Printed circuit board and via hole arrangement method thereof
By setting a resonant cavity-like structure on the printed circuit board, the crosstalk and insertion loss problems of signal vias are solved, achieving high signal quality at high signal speeds and improving the bandwidth and isolation of the signal channel.
Patent Information
- Application Number
- CN202410581134.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-10
- Publication Date
- 2025-11-11
AI Technical Summary
In the prior art, the via arrangement of printed circuit boards (PCBs) cannot meet the high signal quality requirements at high signal speeds, especially due to crosstalk and insertion loss issues of signal vias.
A cavity-like structure is set on the printed circuit board. By setting a first ground part and a second ground part on the first and second sides of the signal via, the structure surrounds the signal via to form a cavity-like structure, thereby improving the bandwidth of the signal channel and reducing crosstalk.
At high signal speeds, it significantly improves signal quality, reduces insertion loss and crosstalk, and meets the requirements for high signal quality.
Smart Images
Figure CN120935924A_ABST
Abstract
Description
Technical Field
[0001] This application relates to, but is not limited to, the field of communication technology, and particularly to a printed circuit board and a method for arranging vias on a printed circuit board. Background Technology
[0002] With the rapid development of the electronic communications industry, the complexity and integration of communication equipment have greatly increased, leading to increasingly higher requirements for signal rates, especially electrical and signal integrity performance (SI performance). When communication equipment relies on PCBs (Printed Circuit Boards) for high-speed signal interconnection, the via arrangement design on the PCB plays a crucial role. As signal rates increase, the via arrangement has a more significant impact on performance indicators such as insertion loss and crosstalk of signals passing through the vias, meaning it has a greater impact on signal quality. Current PCB via arrangements cannot meet these higher signal quality requirements. Therefore, how to enable PCBs to meet high signal quality requirements under high signal rates is a pressing technical problem that needs to be solved. Summary of the Invention
[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.
[0004] This application provides a printed circuit board and a via arrangement method for the printed circuit board, which enables the PCB to meet high signal quality requirements under high signal speed conditions.
[0005] In a first aspect, a printed circuit board provided according to an embodiment of this application includes a plurality of ground pads and at least one signal pad, each of the ground pads being provided with a first ground portion; the signal pad is located between two of the ground pads, and each of the signal pads is electrically connected to a signal via; a second ground portion is provided on the first ground portion and the first side of the signal via, and the first ground portion and the second ground portion together form a resonant cavity-like structure that surrounds the signal via.
[0006] Secondly, according to the via arrangement method of the printed circuit board provided in the embodiments of this application, the method includes: obtaining the pad size, pad spacing, and drilling diameter of the signal via electrically connected to the signal pad; the signal pad is located between two adjacent ground pads, and each ground pad is connected to a first ground portion; determining a first position on a first side of the signal via and the first ground portion according to the drilling diameter, the pad size, and the pad spacing, wherein the first position is the position that has the greatest impact on the channel performance of the signal via; and setting a second ground portion at the first position so that the first ground portion and the second ground portion surround and form a resonant cavity-like structure that encloses the signal via.
[0007] This application embodiment provides a second grounding portion on the first side of the first grounding portion and the signal via, so that the first grounding portion and the second grounding portion can surround the signal via to form a resonant cavity structure. This can increase the bandwidth of the signal channel corresponding to the signal via on the PCB. Therefore, this application embodiment enables the PCB to meet high signal quality requirements under high signal speed conditions. Attached Figure Description
[0008] Figure 1 This refers to the via arrangement structure on a PCB in the existing technology;
[0009] Figure 2 A schematic diagram of the via arrangement structure in the printed circuit board provided in this application;
[0010] Figure 3 A schematic diagram of the via arrangement structure of one embodiment of the printed circuit board provided in this application;
[0011] Figure 4 A schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0012] Figure 5 A schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0013] Figure 6a A schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0014] Figure 6b A schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0015] Figure 7a A schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0016] Figure 7bA schematic diagram of the via arrangement structure of another embodiment of the printed circuit board provided in this application;
[0017] Figure 8a A schematic diagram of the loss curve of the optical module connector corresponding to the printed circuit board provided in this application in a 112G scenario;
[0018] Figure 8b A schematic diagram of the crosstalk curve of the optical module connector corresponding to the printed circuit board provided in this application in a 112G scenario;
[0019] Figure 9a A schematic diagram of the loss curve of the optical module connector corresponding to the printed circuit board provided in this application in a 224G scenario;
[0020] Figure 9b A schematic diagram of the crosstalk curve of the optical module connector corresponding to the printed circuit board provided in this application in a 224G scenario;
[0021] Figure 10 This is a flowchart illustrating the via arrangement method for the printed circuit board provided in this application.
