavity milled into its inner wiring layer at its edge, the front end of the differential signal cables is placed in the embedded cavity, and the bottom of the embedded cavity is the exposed inner wiring layer, on which a pair of signal pads are provided and soldered to the pair of signal conductors at the front end of the differential signal cables; the surface wiring layer of the PCB board is a ground plane, on which two ground pads are respectively located on both sides of the embedded cavity, and the pair of ground conductors of the differential signal cables are arranged crosswise above the embedded cavity and are respectively soldered to the two ground pads on both sides; at the same time, the PCB board has ground holes surrounding the embedded cavity.

[0007] Furthermore, in this invention, the inner wiring layer edge at the bottom of the embedded cavity is milled with a cable embedding groove for embedding the front end of the differential signal cable.

[0008] Furthermore, in this invention, the bottom of the signal conductor at the front end of the differential signal cable is flush with the inner wiring layer, thereby ensuring that the signal conductor can be soldered to the signal pads on the inner wiring layer without bending or sinking, which helps to improve the signal transmission stability of the signal conductor.

[0009] Furthermore, in this invention, the cable slot is the same width as the embedded differential signal cable.

[0010] Furthermore, in this invention, the depth of the embedded cavity is greater than the radius of the signal conductor.

[0011] Furthermore, in this invention, the bottom of the lower ground conductor in the pair of intersecting ground conductors is at a vertical distance greater than 0.5mm from the top of the signal conductor in the lower embedded cavity, so as to avoid a significant impact on the impedance of the signal pad.

[0012] Furthermore, in this invention, the ground holes extend from the surface wiring layer to any complete wiring layer below the embedded cavity, and the ground holes are distributed in a rectangular array, with the spacing between the horizontal and vertical ground holes being less than one-tenth of the wavelength corresponding to the highest frequency of the transmitted signal in the signal conductor.

[0013] Furthermore, the diameter of the boreholes described in this invention is 5 mil, while the spacing between the horizontal and vertical boreholes is 20 mil.

[0014] Furthermore, the PCB board described in this utility model includes six or more wiring layers.

[0015] Furthermore, in this invention, there are two or more differential signal cables, and the PCB board has embedded cavities milled for each differential signal cable.

[0016] The advantages of adopting the technical solution of this utility model are as follows:

[0017] 1. Compared with conventional high-speed cable connectors, this utility model does not occupy the horizontal area of ​​the PCB board. Instead, it mills an embedded cavity in the vertical direction of the PCB board to accommodate the differential signal cable. The signal pads and the soldered signal conductors are placed in the embedded cavity. The embedded cavity forms a shield-like cavity with the help of the surrounding ground holes and ground planes, which blocks the crosstalk propagation path of the internal signal conductors. This can improve the crosstalk problem between adjacent differential signal cables. At the same time, it does not compress the horizontal wiring space on the PCB board, nor does it require increasing the spacing between the signal pads of adjacent cables.

[0018] 2. Compared with conventional high-speed cable connectors, this utility model further crosses the ground conductor at the front end of the differential signal cable above the signal conductor and then solders it to the ground pad to form a shielded cavity-like cover. This confines the signal of the signal conductor within the shielded cavity, thereby better improving crosstalk and effectively enhancing the signal transmission performance and stability of this type of high-speed cable connector, further adapting to the speed-up requirements of high-speed cables.

[0019] 3. In this utility model, the bottom of the signal conductor at the front end of the differential signal cable is flush with the inner wiring layer, avoiding bending before soldering to the signal pad, which can further improve the stability of signal transmission by the signal conductor.

[0020] The purpose, advantages and features of this utility model will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of a specific embodiment of the present utility model;

[0022] Figure 2 yes Figure 1 Top view of the embodiment;

[0023] Figure 3 yes Figure 1 Front sectional view of the embodiment;

[0024] Figure 4 This is a comparison chart of the signal conductor simulation crosstalk curves of the present invention and the conventional solution.

[0025] The meanings of the labels in the figures are as follows:

[0026] 1. PCB board; 2. Differential signal cable; 3. Signal conductor; 4. Ground conductor; 5. Embedded cavity; 6. Routing layer; 601. First routing layer; 602. Second routing layer; 603. Third routing layer; 604. Fourth routing layer; 605. Fifth routing layer; 606. Sixth routing layer; 607. Seventh routing layer; 7. Signal pad; 8. Ground pad; 9. Ground via; 10. Cable tray; 11. Dielectric layer; 1101. First dielectric layer; 1102. Second dielectric layer; 1103. Third dielectric layer; 1104. Fourth dielectric layer; 1105. Fifth dielectric layer; 1106. Sixth dielectric layer; H, Depth; h, Vertical distance. Detailed Implementation

