Non-welding replacement design method for high-speed and high-density electric connector based on fuzz button

Abstract

The invention discloses a non-welding replacement design method for a high-speed and high-density electric connector based on fuzz buttons. According to the invention, the specification and dimension of the fuzz button contact element are restrained, the PCB design requirement is adjusted, the high-speed interconnection contact stability of the fuzz button connector between parallel plates is improved, and the high-speed interconnection contact stability of the fuzz button connector between the parallel plates is improved. Further, the fuzz button microwave characteristic advantage is utilized, the rate upper limit of electrical signal interconnection between the parallel plates is improved, and the method has non-negligible value and application prospect for further improving the operational capability of aviation equipment.

Description

Technical Field

[0001] The invention relates to the technical field of interconnection between printed circuit boards, and relates to a non-welding replacement design method for a high-speed and high-density electrical connector based on a wool button. Background Art

[0002] In the current era when the basic electronic design process of avionics equipment has been greatly improved, the iteration cycle has also been greatly reduced. The frequency of improving aviation combat capabilities by partially updating components and adjusting design solutions is constantly increasing, which requires product design units to have the ability to respond quickly to needs and flexibly combine design integration. In this environment, the model of modularizing functions and splitting sub-cards, using standardized interfaces, and building functional products in a way similar to building blocks through rapid assembly methods has gradually become the mainstream practice in the market. Using parallel board electrical connectors, segmented independent functional sub-cards can be cascaded and assembled to achieve functional integration. BGA welding technology increases the speed and density of electrical connectors to the 10Gbps rate level. However, electrical connectors have the disadvantages of high welding difficulty, insufficient upper limit of speed, and inconvenient replacement.

[0003] As a new type of electrical interconnection method, fur buttons are widely used in the radio frequency field. The current technical situation of increasingly higher requirements for electrical signal transmission rates makes it impossible for traditional overlapping and plug-in electrical connectors to meet the microwave characteristics requirements of high-speed signal transmission or cascaded high-speed signal transmission. With its natural microwave characteristics, fur buttons can be reasonably used in the field of electrical signal transmission to greatly increase the upper limit of the signal rate of electrical signal transmission. As a non-welding elastic contact method, contact reliability and contact stability become inevitable design problems under high-density layout. Summary of the invention

[0004] The purpose of the invention is to provide a non-welding replacement design method for a high-speed, high-density electrical connector based on a wool button, and to replace a high-speed, high-density electrical connector with a solder connection in situ with a wool button connector with a surface contact and solderless connection. The invention improves the contact stability of the wool button connector in high-speed interconnection between parallel plates by restricting the specifications and dimensions of the wool button contact and adjusting the PCB design requirements, and then utilizes the advantages of the microwave characteristics of the wool button to increase the upper limit of the rate of electrical signal interconnection between parallel plates, which has considerable value and application prospects for further improving the combat capability of aviation equipment.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A non-welding alternative design method for a high-speed and high-density electrical connector based on a fur button, comprising any three or more of the following designs;

[0007] Design 1. The main body diameter of the hair button contact is 0.5 mm to 0.64 mm to ensure that the design impedance and loss are within a reasonable range.

[0008] Design 2: Wear-resistant metal protective caps are added at both ends of the fur button contact to ensure the strength of the contact point and reduce wear.

[0009] Design 3: The length of the button contact in the fully compressed state is no more than 80% of the static length to ensure stable contact.

[0010] Design 4: The distance between the center points of adjacent contacts of the insulation structure of the fur button connector is 1.27 mm to ensure that the impedance design requirements are met.

[0011] Design 5: The thickness of the insulation structure of the button connector should not be greater than the length of the button contact in the fully compressed state to ensure stable contact.

[0012] Design 6. The insulation structure of the button connector uses the positioning column of the replaced target connector and the locking structure required by the relevant connector standards to design a positioning and locking structure.

[0013] Design 7. The minimum diameter of the surface pad on the printed circuit board connected to the fur button connector is not less than 0.65 mm, and the maximum diameter is not more than 0.75 mm, to ensure that the impedance change is within a reasonable range while the contact is reliable.

[0014] Design 8. Perform solder mask window treatment on the overall coverage area of ​​the button connector on the surface of the printed circuit board to ensure that the device contact tends to be flat on the surface.

[0015] Design 9. A hole-in-the-pad design is made in the surface pad connected to the button connector on the printed circuit board. The minimum diameter of the hole-in-the-pad is not less than 0.2 mm and the maximum diameter is not more than 0.35 mm to ensure that the design impedance and loss are within a reasonable range.

[0016] Design 12. The surface pads connecting the printed circuit board and the fur button connector are plated with hard gold, and the gold thickness is required to be no less than 0.762 microns; or the surface pads connecting the printed circuit board and the fur button connector are treated with a surface nickel-palladium-gold process, and the nickel deposition thickness is required to be 3 microns to 8 microns, the palladium deposition thickness is 0.075 microns to 0.3 microns, and the gold deposition thickness is 0.05 microns to 0.2 microns, so as to ensure the contact strength of the printed circuit board contact surface and reduce wear.

