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I will need to connect several PCBs within a single enclosure for the project I am working on (They are split to reduce cost should there be a manufacturing error).

I need to connect an I2C Bus, 5V , an analogue and 3 digital signals (and importantly, the ground plane) from each 'slave' board to the master.

Is there a universal connector that would be appropriate for all of these signals? I am also under the impression that I want as 'wide' a connection for the ground planes as possible (Multiple connection points?) to reduce RF emissions?

to clarify: all of the digital signals are 5V logic, either from a PSOC, arduino or a CMOS chip. The analogue signal is 0-5V. Signal integrity of the analogue line is a priority as I cannot connect the external reference signal to the line due to pin restrictions and am relying on an internal reference.

The PCBs are 35mm Wide (Though I will take them down to an inch if I can manage), will be placed basically touching each other, and arranged like this:

. _____________________
|######MASTER#### |
|____________________
| # S # |# S # | # S # |
| # L # |# L # | # L # |
| # A # |# A # | # A # |
| # V # |# V # | # V # |
| # E # |# E # | # E # |
| # # # |# # # | # # # |
|______|______|______|

Sorry for the bad ascii art, I made bad paint art but couldnt attach it.

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closed as too broad by Chris Stratton, RoyC, laptop2d, Sparky256, PeterJ Mar 14 '18 at 13:52

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ There are many - open any catalog. This is both far too broad, and a "shopping question". \$\endgroup\$ – Chris Stratton Mar 6 '18 at 16:30
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    \$\begingroup\$ I think you should narrow down your question by saying what are the characteristics you require. Flexible connection? Rigid connection? How much current? What are the bandwidths included (you need a 2GHz connection or even the usual 100mils connectors are fine)? How much you want to spend? \$\endgroup\$ – frarugi87 Mar 6 '18 at 16:32
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    \$\begingroup\$ Probably the easiest is ribbon cable since the connectors are super cheap, readily available, and easy to assemble. But depending on your other requirements, there are literally thousands of options. \$\endgroup\$ – Selvek Mar 6 '18 at 16:35
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    \$\begingroup\$ "from each 'slave' board " How many boards are you connecting? What is the mechanical positioning relative to each other? What are the distances involved? Have you considered a "back-plane" design? \$\endgroup\$ – Trevor_G Mar 6 '18 at 16:49
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    \$\begingroup\$ How much current do you expect to see on the 5V rail (maximum)? That will determine the number of pins for power; I normally use that number plus a couple for grounds. \$\endgroup\$ – Peter Smith Mar 6 '18 at 16:52
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I would use standard 2.56 pitched pin rows. Preferably gold coated. Either vertical or at 90 degree, according to the most rational set up geometricaly. For even better contact, look for gold fingers.

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Given this reasoning:

(They are split to reduce cost should there be a manufacturing error)

Solder wires between them. You don't really need a connector, if you are not really making something with subsystems that are removed and replaced, and connectors are both expensive and prone to issues with connection quality. If you decide after assembly that there was an error and something needs to be replaced, clip the wires, remove the board, unsolder the wire stubs, and wire in a new board.

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    \$\begingroup\$ No. Soldering wires is quite expensive. It does not automate anywhere near as well as soldering connectors does. \$\endgroup\$ – Chris Stratton Mar 7 '18 at 2:19
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    \$\begingroup\$ If you're at the point of automated assembly, you make sure there are no production errors and make one board, with no connectors. \$\endgroup\$ – Ecnerwal Mar 7 '18 at 3:18
  • \$\begingroup\$ Well part of the reasoning for splitting them is for cheaper repairs under warranty, allowing the failed board section to simply be swapped out. I'm not keen on adding manual soldering tasks to what will otherwise be automated assembly. \$\endgroup\$ – GigaJoules Mar 7 '18 at 13:53
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    \$\begingroup\$ This was not mentioned in your question. When you conceal information, you get answers based on the information your choose to reveal. Please don't make it an Easter Egg Hunt to figure out what in heck your ACTUAL reasons for doing things are. \$\endgroup\$ – Ecnerwal Mar 7 '18 at 14:02
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If you are not doing anything high speed (e.g. I2C is the fastest relevant signal) I suggest something like short 2mm ribbon cables. Pre-made IDC ribbon cables are durable and don't place a lot of strain on the connector when you have them hanging around without a bespoke mechanical enclosure.

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This is quite an open-ended question but something to consider is whether you want a rigid or flexible connection. I usually opt for a flexible connection using wiring terminated by a JST connector of some type.

JST homepage listing their various options

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  • \$\begingroup\$ Would there be any significant advantages for a solid connection? \$\endgroup\$ – GigaJoules Mar 7 '18 at 13:50
  • \$\begingroup\$ Not particularly, the only time I'd specifically opt for a solid connection is when dealing with high-frequency signals. Wiring usually allows for more flexible design and assembly with regards to enlosures, especially with limited space. \$\endgroup\$ – danielwbbr Mar 8 '18 at 5:56

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