[0022] Figure label:
[0023] Ground pad 100, first grounding portion 110, ground via 120, first ground via 121, third ground via 122, fourth ground via 123, third metallization groove 131, ground wire 140.
[0024] Second grounding portion 210, third grounding portion 220, second ground via 230, first metallization groove 240, second metallization groove 250, fifth ground via 260
[0025] Signal pad 300, signal via 310, signal transmission line 320, inner layer trace 330. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0027] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.
[0028] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.
[0029] With the rapid development of the electronic communications industry, the complexity and integration of communication equipment have greatly increased, leading to increasingly higher requirements for signal rates, especially electrical and signal integrity performance (SI performance). When communication equipment relies on PCBs (Printed Circuit Boards) for high-speed signal interconnection, the via arrangement design on the PCB (i.e., the relative positioning of grounding and signal transmission sections) plays a crucial role. Taking the optical module connector, a common connection structure in high-speed systems, as an example, optical module connectors enable high-speed signal interconnection of optical module connector assemblies. For instance, Figure 1 The optical module connector in the prior art shown includes two signal pads 300 and a signal via 310 connected to the signal pads 300 in its signal transmission section; and a grounding section including a ground pad 100 and a ground via 120 connected to the ground pad 100. In this case, as... Figure 1 The two ground vias 120 shown are distributed on both sides of the signal via 310. The ground vias 120 do not completely enclose the signal via 310, which may cause crosstalk in the signal via 310 and increase insertion loss in the signal channel, resulting in reduced bandwidth. As the signal rate increases, the via arrangement has a more significant impact on the insertion loss, crosstalk, and other performance indicators of the signal in the signal via 310, meaning it has a greater impact on signal quality. Therefore, the via arrangement in existing PCBs cannot meet the high signal quality requirements at higher speeds. Thus, how to enable PCBs to meet high signal quality requirements at high signal rates is a pressing technical problem. Based on this, this application provides a printed circuit board and a via arrangement method for the printed circuit board, enabling the PCB to meet high signal quality requirements at high signal rates.
[0030] It should be noted that the embodiments of this application mainly focus on improving the via arrangement structure on the PCB. Therefore, the accompanying drawings only show a schematic diagram of the via arrangement structure.
[0031] Reference Figure 2 As shown, a printed circuit board provided according to an embodiment of this application includes:
[0032] Multiple ground pads 100, each ground pad 100 is provided with a first grounding part 110;
[0033] At least one signal pad 300 is located between two ground pads 100. Each signal pad 300 is provided with a corresponding signal via 310. A second ground part 210 is provided on the first side of the first ground part 110 and the first ground part 310. The first ground part 110 and the second ground part 210 enclose each other to form a resonant cavity structure that surrounds the signal via 310.
[0034] Therefore, by providing a second grounding portion 210 on the first side of the first grounding portion 110 and the signal via 310, the first grounding portion 110 and the second grounding portion 210 can surround the signal via 310 to form a resonant cavity structure. This can increase the bandwidth of the signal channel corresponding to the signal via 310 on the PCB. Therefore, the embodiments of this application enable the PCB to meet the high signal quality requirements under high signal speed conditions.
[0035] It should be noted that both the first grounding part 110 and the second grounding part 210 are used for grounding. The embodiments of this application do not limit the shape of the first grounding part 110 and the second grounding part 210. For example, the first grounding part 110 may be set as a hole or a groove. The second grounding part 210 may be set as a hole or a groove.
[0036] It should be noted that the number of signal pads 300 is not limited in this application embodiment; one or more signal pads 300 can be provided. Similarly, the number of signal vias 310 is not limited; one or more signal vias 310 can be provided on one signal pad 300. Those skilled in the art can selectively configure this according to actual needs. For example, when multiple signal pads 300 are provided, the via arrangement on the PCB board in this application embodiment can reduce signal crosstalk between the signal vias 310 of the multiple signal pads 300. When only one signal pad 300 is provided, signal crosstalk between signals passing through the signal via 310 of the signal pad 300 and other signals (signals not passing through the signal via 310) can also be reduced.
[0037] It should be noted that the dimensions of the first grounding portion 110 and the second grounding portion 210 can be the same or different. Taking the first grounding portion 110 and the second grounding portion 210 as both being hole-shaped as an example, when the distance between the ground pad 100 and the signal pad 300 is large enough, the size of the second grounding portion 210 can be increased so that the first grounding portion 110 and the second grounding portion 210 can better wrap the signal via 310. Alternatively, the second grounding portion 210 can be set as a ground via 120 with the same hole diameter as the first grounding portion 110. By adjusting the position of the ground via 120 on the first side, the first grounding portion 110 and the second grounding portion 210 can better wrap the signal via 310.
