Miniaturization has made alignment of multiple connectors more difficult, and the pursuit of optimal design practices and early communication with connector providers help ensure successful design.

　　What RenhotecIC need is clear and clear guidelines to understand how to deal with these alignment challenges without sacrificing system performance, density and reliability, while meeting increasingly stringent budget and listing time requirements.     Before describing the conflicting requirements that may be encountered between advanced PCB and more reliable high-density connectors, this paper discusses the alignment challenges in more detail, so that these requirements can be efficiently met by using design best practices.


　　PCB board has many directions that can be improved, including density, higher data rate, thermal management, and reliability. however, these improvements are accompanied by the pressure on designers from the trend of miniaturization in terms of connector selection and implementation, especially by pairing multiple connectors onto PCB boards.

　　The application of a single paired connector group will not be problematic: because there is no tolerance accumulation, sandwich cards are assumed to float freely, and the overall and local alignment function of the connector will ensure perfect alignment.


　　However, adding more pairs of connectors in any direction and at any distance to the same master clip will introduce some cumulative tolerances. These tolerances are particularly important for PCB processing workshops, electronic manufacturing services, and properties of materials used in PCB boards.

　　To illustrate this issue, consider using a multi-layered connector system. The assembly consists of six or more components: motherboard (A), sandwich card (B), female head connector #1(C), paired with paired male head connector #1(D), female head connector #2(E) paired with male head connector #2(F).


　　The infinite number of connectors can be successfully deployed between two PCB plates if sandwich connectors and sufficiently rigid PCB plates can be manufactured, processed and assembled precisely according to nominal conditions; in fact, the variability of tolerances and material properties is a limiting or determining factor. where shown in figure 2, the designer needs to consider and state the tolerances of all components, including (A) and (B) two PCB plates that are often ignored but related.

　　How to solve the problem of PCB board to connector alignment

　　Procurement of certain PCB boards is controlled only by specifications embedded in Gerber packets. PCB boards can be built through these packets without considering mechanical tolerances.

　　For multi-connector applications, this packet must be accompanied by separate mechanical drawings to indicate original drawings, boreholes and wiring tolerances.

　　At this point, designers need to do two things to help ensure a successful outcome. first is to understand what support PCB board supplier and connector supplier can provide to ensure alignment. The second is to ensure that system-level tolerances have been studied to determine the connector alignment deviation generated by its design.

　　Multi-connector sandwich card system consisting of A to F components, connector supplier can only control the tolerance of connector. A good supplier will meet or exceed the published performance specifications, propose PCB board tolerances and processing suggestions, and even provide reference advice to recommended PCB suppliers and equipment as needed.

　　The system or product designer shall refer to the occupation dimensions and product specifications of the connectors. the alignment deviation specifications contained in these documents should be compared with the results of the system level tolerance study to help ensure that multiple connectors between the same boards are used successfully.

　　As long as the initial and final angles and linear alignment deviations are not exceeded, the connector system can run normally. these alignment deviation values are calculated by considering factors such as insulator interference, beam deflection, and contact friction. exceeding the alignment deviation value may cause circuit and/or insulator to break or damage.

　　Positioning pins are not suitable for multi-connector applications

　　Some connector manufacturers provide optional positioning pins that are typically located on the opposite side of the bottom of the connector. these positioning pins help to be placed manually and can be used to help the connector determine direction on the PCB board, and for single connector applications they do not increase overall tolerance accumulation.


　　Fix PCB plate with fastening screws

　　Some particularly sturdy applications may require the use of fastening screws to protect both PCB plates. In this case, the screws should be as close as possible to the connector system


　　Conclusion

　　Although the miniaturization trend makes it more challenging, it is still possible to use multiple connector groups on two PCB boards by using best design practices. these measures include conducting a system tolerance study to determine the connector alignment deviation, then following the connector provider's recommended occupancy dimensions and die design, and using machines to place components.

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