PCB used for BTB structure QSFP connector

Abstract

The utility model discloses a PCB used for a BTB structure QSFP connector. The PCB comprises a PCB body, a top layer QSFP interface and a bottom layer QSFP interface. The top-layer QSFP interface is installed on the upper surface of the PCB body, the bottom-layer QSFP interface is installed at the position, right facing the top-layer QSFP interface, on the lower surface of the PCB body, bonding pads of the top-layer QSFP interface and the bottom-layer QSFP interface are alternately distributed in a staggered mode in the projection direction of the PCB body, and the two interfaces are each matched with a QSFP optical module; the PCB body is of an N + N structure formed by pressing two PCB daughter boards; an electroplating through hole penetrates through the two PCB daughter boards; the two PCB daughter boards are respectively provided with a mechanical blind hole which extends from the outer layer to the pressing contact layer of the two PCB daughter boards. The mechanical blind hole is punched at the top end of a bonding pad of the PCB daughter board along the pin direction of the QSFP optical module; and high-speed signal fan-out of the top-layer QSFP interface and the bottom-layer QSFP interface is completed by the corresponding PCB daughter boards. According to the utility model, crosstalk between signals is reduced.

Description

Technical Field

[0001] This utility model relates to the field of telecommunications and data communication technology, and in particular to a PCB board for a BTB structure QSFP connector. Background Technology

[0002] A PCB, also known as a printed circuit board, provides electrical connections for electronic components. Its development has a history of over 100 years; its design primarily involves layout design. The main advantages of using PCBs are significantly reduced wiring and assembly errors, improved automation levels, and increased production efficiency. PCBs can be classified according to the number of layers: single-sided, double-sided, four-layer, six-layer, and other multi-layer circuit boards.

[0003] Most existing PCBs use only one QSFP interface, resulting in limited transmission channels and low transmission rates. There is an urgent need for a PCB with a dual-density QSFP interface to solve these problems. Utility Model Content

[0004] The purpose of this invention is to provide a PCB board for BTB structure QSFP connectors. The stack-up adopts N+N mechanical blind holes, reasonable fan-out routing design, and via model design, which not only solves the fan-out space problem and reduces crosstalk between signals, but also further improves the transmission quality of 112G PAM4 signals on the PCB board.

[0005] The technical solution adopted in this utility model is:

[0006] A PCB board for a BTB (Belly to Belly) QSFP connector includes a PCB board body, a top-level QSFP interface, and a bottom-level QSFP interface. The top-level QSFP interface is mounted on the upper surface of the PCB board body. The bottom-level QSFP interface is mounted on the lower surface of the PCB board body, corresponding to the position of the top-level QSFP interface. The pads of the top-level and bottom-level QSFP interfaces are alternately staggered in the projection direction of the PCB board body. A QSFP optical module is mounted on each of the top-level and bottom-level QSFP interfaces.

[0007] The PCB body consists of two PCB sub-boards forming an N+N structure, with the two sub-boards laminated together to form the PCB body. A plated through-hole penetrates both PCB sub-boards. Each of the two PCB sub-boards has a mechanical blind via that matches the corresponding QSFP optical module. The mechanical blind via extends from the outermost layer of the corresponding PCB sub-board towards the bonding contact layer of the two PCB sub-boards. The mechanical blind via is directly punched onto the top of the pad on the corresponding PCB sub-board according to the pin direction of the QSFP optical module. High-speed signals are connected to the pad on the PCB sub-board via the QSFP optical module pins and then directly enter the PCB. The high-speed signal fan-out of the top-layer QSFP interface and the bottom-layer QSFP interface is completed by the corresponding connected PCB sub-boards.

[0008] Furthermore, both the top-level QSFP interface and the bottom-level QSFP interface are compatible with the QSFP-112 optical module.

[0009] Furthermore, the mechanical blind holes on the two PCB sub-boards are vertically offset.

[0010] Furthermore, both PCB sub-boards are 10-layer PCB boards; each PCB sub-board uses the fifth and seventh layers in the order of relative outer layers to the lamination contact layers as high-speed routing layers, and the fourth layer as a high-speed pad reference layer.

[0011] Specifically, the high-speed signal fan-out of the top-level QSFP interface is completed by the upper layers of the PCB board, namely L1-L10, using L5 & L7 to fan out the high-speed signal. The high-speed signal fan-out of the bottom-level QSFP interface is completed by the lower layers of the PCB board, namely L11-L20, using L14 & L16 to fan out the high-speed signal. At this time, the fan-out of the BTB QSFP-112 connector does not interfere with each other, and the high-speed signal of QSFP-112 is optimally processed in the belly to belly structure.

[0012] Furthermore, the high-speed trace layer and reference layer copper foil adopt high-frequency ultra-low profile copper foil (H-VLP). Specifically, as a feasible implementation, the PCB board material adopts Panasonic M6G.