[0038] It should be noted that the relative positions of the signal via 310 and the corresponding signal pad 300 are not limited in this embodiment of the application, nor are the relative positions of the first ground portion 110 and the corresponding ground pad 100.
[0039] Understandably, referring to Figure 3 As shown, the first grounding part 110 is configured as a first ground via 121; the second grounding part 210 is configured as a second ground via 230.
[0040] It should be noted that the smaller the aperture of the signal via 310, the better it is for improving the signal bandwidth. The larger the aperture of the first ground via 121 and the second ground via 230, the smaller the distance between the signal via 310 and the ground via wall, which is also beneficial for improving the signal bandwidth.
[0041] It should be noted that the drilling diameters of the first ground via 121 and the second ground via 230 can be selectively set according to actual needs. The drilling diameter of the signal via 310 can also be selectively set according to actual needs. In some embodiments, to further improve signal integrity, after determining the minimum process drilling diameter achievable by the process capability, the drilling diameter of the signal via 310 is typically set to a value closest to that minimum process drilling diameter according to functional requirements. When determining the safe distance between two adjacent holes, the larger the drilling diameter of the ground via is set, the better, provided that the distance between the ground via and other holes is greater than the safe distance. For example, if the minimum process drill hole diameter is 0.1 mm, the safety spacing is 0.2 mm, and the maximum drill hole diameter due to layout space is 0.9 mm, then the signal via 310 can be set to 0.1 mm or larger; the drill hole diameters of the first ground via 121 and the second ground via 230 are within the range of [0.1 mm, 0.9 mm], and the spacing between the first ground via 121, the second ground via 230, and the signal via is greater than 0.2 mm. The larger the drill hole diameters of the first ground via 121 and the second ground via 230, the smaller the drill hole diameter of the signal via 310, and the better the signal quality through the signal via 310.
[0042] Understandably, referring to Figure 3 As shown, signal pads 300 are provided with at least two, and the first ground via 121 is aligned with the center of the signal via 310; two adjacent signal vias 310 located on different signal pads 300 are aligned with the center, and the first center distance between the two aligned signal vias 310 is greater than or equal to the second center distance, which is the center distance between the first ground via 121 and the nearest aligned signal via 310.
[0043] It should be noted that the smaller the first center spacing, the better it is to improve the signal bandwidth. For example, the first center spacing d1 < 0.6mm.
[0044] It should be noted that the location of the second ground via 230 is the position that has the greatest impact on the channel performance of the signal via 310.
[0045] For example, such as Figures 2-4 As shown, when the first center spacing d1 ≥ the second center spacing d2, the enclosing space formed by the first ground via 121 and the second ground via 230 can further enhance the signal bandwidth of the signal via 310, thereby improving the signal quality.
[0046] Understandably, the first center-to-center spacing of the two center-aligned signal vias 310 is greater than or equal to the third center-to-center spacing, which is the center-to-center distance between the second ground via 230 and the nearest signal via 310.
[0047] It should be noted that the smaller the spacing between the third centers, the better it is for increasing the signal bandwidth.
[0048] For example, refer to Figure 3 As shown, when the first center spacing d1 ≥ the third center spacing d3, the enclosing space formed by the first ground via 121 and the second ground via 230 can further enhance the signal bandwidth of the signal via 310, thereby improving the signal quality.
[0049] Understandably, referring to Figure 3 As shown, the plurality of ground pads 100 include a first pad, a first ground portion 110 on the first pad is configured as a first ground via 121; a corresponding third ground via 122 is provided on the first side of each first ground via 121, and the third ground via 122 is aligned with the center of the corresponding first ground via 121; a second ground portion 210 is located between the third ground via 122 and the signal via 310.
[0050] It should be noted that the first ground via 121, the third ground via 122, and the second ground portion 210 form a resonant cavity-like structure that encloses the signal via 310. When sufficient layout space is available on the PCB, adding the third ground via 122 can further improve the enclosure of the ground via 120 around the signal via 310, resulting in a larger signal bandwidth and higher signal quality.
[0051] It should be noted that the number of third ground vias 122 is not limited in the embodiments of this application, and those skilled in the art can selectively set them according to actual needs. For example, each first ground pad 100 may be provided with one third ground via 122, or each first ground pad 100 may be provided with multiple third ground vias 122.
[0052] For example, such as Figure 3As shown, each first pad is provided with a first ground via 121, and a third ground via 122 is provided on the first side of each first ground via 121. The first ground via 121 and the corresponding third ground via 122 are aligned at the center.
[0053] Understandably, such as Figure 3 and Figure 4 As shown, the first ground pad 100 is also provided with at least one fourth ground via 123. The fourth ground vias 123 are equally distributed on the second side of the first ground via 121, and the fourth ground vias 123 are aligned with the center of the corresponding first ground via 121.