[0027] Example: The following is combined with Figures 1-4 As shown, the specific implementation of the pad-embedded high-speed cable connector for improving crosstalk provided by this utility model is described below:

[0028] This high-speed cable connector is a multi-channel product, consisting of a PCB board 1 housed within a casing (not shown in the figure) and multi-strand differential signal cables 2 connected to it. To clearly illustrate the core features of this invention... Figures 1-3 The diagram only shows the assembly structure between a single differential signal cable 2 and the PCB board 1. The differential signal cable 2 has a pair of signal conductors 3 and a pair of ground conductors 4 leading out from its front end. The structure of the differential signal cable 2 is the same as conventional technology, consisting of an outer sheath (not shown), an aluminum foil (not shown), an insulating sheath (not shown), and a pair of signal conductors 3 from the outside in, while the pair of ground conductors 4 are connected to the aluminum foil.

[0029] In this embodiment, the PCB board 1 is a seven-layer PCB with an asymmetric stacked structure, which is composed of seven independently routed wiring layers 6 and six dielectric layers 11 stacked alternately. Figure 3 As shown, and for ease of explanation, we name the seven routing layers 6 from top to bottom as first routing layer 601, second routing layer 602, third routing layer 603, fourth routing layer 604, fifth routing layer 605, sixth routing layer 606 and seventh routing layer 607, and the six dielectric layers 11 as first dielectric layer 1101, second dielectric layer 1102, third dielectric layer 1103, fourth dielectric layer 1104, fifth dielectric layer 1105 and sixth dielectric layer 1106.

[0030] All wiring layers 6 are made of copper, while the dielectric layer 11 uses Panasonic Megatron 6 substrate with a dielectric constant Dk of approximately 3.0 and a dissipation factor Df of approximately 0.004@12GHz. The thicknesses of each layer from top to bottom are as follows: First wiring layer 601: 1.57mil (0.040mm); First dielectric layer 1101: 4.0mil (0.102mm); Second wiring layer 602: 1.38mil (0.035mm); Second dielectric layer 1102: 3.5mil (0.089mm); Third wiring layer 603: 1.5mil (0.038mm); Third dielectric layer 1102: 1.5mil (0.038mm); The thickness of the 1103 layer is 6.7 mil (0.170 mm), the thickness of the fourth wiring layer 604 layer is 0.59 mil (0.015 mm), the thickness of the fourth dielectric layer 1104 layer is 3.0 mil (0.076 mm), the thickness of the fifth wiring layer 605 layer is 0.59 mil (0.015 mm), the thickness of the fifth dielectric layer 1105 layer is 3.0 mil (0.076 mm), the thickness of the seventh wiring layer 607 layer is 0.59 mil (0.015 mm), and the thickness of the sixth dielectric layer 1106 layer is 3.0 mil (0.076 mm).

[0031] Combined Figures 1-3 As shown, the core improvement of this utility model lies in the fact that the PCB board 1 has embedded cavities 5 milled into its edge, extending into the third wiring layer 603. The number of embedded cavities 5 corresponds one-to-one with the differential signal cables 2. The front end of the differential signal cable 2 is placed in the corresponding embedded cavity 5, and the bottom of the embedded cavity 5 is the exposed third wiring layer 603, on which a pair of signal pads 7 are provided, which are correspondingly soldered to a pair of signal conductors 3 at the front end of the differential signal cable 2. The first wiring layer 601 of the PCB board 1 is the surface wiring layer, which is also the ground plane. It has two ground pads 8 located on both sides of the embedded cavity 5. The pair of ground conductors 4 of the differential signal cable 2 are arranged crosswise above the embedded cavity 5 and are correspondingly soldered to the two ground pads 8 on both sides. At the same time, the PCB board 1 has ground holes 9 surrounding the embedded cavity 5.

[0032] Still combined Figures 1-3 As shown, in this embodiment, the inner wiring layer 6 at the bottom of the embedded cavity 5 has a cable recess 10 milled on its edge for embedding the front end of the differential signal cable 2, and the cable recess 10 is the same width as the embedded differential signal cable 2. Simultaneously, the bottom of the signal conductor 3 at the front end of the differential signal cable 2 is flush with the third wiring layer 603, as detailed in the diagram. Figure 3 As shown.

[0033] In this embodiment, the depth H of the embedded cavity 5 is greater than the radius of the signal conductor 3, which has a radius of 0.15 mm and a depth H of 0.266 mm.

[0034] In this embodiment, the bottom of the lower ground conductor 4 in the pair of intersecting ground conductors 4 has a vertical distance h between its bottom and the top of the signal conductor 3 in the lower embedded cavity 5 that is greater than 0.5 mm, and in this embodiment, it is taken as 0.8 mm.

