I'm designing a custom hot swap connector with pogo pin contacts, similar to that of an electronic camera lens. I am wondering if there are any special considerations I should be taking if I want to implement ethernet across these pins: I plan to have a hot-swap controller for protection, but is there anything I should be weary of in terms of noise, routing, shielding etc?
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\$\begingroup\$ Biggest question is the matched impedance of the Ethernet lines. All the data lines are supposed to be 100Ohm impedance matched. I don't see how you can do that with pogo pins. \$\endgroup\$– PuffafishCommented Sep 24, 2020 at 11:36
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\$\begingroup\$ @Puffafish 50 Ohms differential 100 Ohms single ended is the correct answer \$\endgroup\$– schnedanCommented Sep 24, 2020 at 11:46
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\$\begingroup\$ I would try hard to put the ethernet on one side or the other, rather than including the connection. I can't immediately envision a case where the latter is necessary. \$\endgroup\$– Scott SeidmanCommented Sep 24, 2020 at 11:49
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\$\begingroup\$ @schnedan Are you sure it isn't 100 ohms differential and 50 ohms single-ended? rayan4444 Which kind of ethernet specifically, and would this just replace a 8P8C connector? Or will this be for MII? \$\endgroup\$– JustmeCommented Sep 24, 2020 at 12:03
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\$\begingroup\$ @Justme of course you I right, I reversed it... \$\endgroup\$– schnedanCommented Sep 24, 2020 at 12:14
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should I be weary of in terms of noise, routing, shielding etc
Of course.
So best thing is, after you done the theoretical calculations test your design with an FEM field simulation...
Edit: let me state it this way: We did the development of an Ethernet capable connector in my company, Took us many month of work, simulating, measurement, etc... You need profound knowledge of the standards, top equipment like a NWA, FEM based simulations, etc... This is far beyond such a simple question... In fact the question alone shows the lack of qualification for that task. Its not I want to be mean, but realistic
Edit2:
Just to provide some more usefull information, HF-Connectors are very much defined by geometrical layout, so you need first to draw what layout in 3 dimensions the connector should have. then placement, shape, order of signal contacts is essential. From that its a lot of fine tuning if the general layout is OK. As the HF wave travels not though the conductor but the isolation material, the permittivity of material mix must be considered. step changes in permittivity or geometrical dimensions results in reflections. Wrong placement,order,shape of contacts will result in poor NEXT and or TCL performance....