[0054] It should be noted that the fourth via 123, while maintaining the complete resonant cavity structure, can also suppress crosstalk between adjacent signal channels.
[0055] It should be noted that the embodiments of this application do not limit the number of fourth ground vias 123 on each first pad, and those skilled in the art can selectively set them according to actual needs.
[0056] It should be noted that the fourth ground via 123 can be entirely placed on the first ground pad, or it can be partially placed on the first ground pad (e.g., Figure 3 (as shown) and the other parts are located between the first ground pad and the first ground portion 110 (e.g. Figure 7b (As shown). In this embodiment, the signal via 310 can be selectively configured based on its position.
[0057] For example, such as Figure 3 As shown, each first ground pad is provided with a first ground via 121, and each first pad is also provided with three fourth ground vias 123, the three fourth ground vias 123 and the corresponding first ground vias 121 are aligned at the center.
[0058] It is understandable that the distance between the third ground via 122 and the first ground via 121 on the same first ground pad is equal to the distance between the adjacent fourth ground via 123 and the first ground via 121 on the same first ground pad 100.
[0059] It should be noted that arranging the third ground via 122, the first ground via 121, and the fourth ground via 123 at equal intervals can facilitate processing and further improve signal bandwidth.
[0060] It should be noted that when multiple fourth ground vias 123 are provided, the fourth ground vias 123 can be arranged at equal intervals, such that the fourth center distance between two adjacent fourth ground vias 123 of the same first ground pad 100 is equal to the distance d4 between the third ground via 122 and the first ground via 121.
[0061] For example, such as Figure 3 As shown, three fourth ground vias 123 are arranged sequentially from left to right on the first ground pad. The distance d5 between the first ground via 121 and the adjacent fourth ground via 123 is equal to the distance d4 between the third ground via 122 and the first ground via 121 on the same ground pad 100. At this time, the ground vias 120 corresponding to the same first ground pad are arranged at equal intervals and the centers of all vias 120 are aligned.
[0062] Understandably, referring to Figure 4 and Figure 5 As shown, a third grounding portion 220 is provided on the side of the ground pad 100 and the signal pad 300 away from the signal via 310. The third grounding portion 220, the first grounding portion 110 and the second grounding portion 210 together form a resonant cavity structure that surrounds the signal via 310.
[0063] It should be noted that the third grounding part 220 is used for grounding. The specific shape of the third grounding part 220 is not limited in the embodiments of this application. Those skilled in the art can selectively set it into a hole-shaped, groove-shaped or other structural shape according to actual needs.
[0064] It should be noted that the first grounding part 110, the second grounding part 210 and the third grounding part 220 can be combined in a suitable structural shape according to the requirements. For example, the first grounding part 110 can be set as a hole, and the second grounding part 210 and the third grounding part 220 can be set as a groove. Or, the first grounding part 110, the second grounding part 210 and the third grounding part 220 can all be set as holes.
[0065] It should be noted that the horizontal distance between the third grounding part 220 and the ground pad 100 can be set to be greater than the pad impedance distance. The pad impedance distance is the minimum distance that affects the pad impedance. For example, if the pad impedance distance is 0.5mm, then the horizontal distance d6 between the third grounding part 220 and the ground pad 100 is greater than 0.5mm, thereby reducing the impact on the pad impedance.
[0066] It should be noted that adding a third grounding part 220 can further optimize signal bandwidth and crosstalk performance.
[0067] Understandably, referring to Figure 4 As shown, the third grounding portion 220 is composed of a plurality of spaced fifth ground vias arranged in columns; the first grounding portion 110 is configured as a first ground via 121; the two fifth ground vias located at the ends of the third grounding portion 220 are respectively aligned with the center of the first ground via 121 of a ground pad 100.
[0068] It should be noted that the fifth via 260 can be in one or more columns, and the number of fifth vias 260 in each column is greater than or equal to the number of pads. Therefore, this application embodiment does not limit the arrangement of the fifth vias 260; those skilled in the art can selectively set them according to the spatial layout.
[0069] It should be noted that a fifth ground via 260 may be provided on one side of the end of each ground pad 100, and the fifth ground via 260 and the corresponding first ground via 121 may be aligned in the center. This application embodiment does not limit this.
[0070] It should be noted that the first ground via 121, the second ground via 230, the third ground via 122, the fourth ground via 123, and the fifth ground via 260 are different types of ground vias 120 for different purposes. In some embodiments, the fourth ground via 123 may be omitted, and only the first ground via 121, the fifth ground via 260, and the second ground via 230 may be provided. In other embodiments, the first ground via 121, the fifth ground via 260, the fourth ground via 123, and the third ground via 122 may be provided. This application does not impose limitations on this, and those skilled in the art can selectively provide the type and quantity of ground vias 120 according to the spatial layout.