[0013] Furthermore, the QSFP optical module has an "LL" pin package.

[0014] Furthermore, the return via is located on the corresponding PCB sub-board grounding pad.

[0015] This utility model adopts the above technical solution. For the belly-to-belly structure QSFP connector, the PCB board body stack uses N+N mechanical blind holes, reasonable fan-out routing design, and via model design. This not only solves the fan-out space problem and reduces crosstalk between signals, but also further improves the transmission quality of QSFP optical module (especially 112G PAM4) signals on the PCB board. Attached Figure Description

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0017] Figure 1 This is a schematic diagram of the BTB structure QSFP connector of this utility model;

[0018] Figure 2 This is a schematic diagram of the pin structure of the QSFP optical module of this utility model;

[0019] Figure 3 This is a schematic diagram of the projection of the pads of the top-level QSFP interface and the bottom-level QSFP interface of this utility model onto the PCB board.

[0020] Figure 4 This is a schematic diagram of the through-hole and blind-hole structure on the PCB board of this utility model;

[0021] Figure 5 This is a schematic diagram of the through-hole model structure of this utility model. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0023] like Figures 1 to 5 As shown in the figure, this utility model discloses a PCB board for a BTB (Belly to Belly) structure QSFP connector, which includes a PCB board body 1, a top QSFP interface 4, and a bottom QSFP interface 5; the top QSFP interface 4 is mounted on the upper surface of the PCB board body 1; the bottom QSFP interface 5 is mounted on the lower surface of the PCB board body 1, corresponding to the position of the top QSFP interface 4; the pads of the top QSFP interface 4 and the bottom QSFP interface 5 are alternately staggered in the projection direction of the PCB board body 1; a QSFP optical module 2 is respectively mounted on the top QSFP interface 4 and the bottom QSFP interface 5.

[0024] The PCB body 1 is formed by two PCB sub-boards in an N+N structure. The two sub-boards are laminated together to form the PCB body 1. An electroplated through-hole 10 penetrates the two PCB sub-boards. The two PCB sub-boards are respectively provided with mechanical blind vias (13 and 14) that are matched with the corresponding QSFP optical module 2. The mechanical blind vias (13 and 14) extend from the opposite outer layer of the corresponding PCB sub-boards toward the lamination contact layer of the two PCB sub-boards. The mechanical blind vias are directly punched on the top of the pads of the corresponding PCB sub-boards according to the pin direction of the QSFP optical module 2. The high-speed signal is connected to the pads of the PCB sub-board through the pins of the QSFP optical module 2 and then directly enters the PCB. The high-speed signal fan-out of the top QSFP interface 4 and the bottom QSFP interface 5 is completed by the corresponding connected PCB sub-boards.

[0025] Furthermore, both the top-level QSFP interface 4 and the bottom-level QSFP interface 5 are compatible with the QSFP-112 optical module.

[0026] Furthermore, the mechanical blind holes (13 and 14) of the two PCB sub-boards are vertically offset.

[0027] Furthermore, both PCB sub-boards are 10-layer PCB boards; each PCB sub-board uses the fifth and seventh layers in the order of relative outer layers to the lamination contact layers as high-speed routing layers, and the fourth layer as a high-speed pad reference layer.

[0028] Specifically, the high-speed signal fan-out of the top-level QSFP interface 4 is completed by the upper PCB sub-board of the PCB body 1, namely L1-L10, using L5 & L7 to fan out the high-speed signal. The high-speed signal fan-out of the bottom-level QSFP interface 5 is completed by the lower PCB sub-board of the PCB body 1, namely L11-L20, using L14 & L16 to fan out the high-speed signal. At this time, the fan-out of the BTB QSFP-112 connectors does not interfere with each other, and the high-speed signal of QSFP-112 is optimally processed in the belly to belly structure.

[0029] Furthermore, the high-speed trace layer and reference layer copper foil adopt high-frequency ultra-low profile copper foil (H-VLP). Specifically, as a feasible implementation, the PCB board material adopts Panasonic M6G.

[0030] Furthermore, the pin 3 package of the QSFP optical module 2 is of the "LL" type.

[0031] Furthermore, the return ground via 15 is set on the corresponding PCB sub-board grounding pad.

[0032] The following detailed explanation uses the QSFP-112 optical module as an example:

[0033] like Figure 3As shown, the QSFP-112 connector has an "LL" pin package. After two QSFP-112 optical modules are mounted belly-to-belly on opposite sides of the board, the pad distribution on the PCB is as follows: green indicates the pad distribution of the QSFP-112 connector interface on the TOP layer, and red indicates the pad distribution of the QSFP-112 connector interface on the BOTTOM layer.