[0017] Preferably, in Design 2, the contact end surface of the metal protective cap and the printed circuit board is circular with a diameter not less than 0.1 mm.

[0018] Preferably, in Design 3, it is also required that the elastic stress of the wool button contact piece is not greater than 0.5 Newton when in a fully compressed state, so as to ensure that the comprehensive contact stress is within a reasonable range.

[0019] Preferably, based on Design 9, it also includes:

[0020] Design 10: The holes in the disk are plugged with resin to ensure processing strength.

[0021] Preferably, based on Design 9, it also includes:

[0022] Design 11. Copper is applied to the surface of the hole in the pad, and the copper is applied to completely cover the hole in the pad and the surface of the contact pad to ensure the pad is flat.

[0023] The beneficial effects of the present invention are:

[0024] The present invention improves the contact stability of the high-speed interconnection between parallel plates by restricting the model specifications of the fur button and adjusting the PCB design requirements, reduces the microwave characteristic loss during the cascade transfer process, and improves the traditional BGA welding high-speed and high-density connection method as follows:

[0025] 1. Increase the interconnection rate between parallel boards to 20Gbps, and enable multi-level cascading;

[0026] 2. Limit the impedance change at the contact impedance mutation point to within 10%;

[0027] 3. No welding is required, interconnection is achieved through elastic contact, which improves replacement flexibility and reduces processing difficulty;

[0028] 4. Use the locking structure and positioning structure in the relevant design standards of welding connectors to design a locking structure suitable for the hair button. Without changing the application environment, it can solve the design requirements of hair button connector positioning, pressing and fastening, and pass the vibration level test within 10G.

[0029] The present invention subversively introduces the button connection method widely used in the radio frequency field into the traditional electrical signal field, improving the microwave performance and impedance stability of the electrical signal transmission process of the parallel plate interconnection; simplifies the complex BGA welding assembly method into a press-fit splicing method with elastic contact, ensuring contact stability while reducing assembly difficulty; without changing the PCB packaging form, by fine-tuning the PCB design requirements, the BGA electrical connector can be replaced in situ. It has considerable value and application prospects for further improving the combat capability of aviation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an example diagram of the key points of a non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button as shown in an embodiment. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] The non-welding alternative design method for a high-speed and high-density electrical connector based on a fur button shown in this embodiment involves three aspects: a fur button contact specification design method, a fur button connector insulation structure design method, and a printed circuit board improvement design method.

[0033] The method for designing specifications of the wool button contact comprises a method for designing the diameter of the main body of the wool button contact, a method for designing the size of the contact end surface of the wool button contact, and a method for designing the elastic compression amount of the wool button contact.

[0034] See Figure 1 As shown in the mark 1, the method for designing the main body diameter of the button contact requires that the main body diameter of the button contact should be maintained at 0.5 mm to 0.64 mm to maintain the impedance design requirement of 85 ohms to 100 ohms. In this embodiment, the main body diameter of the button contact is 0.5 mm to ensure that the impedance is matched to the design requirement of differential 100 ohms.

[0035] See Figure 1 As shown in the mark 2, the method for designing the contact end face size of the button contact piece requires that wear-resistant metal protective caps be added to both ends of the button contact piece; the contact end face of the metal protective cap and the printed circuit board is a circle with a diameter of not less than 0.1 mm. In this embodiment, a metal protective cap with a contact surface diameter of 0.1 mm is used to ensure sufficient contact area.

[0036] See Figure 1 As shown in the mark 3, the design method of elastic compression of the hair button contact requires that the length of the hair button contact in the fully compressed state is not greater than 80% of the static length, that is, the compression is not less than 20% of the static length; and requires that the hair button contact in this fully compressed state has an elastic stress of no more than 0.5 N. In this embodiment, a hair button contact with an overall compression of 20% and an elastic stress of 0.5 N is used to ensure good contact under elastic stress.

[0037] The method for designing the insulation structure of the fur button connector includes a method for designing the spacing between fur button embedding grooves, a method for designing the thickness of the insulation structure, and a method for designing the positioning and locking of the insulation structure.

[0038] See Figure 1 As shown in the mark 4, the method for designing the spacing between the fur button grooves requires that the distance between the center points of adjacent contacts of the fur button connector insulation structure be 1.27 mm.

[0039] See Figure 1 As shown in the mark 5, the insulation structure thickness design method requires that the thickness of the insulation structure of the button connector should not be greater than the length of the button contact in a fully compressed state. This embodiment uses an insulation structure with a thickness of 7 mm.

[0040] See Figure 1 As shown in the mark 6, the insulating structure positioning and locking design method requires that the insulating structure of the button connector utilizes the positioning column of the replaced target connector and the locking structure required by the relevant connector standard to design the positioning and locking structure. In this embodiment, a positioning and fastening stud with a diameter of 1.2 mm and a length of 4 mm is designed on the insulating structure of the button connector. The stud penetrates the positioning column on the printed circuit board used to position the original high-speed and high-density connector, and is fastened with a nut on the other side of the printed circuit board to fix the button connector and the printed circuit board.