[0071] For example, such as Figure 4 As shown, there are two ground pads 100, both of which are first ground pads. Each first ground pad has one first ground via 121, three fourth ground vias 123, one third ground via 122, and one second ground via. A fifth ground via 260 is correspondingly provided at the ends of both the signal pad 300 and the first ground pads. Figure 4 As shown, there are four pads and four fifth ground vias arranged in columns.
[0072] Understandably, the third grounding part 220 is configured as the first metallization groove 240.
[0073] For example, such as Figure 5 As shown, there are two ground pads 100, both of which are first ground pads. The third grounding portion 220 at the end of the first ground pad and the signal pad 300 is a first metallization groove 240, which can improve the resonant cavity structure.
[0074] It should be noted that the horizontal distance d6 between the adjacent ends of the first metallization groove 240 and the ground pad 100 and signal pad 300 is less than the pad impedance distance.
[0075] Understandably, referring to Figure 5 As shown, the second grounding part 210 is configured as a second metallization groove 250.
[0076] It should be noted that by setting the second grounding part 210 as the second metallization groove 250, both the third grounding part 220 and the second grounding part 210 are metallization grooves, which can improve the resonant cavity structure.
[0077] It should be noted that the length and layout of the second metallization groove 250 can be selectively set according to actual needs. This application embodiment does not impose any restrictions on this. Figure 5 As shown, the second metallization groove 250 is vertically arranged. In other embodiments, the second metallization groove 250 may also be inclined.
[0078] It should be noted that the outline of the second metallization groove 250 is not limited in this embodiment. It can be set as a square groove structure, an elliptical groove structure, or a structure of other shapes.
[0079] It should be noted that the embodiments of this application do not limit the width, depth and length of the second metallization groove 250, and those skilled in the art can selectively set them according to their needs.
[0080] Understandably, referring to Figure 5 As shown, the first grounding part 110 is configured as a third metallization groove 131. The length of the third metallization groove 131 is greater than the corresponding ground pad 100, and both ends of the third metallization groove 131 protrude from the ends of the corresponding ground pad 100.
[0081] For example, such as Figure 5 As shown, the signal via 310 is surrounded by a first metallization groove 240, a second metallization groove 250 and a third metallization groove 131, thereby forming a resonant cavity-like structure.
[0082] It should be noted that the first grounding part 110 in the above embodiments of this application can be disposed on the corresponding ground pad 100 or on the first side of the corresponding ground pad 100. In this case, the first grounding part 110 can be connected to the corresponding ground pad 100 through the ground line of the PCB surface.
[0083] It should be noted that the signal via 310 in the above embodiments of this application can be disposed on the corresponding signal pad 300 or on the first side of the corresponding signal pad 300. When located on the first side of the signal pad 300, the signal via 310 can be electrically connected to the corresponding signal pad 300 through the signal transmission line 320 of the PCB. It should be noted that, as... Figures 2 to 4 As shown, the signal via 310 can use the inner layer trace 330 for signal transmission. When the inner layer trace 330 is used for signal transmission, the distance between the second ground part 210 and the inner layer trace 330 is greater than or equal to the safety distance.
[0084] It should be noted that the shapes of the ground pad 100 and signal pad 300 are not limited in this embodiment, and those skilled in the art can selectively set them according to actual needs. Taking the ground pad 100 and signal pad 300 having the same shape as an example, such as... Figures 2 to 5 As shown, all pads are set to square, such as Figure 6a As shown, all pads are set to elliptical shapes, such as... Figure 6b As shown, the pads are all set to an elliptical shape consistent with the shape of the playground. In some other embodiments, the ground pad 100 and the signal pad 300 may have different shapes, which will not be described in detail in this application.
[0085] Therefore, using the PCB provided in the above example, a via arrangement design is implemented on the PCB, forming a signal channel composed of signal pads 300, signal transmission lines 320, and signal vias 310, and a return channel composed of ground pads 100, ground lines 140, and grounding portions surrounding the signal channel. The grounding portions surround the signal channel, forming a resonant cavity-like structure. Adjusting the position of the surrounding grounding portions can change the insertion loss and return loss characteristics of the internal signal channel. On the other hand, the more complete the grounding portions are, the higher the isolation between different signal channels and the lower the crosstalk between channels. Furthermore, signal performance can be improved by introducing second grounding portions 210, third grounding portions 220, etc., without involving board material upgrades or process capability upgrades, having minimal impact on process costs, while significantly improving insertion loss and crosstalk characteristics, and is universally applicable to the PCB design of various optical module connectors.