[0035] In this embodiment, the ground vias 9 extend from the first wiring layer 601 on the surface to the seventh wiring layer 607 below the embedded cavity 5. The ground vias 9 are arranged in a rectangular array, with the spacing between the horizontal rows and the vertical rows of ground vias 9 being less than one-tenth of the wavelength corresponding to the highest frequency of the transmitted signal in the signal conductor 3. In this embodiment, the diameter of the ground vias 9 is 5 mil, while the spacing between the horizontal rows and the vertical rows of ground vias 9 is 20 mil.

[0036] The following is a comparison of the signal conductor simulation crosstalk curves of the scheme in this embodiment and the conventional scheme in 3D electromagnetic field simulation software. Figure 4 As shown, the horizontal axis represents frequency, and the vertical axis represents the crosstalk between adjacent channels of signal conductor 3 in the simulation model PCB board. Curve m1 in the figure is the crosstalk curve of signal conductor 3 in the conventional scheme, while m2 is the crosstalk curve of signal conductor 3 in this scheme. It can be seen that compared with the conventional scheme, this scheme significantly reduces crosstalk across the entire frequency band, from ≤ -39.3dB to ≤ -59dB, a reduction of 19.7dB, or approximately 50%. The significant reduction in crosstalk can effectively reduce the mutual influence between signal transmission channels and the radiation emitted during signal transmission, thereby greatly improving the signal transmission quality.

[0037] Of course, the above are merely specific application examples of this utility model and do not constitute any limitation on the scope of protection of this utility model. In addition to the above embodiments, this utility model may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by this utility model.

Claims

1. A pad-embedded high-speed cable connector for improving crosstalk, comprising a PCB board (1) having multiple wiring layers (6) and differential signal cables (2) connected thereto, wherein a pair of signal conductors (3) and a pair of ground conductors (4) are led out from the front end of the differential signal cables (2); characterized in that, The PCB board (1) has an embedded cavity (5) milled into its inner wiring layer (6) at its edge. The front end of the differential signal cable (2) is placed in the embedded cavity (5), and the bottom of the embedded cavity (5) is the exposed inner wiring layer (6), on which a pair of signal pads (7) are provided, which are correspondingly soldered to a pair of signal conductors (3) at the front end of the differential signal cable (2). The surface wiring layer (6) of the PCB board (1) is a ground plane, on which two ground pads (8) are respectively located on both sides of the embedded cavity (5). The pair of ground conductors (4) of the differential signal cable (2) are arranged crosswise above the embedded cavity (5) and are respectively soldered to the two ground pads (8) on both sides. At the same time, the PCB board (1) has a ground hole (9) surrounding the embedded cavity (5).

2. The pad-embedded high-speed cable connector for improving crosstalk according to claim 1, characterized in that, The inner wiring layer (6) at the bottom of the embedded cavity (5) has a cable groove (10) milled on its edge for the front end of the differential signal cable (2) to be embedded.

3. A pad-embedded high-speed cable connector for improving crosstalk according to claim 2, characterized in that, The bottom of the signal conductor (3) at the front end of the differential signal cable (2) is flush with the inner wiring layer (6).

4. A pad-embedded high-speed cable connector for improving crosstalk according to claim 2, characterized in that, The cable slot (10) is the same width as the embedded differential signal cable (2).

5. A pad-embedded high-speed cable connector for improving crosstalk according to claim 1, characterized in that, The depth (H) of the embedded cavity (5) is greater than the radius of the signal conductor (3).

6. A pad-embedded high-speed cable connector for improving crosstalk according to claim 1, 2, or 3, characterized in that, The bottom of the lower ground conductor (4) in the pair of cross-connected ground conductors (4) has a vertical distance (h) greater than 0.5 mm from the top of the signal conductor (3) in the lower embedded cavity (5).

7. A pad-embedded high-speed cable connector for improving crosstalk according to claim 1, characterized in that, The ground vias (9) extend from the surface wiring layer (6) to any complete wiring layer (6) below the embedded cavity (5), and the ground vias (9) are distributed in a rectangular array. The spacing between the horizontal and vertical rows of ground vias (9) is less than one-tenth of the wavelength corresponding to the highest frequency of the transmitted signal in the signal conductor (3).

8. A pad-embedded high-speed cable connector for improving crosstalk according to claim 7, characterized in that, The diameter of the borehole (9) is 5 mil, and the spacing between the horizontal and vertical boreholes (9) is 20 mil.

9. A pad-embedded high-speed cable connector for improving crosstalk according to claim 1, characterized in that, The PCB board (1) includes six or more wiring layers (6).

10. A pad-embedded high-speed cable connector for improving crosstalk according to claim 1, characterized in that, The differential signal cable (2) consists of two or more cables, and the PCB board (1) has the embedded cavity (5) milled on each differential signal cable (2).

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