[0041] The improved design method of the printed circuit board comprises a design method for the size of the contact pad of the printed circuit board, a design method for opening a window in the solder mask layer of the printed circuit board, a design method for a hole in the contact pad of the printed circuit board, a design method for plugging the via hole of the printed circuit board, a design method for copper coating on the surface of the contact pad of the printed circuit board, and a design method for gold plating on the surface of the contact pad of the printed circuit board.

[0042] See Figure 1 As shown in the mark 7, the printed circuit board contact pad size design method requires that the minimum diameter of the surface pad connected to the button connector on the printed circuit board is not less than 0.65 mm and the maximum diameter is not more than 0.75 mm. In this embodiment, a surface pad with a diameter of 0.65 mm is used to ensure sufficient contact area.

[0043] See Figure 1 As shown in the mark 8, the printed circuit board solder mask window design method requires that the solder mask window treatment be performed on the entire covered area of ​​the printed circuit board surface covered by the fur button connector, and the entire area is not allowed to be covered by the solder mask layer. Figure 1 Label 8 indicates a target physical example of the printed circuit board solder mask window design method.

[0044] See Figure 1 As shown in the mark 9, the printed circuit board contact pad hole design method requires that a hole be designed in the surface pad connected to the button connector on the printed circuit board, and the minimum diameter of the hole is not less than 0.2 mm and the maximum diameter is not more than 0.35 mm. In this embodiment, the hole design method with a diameter of 0.2 mm is adopted.

[0045] See Figure 1 As shown in the mark 10, the printed circuit board via plugging design method requires that the via in the disk in the above design requirements be plugged with resin.

[0046] See Figure 1 As shown in the mark 11, the surface copper cladding design method for the contact pad of the printed circuit board requires the surface copper cladding design for the hole in the pad in the above design requirements, and the copper cladding should completely cover the hole in the pad and the surface of the contact pad to ensure the flatness of the pad.

[0047] See Figure 1 As shown in the mark 12, the design method for hard gold plating on the surface of the contact pad of the printed circuit board requires that the surface pads connecting the printed circuit board and the fur button connector be plated with hard gold, and the gold thickness is required to be not less than 0.762 microns; or the surface pads connecting the printed circuit board and the fur button connector are treated with a surface nickel-palladium-gold process, and the nickel deposition thickness is required to be 3 microns to 8 microns, the palladium deposition thickness is 0.075 microns to 0.3 microns, and the gold deposition thickness is 0.05 microns to 0.2 microns.

[0048] The above are all the design method requirements of the present invention. The comprehensive application of all the design requirements can achieve the design objectives of improving the contact stability of the button connector and improving the high-speed interconnect signal transmission rate between parallel plates. Using more than three design methods alone to achieve part of the design objectives should be included in the protection scope of the present invention.

Claims

1. A non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button, characterized in that Contains any three or more of the following designs; Design 1, the diameter of the fur button contact body is 0.5 mm to 0.64 mm; Design 2: Add wear-resistant metal protective caps at both ends of the fur button contact; Design 3: The length of the fur button contact in the fully compressed state is not greater than 80% of the static length; Design 4, the distance between the center points of adjacent contacts of the insulation structure of the fur button connector is 1.27 mm; Design 5: The thickness of the insulation structure of the button connector is not greater than the length of the button contact in the fully compressed state; Design 6. The insulation structure of the button connector uses the positioning column of the replaced target connector and the locking structure required by the relevant connector standards to design the positioning and locking structure; Design 7. The minimum diameter of the surface pad on the printed circuit board connected to the button connector is not less than 0.65 mm and the maximum diameter is not more than 0.75 mm; Design 8. Perform solder mask window treatment on the overall coverage area of ​​the button connector on the surface of the printed circuit board; Design 9. A hole-in-the-plate design is made in the surface pad connected to the button connector on the printed circuit board. The minimum diameter of the hole-in-the-plate is not less than 0.2 mm and the maximum diameter is not more than 0.35 mm; Design 12. The surface pads connecting the printed circuit board and the fur button connector are plated with hard gold, and the gold thickness is required to be not less than 0.762 microns; or the surface pads connecting the printed circuit board and the fur button connector are treated with a surface nickel-palladium-gold process, and the nickel deposition thickness is required to be 3 microns to 8 microns, the palladium deposition thickness is 0.075 microns to 0.3 microns, and the gold deposition thickness is 0.05 microns to 0.2 microns.

2. According to claim 1, a non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button is characterized in that In Design 2, the contact end surface of the metal protective cap and the printed circuit board is circular with a diameter of not less than 0.1 mm.

3. A non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button according to claim 1, characterized in that In Design 3, it is also required that the elastic stress of the hair button contact is not greater than 0.5 Newton when in a fully compressed state.

4. A non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button according to claim 1, characterized in that Based on design 9, it also includes: Design 10: Plug the holes in the disk with resin.

5. A non-welding alternative design method for a high-speed and high-density electrical connector based on a wool button according to claim 1, characterized in that Based on design 9, it also includes: Design 11. Copper is coated on the surface of the hole in the pad, and the copper completely covers the hole in the pad and the surface of the contact pad to ensure that the pad is flat.

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