[0086] Exemplary examples are further described below with reference to the accompanying drawings, specifically the PCB of an embodiment of this application:
[0087] like Figure 6a Example 1 and Figure 6bExample 2, where, in Example 1, both the ground pad 100 and the signal pad 300 are elliptical in shape. There are two ground pads 100 and two signal pads 300, positioned between the two ground pads 100. Each ground pad 100 has one first ground via 121, three fourth ground vias 123, and one second ground via 230. The first ground via 121 is connected to the corresponding ground pad 100 via a ground line 140. The signal via 310 is connected to the corresponding signal pad 300 via a signal transmission line 320. In Example 2, both the ground pad 100 and the signal pad 300 are elliptical in shape, resembling a playground. Two ground pads 100 and two signal pads 300 are provided, with each signal pad 300 positioned between two ground pads 100. Each ground pad 100 has one first ground via 121, three fourth ground vias 123, one second ground via 230, and one third ground via 122. For Examples 1 and 2, the first ground via 121, third ground via 122, and fourth ground via 123 on each ground pad 100 are center-aligned and equally spaced. The second center-to-center distance d2 between the first ground via 121 and the nearest signal via 310 is less than or equal to the first center-to-center distance d1 between the two signal vias 310. The distance d4 between the third ground via 122 and the corresponding first ground via 121 is equal to the distance d5 between the first ground via 121 and the adjacent fourth ground via 123 on the same ground pad 100; the third center spacing d3 between the second ground via 230 and the nearest signal via 310 is less than or equal to the first center spacing d1.
[0088] like Figure 5 Example 3 and Figure 4In Example 4, as shown in Example 3, two ground pads 100 and two signal pads 300 are provided. The two signal pads 300 are positioned between the two ground pads 100. In Example 3, the first ground portion 110, the second ground portion 210, and the third ground portion 220 are all configured as metallization grooves. The third ground portion 220 extends as a first metallization groove 240 to the ends of the two ground pads 100, such that the pads are positioned along the length of the first metallization groove 240. The first ground portion 110 serves as a third metallization groove 131, with its two ends extending to the two ends of the corresponding ground pads 100 and respectively enclosing the signal vias 310 with the first metallization groove 240 and the two second ground portions 210 serving as second metallization grooves 250 to form a resonant cavity-like structure. The horizontal distance d6 between the first metallization groove 240 and the pad is greater than the pad impedance distance. In Example 4, the first ground portion 110, the second ground portion 210, and the third ground portion 220 are all configured as ground vias 120. The fifth ground via 260 of the third ground portion 220 is longitudinally positioned along the same side end of the pad and extends to the ends of the two ground pads 100. Three fourth ground vias 123 are also provided between the fifth ground via 260 and the first ground via 121. In this case, the first ground via 121, the second ground via 230, the third ground via 122, the fourth ground via 123, and the fifth ground via 260 are distributed around the signal via 310, forming a resonant cavity-like structure. The horizontal distance d6 between the fifth ground via 260 and the pad is greater than the impedance distance.
[0089] like Figure 3 Example 5 shown Figure 7a Example 6 shown and Figure 7b Example 7 shown is in Example 5, as... Figure 3 As shown, there are two ground pads 100 and two signal pads 300. The two signal pads 300 are positioned between the two ground pads 100. A first ground via 121 is connected to the ground pad 100 via a ground line 140 and is located on the end of the corresponding ground pad 100 near the signal via 310. The signal via 310 is positioned on the first side of the signal pad 300 via a signal transmission line 320. Fourth ground vias 123 are all positioned on the corresponding ground pads 100. In Example 6, as... Figure 7aAs shown, there are two ground pads 100 and two signal pads 300. The two signal pads 300 are positioned between the two ground pads 100. A first ground via 121 is positioned at one end of the ground pad 100, and there are two fourth ground vias 123. A signal via 310 is positioned on the corresponding signal pad 300. The signal via 310 and the first ground via 121 are center-aligned. A third ground via 122 is center-aligned on the first side of each first ground via 121. The third center distance d3 between the second ground via 230 and the nearest signal via 310, and the second center distance d2 between the first ground via 121 and the nearest signal via 310 are both less than or equal to the first center distance d1 between the two center-aligned signal vias 310. In Example 7, as shown... Figure 7b As shown, the signal via 310 extends beyond the signal pad 300 via the signal transmission line 320. The first ground via 121 is located outside the ground pad 100 and on the side of the ground pad 100 near the end of the signal via 310. A portion of the fourth ground via 123 is connected to the ground pad 100 via the ground line 140, and a portion of the fourth ground via 123 is located between the corresponding ground pad 100 and the first ground via 121. At this time, the fourth ground via 123, the first ground via 121, the second ground via 230, and the third ground via 122 are adaptively adjusted according to the position of the signal via 310. In Examples 5 to 7, the first ground via 121, the third ground via 122, and the fourth ground via 123 corresponding to the same ground pad 100 are all center-aligned, and the distance between the ground vias 120 is the same.