[0034] The QSFP-112 connector uses an N+N structure for high-speed signal fanout vias, meaning the PCB is processed as two separate boards: L1-L10 on one board and L11-L20 on another. The two PCBs are then laminated to form the final board. As shown in Table 1, compared to conventional through-hole stacking, this adds mechanical blind vias 13 and 14 to L1-L10 and L11-L20; and it adds electroplating processes for the inner layers L10 & L11 and L1 & L20.

[0035] Table 1 PCB Board Design Planning

[0036] Design Planning board thickness 3.0mm + / -10% number of floors 20th floor PCB board Panasonic M6G High-speed wiring layer L5 & L7 & L14 & L16 Connector high-speed pad reference layer L4 & L17 Selection of copper foil for high-speed trace layers and reference layers HVLP Treatment of residual piles in boreholes Back Diamond

[0037] Fan-out routing design: High-speed signals from the QSFP-112 connectors on the top layer are fanned out by the upper layers of the PCB, i.e., L1-L10, using L5 & L7 for high-speed signal fanning. High-speed signals from the QSFP-112 connectors on the bottom layer are fanned out by the lower layers of the PCB, i.e., L11-L20, using L14 & L16 for high-speed signal fanning. In this design, the fan-out of the BTB QSFP-112 connectors does not interfere with each other, ensuring optimal processing of the QSFP-112 high-speed signals in a belly-to-belly configuration.

[0038] Via model design: such as Figure 5 As shown in the diagram, labels 11 and 12 indicate the positions of the two rows of pins on the QSFP-112 connector on the PCB. Mechanical blind vias are placed directly at the top of the pads along the pin direction of the QSFP-112 connector. This allows high-speed signals to travel from the connector pins to the PCB pads and then directly into the PCB interior. Fan-out vias are placed directly at the top of the pads along the pin direction. This via method avoids the high-speed signal loss caused by impedance discontinuities and some drawbacks of microstrip lines when using surface fan-out traces. Furthermore, return ground vias can be placed directly on the connector's ground pad, minimizing the return path for high-speed signals.

[0039] This utility model adopts the above technical solution. For the belly to belly structure QSFP connector, the PCB board body 1 is stacked with N+N mechanical blind holes, reasonable fan-out routing design, and via model design. This not only solves the fan-out space problem and reduces crosstalk between signals, but also further improves the transmission quality of QSFP optical module 2 (especially 112G PAM4) signals on the PCB board.

[0040] Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Without conflict, the embodiments and features in the embodiments of this application can be combined with each other. The components of the embodiments of this application described and illustrated herein can generally be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A PCB board for BTB structure QSFP connectors, characterized in that: It includes a PCB board body, a top-level QSFP interface, and a bottom-level QSFP interface; the top-level QSFP interface is installed on the upper surface of the PCB board body; the bottom-level QSFP interface is installed on the lower surface of the PCB board body, corresponding to the position of the top-level QSFP interface; the pads of the top-level and bottom-level QSFP interfaces are alternately staggered in the projection direction of the PCB board body; a QSFP optical module is installed on each of the top-level and bottom-level QSFP interfaces. The PCB body consists of two PCB sub-boards forming an N+N structure, with the two sub-boards laminated together to form the PCB body. A plated through-hole penetrates both PCB sub-boards. Each of the two PCB sub-boards has a mechanical blind via that matches the corresponding QSFP optical module. The mechanical blind via extends from the outermost layer of the corresponding PCB sub-board towards the bonding contact layer of the two PCB sub-boards. The mechanical blind via is directly punched onto the top of the pad on the corresponding PCB sub-board according to the pin direction of the QSFP optical module. High-speed signals are connected to the pad on the PCB sub-board via the QSFP optical module pins and then directly enter the PCB. The high-speed signal fan-out of the top-layer QSFP interface and the bottom-layer QSFP interface is completed by the corresponding connected PCB sub-boards.

2. The PCB board for a BTB structure QSFP connector according to claim 1, characterized in that: Both the top-level QSFP interface and the bottom-level QSFP interface are compatible with the QSFP-112 optical module.

3. A PCB board for a BTB structure QSFP connector according to claim 1, characterized in that: The mechanical blind holes of the two PCB sub-boards are vertically offset.

4. A PCB board for a BTB structure QSFP connector according to claim 1, characterized in that: Both PCB sub-boards are 10-layer PCB boards; the fifth and seventh layers of each PCB sub-board are high-speed routing layers in the order from the outermost layer to the lamination contact layer, and the fourth layer is used as a high-speed pad reference layer.

5. A PCB board for a BTB structure QSFP connector according to claim 4, characterized in that: The high-speed trace layer and reference layer copper foil use high-frequency ultra-low profile copper foil.

6. A PCB board for a BTB structure QSFP connector according to claim 1, characterized in that: The QSFP optical module has an "LL" pin package.

7. A PCB board for a BTB structure QSFP connector according to claim 1, characterized in that: The return via is located on the corresponding PCB sub-board grounding pad.

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