[0090] Therefore, the above embodiments of this application can achieve high signal quality requirements on the PCB under high signal speed conditions. For example, taking an optical module connector where this application is applied and the connector has a second ground via 230, a third ground via 122, and a fourth ground via 123, simulations of insertion loss and interference performance at 112G and 224G are performed respectively, and the results are as follows... Figures 8a-9b As shown. Figure 8a As shown, in a 112G scenario, the optical module connector fabricated using the PCB of this application embodiment has a larger bandwidth drop point on the horizontal axis compared to a traditional optical module connector (i.e., the insertion loss curve shown in Figure A). This means it has a larger bandwidth and therefore higher signal transmission quality. Similarly, regarding crosstalk performance, as... Figure 8b As shown, in the 112G scenario, at the same frequency, the ordinate value of crosstalk curve B is smaller than that of crosstalk curve A. That is, the crosstalk curve B of this embodiment has a smaller crosstalk magnitude than the crosstalk curve A of the optical module connector in the prior art. Therefore, the signal quality of this embodiment is better. Figure 9aAs shown, in a 224G scenario, the optical module connector fabricated using the PCB of this application embodiment has a larger bandwidth drop point on the horizontal axis compared to a traditional optical module connector (i.e., the insertion loss curve shown in Figure A). This means it has a larger bandwidth and therefore higher signal transmission quality. Similarly, regarding crosstalk performance, as... Figure 9b As shown, in the 224G scenario, the vertical coordinate value of the crosstalk curve B is smaller than that of the crosstalk curve A at the same frequency. That is, the crosstalk curve B of this embodiment has a smaller crosstalk magnitude than the crosstalk curve A of the optical module connector in the prior art. Therefore, the signal quality of this embodiment is better.
[0091] It should be noted that the dashed line in the attached figure indicates that the center alignment of the ground via 120 passing through the line is achieved.
[0092] Understandably, such as Figure 10 As shown in the embodiments of this application, a method for arranging vias on a printed circuit board is also provided, the method comprising:
[0093] Step S100: Obtain the pad size, pad spacing, and drill diameter of the signal via 310 electrically connected to the signal pad 300; the signal pad 300 is located between two adjacent ground pads 100, and each ground pad 100 is connected to a first grounding portion 110.
[0094] Step S200: Determine the first position located on the first side of the signal via 310 and the first ground portion 110 based on the drill hole diameter, pad size and pad spacing, wherein the first position is the position that has the greatest impact on the channel performance of the signal via 310.
[0095] Step S300: Set a second grounding part 210 at the first position so that the first grounding part 110 and the second grounding part 210 surround and form a resonant cavity structure that encloses the signal via 310.
[0096] It should be noted that the pad spacing refers to the distance between the signal pad 300 and the adjacent ground pad 100.
[0097] For example, refer to Figures 3 to 7b The illustrated embodiment describes a via arrangement method according to an embodiment of this application. The signal via 310 can have a drill diameter of 0.2 mm or less. A small diameter for the signal via 310 is beneficial for increasing the signal bandwidth. The ground via 120 can have a drill diameter of 0.2 mm or more. A large diameter for the ground via can reduce the distance between the signal via 310 and the ground via wall, which is beneficial for increasing the signal bandwidth. At this time, the following steps are performed to obtain... Figure 3 The via arrangement structure on the PCB is shown.
[0098] First, the center-to-center spacing d1 between signal vias 310 is set to be less than 0.6mm to ensure a small spacing between the signal vias 310, which is beneficial for improving signal bandwidth. Based on the degree of impact on channel performance, the first position of the second ground via 230 is determined with reference to steps S100 and S200, prioritizing the distance between the first ground via 121, the second ground via 230, and the signal via 310. Then, based on the degree of impact on channel performance, the fourth ground via 123, which has the next greatest impact, is determined. The greater the distance between the ground via 120 and the signal via 310, the smaller the impact. The centers of the first ground via 121 and the signal via 310 are aligned, ensuring that the second center-to-center spacing d2 is not greater than d1. A smaller d2 is beneficial for improving signal bandwidth. The second ground via 230 is placed close to the inner layer trace 330, maintaining a safe distance to avoid damaging the inner layer trace 330. The third center-to-center spacing d3 between the second ground via 230 and the signal via 310 is not greater than d1. Decreasing d3 improves signal bandwidth, and the proximity of the second ground via 230 to the inner layer trace 330 allows space for the third ground via 122, further refining the cavity-like structure. The third ground via 122 is centered with the nearest first ground via 121 and second ground via 230. If layout space is insufficient, the third ground via 122 can be removed, and the position of the second ground via 230 adjusted accordingly to ensure optimal coverage of the signal via 310 by the first and second ground vias 121 and 230. Furthermore, a fourth ground via 123 is placed on the ground pad 100 near the signal via 310. The fourth ground via 123 is centered with the first ground via 121 of the corresponding ground pad 100. The center-to-center distance d5 between the first ground via 121 and the fourth ground via 123 is equal to the center-to-center distance d4 between the first ground via 121 and the corresponding third ground via 122, thus refining the cavity-like structure and suppressing crosstalk between adjacent channels. The fourth ground via 123 can be arranged at equal intervals. Multiple fourth ground vias 123 can improve the resonant cavity structure and suppress crosstalk between adjacent channels. Specifically, the fourth ground via 123 can completely cover the corresponding ground pad 100, or the fourth ground via 123 and the first ground via 121 can completely cover the corresponding pad, such as... Figure 3 As shown, the local pad 100 is longer than Figure 3 The ground pad 100 shown can be used Figure 3 Based on this, a fourth ground via 123 is added so that the remaining ground pad 100 is covered by the fourth ground via 123, thereby improving the resonant cavity structure and suppressing crosstalk between adjacent channels.
[0099] The above description, with reference to the accompanying drawings, illustrates some embodiments of this application, but does not limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of this invention should be considered within the scope of this application.
Claims
1. A printed circuit board, the printed circuit board comprising: Multiple ground pads, each of which is provided with a first grounding part; At least one signal pad is located between two ground pads, and each signal pad is electrically connected to a signal via; a second ground portion is provided on the first ground portion and the first side of the signal via, and the first ground portion and the second ground portion together form a cavity-like structure that encloses the signal via.
2. The printed circuit board according to claim 1, characterized in that, The first grounding part is configured as a first ground via; the second grounding part is configured as a second ground via.
3. The printed circuit board according to claim 2, characterized in that, The signal pads are provided with at least two, and the first ground via is aligned with the center of the signal via; two adjacent signal vias located on different signal pads are aligned with the center, and the first center distance between the two aligned signal vias is greater than or equal to the second center distance, which is the center distance between the first ground via and the nearest aligned signal via.
4. The printed circuit board according to claim 3, characterized in that, The first center-to-center spacing of the two center-aligned signal vias is greater than or equal to the third center-to-center spacing, which is the center-to-center distance between the second ground via and the nearest signal via.
5. The printed circuit board according to claim 1, characterized in that, The plurality of ground pads include a first pad, and the first ground portion on the first pad is configured as a first ground via; a corresponding third ground via is provided on the first side of each first ground via, and the third ground via is aligned with the center of the corresponding first ground via; The second grounding portion is located between the third ground via and the signal via.
6. The printed circuit board according to claim 5, characterized in that, The first ground pad is also provided with at least one fourth ground via, the fourth ground vias are equally spaced on the second side of the first ground via, and the center of the fourth ground via is aligned with the center of the corresponding first ground via.
7. The printed circuit board according to claim 6, characterized in that, The distance between the third ground via and the first ground via on the same first ground pad is equal to the distance between the adjacent fourth ground via and the first ground via on the same first ground pad.
8. The printed circuit board according to claim 1, characterized in that, A third grounding portion is provided on the side of the ground pad and the signal pad away from the signal via. The third grounding portion, the first grounding portion, and the second grounding portion together form a resonant cavity-like structure that surrounds the signal via.
9. The printed circuit board according to claim 8, characterized in that, The third grounding portion is composed of multiple spaced fifth ground vias arranged in columns; the first grounding portion is configured as a first ground via; the two fifth ground vias located at the ends of the third grounding portion are respectively aligned with the center of the first ground via of a ground pad.
10. The printed circuit board according to claim 8, characterized in that, The third grounding part is configured as a first metallization groove.
11. The printed circuit board according to claim 10, characterized in that, The second grounding part is configured as a second metallization groove.
12. The printed circuit board according to claim 11, characterized in that, The first grounding part is configured as a third metallization groove, the length of the third metallization groove is greater than the corresponding ground pad, and both ends of the third metallization groove protrude from the ends of the corresponding ground pad.
13. A method for arranging vias on a printed circuit board, the method comprising: The pad size, pad spacing, and drill diameter of the signal via electrically connected to the signal pad are obtained; the signal pad is located between two adjacent ground pads, and each ground pad is connected to a first grounding part; Based on the drill hole diameter, the pad size, and the pad spacing, a first position is determined on the first side of the signal via and the first ground portion, wherein the first position is the position that has the greatest impact on the channel performance of the signal via; A second grounding portion is provided at the first position so that the first grounding portion and the second grounding portion enclose and form a cavity-like structure that surrounds the signal via.