So I've been getting into the world of USB C and was wondering how hard it'd be to create a USB hub that supports the USB Alt mode for things like video. I've noticed there are USB-A hubs on eBay for very cheap, but I couldn't find anything like that for USB type C. I feel like it'd be pretty fun and cool to create my own and I think it could be significantly cheaper than some of the ones out there... Thanks!

Also Sorry if this has been asked before!


3 Answers 3


USBC is somewhat difficult for a beginner,

  • The connector pins are so dense, so you need to pay for thinner traces than the cheaper boards to escape them from the connector.
  • 4 Layers at a minimum due to the speeds of the signals, and controlling for the correct impedance and length is much harder than for the usual USB 2.0
  • The hub controller IC's in almost all cases will be a dense BGA package, which most beginners really do not like dealing with, this may also force your layer count up, as escaping impedance controller differential pins from that BGA may not be possible with only 4 layers.

If that has not scared you off, pull up the datasheet for a USBC hub controller that covers the feature set your after and have fun. the better you control the impedance and length of the differential pairs, the better your product will be.

If such a controller does not exist, then things are much harder, and may involve burying yourself under a few hundred / thousand pages of specifications to implement in an FPGA

  • 1
    \$\begingroup\$ Thanks, but I think you scared me off! I can't find a premade board so don't think I'm going to follow through lol. \$\endgroup\$
    – S1ant
    May 16, 2020 at 5:14

and was wondering how hard it'd be to create a USB hub that supports the USB Alt mode for things like video.

This is not about how dense a Type-C connector is, or how many layers of PCB one needs to use to make compact differential traces. Or how dense the hub controller pinout is (it is usually QFN, not BGA). And the question is not even how hard it is to design a silicon chip that will incorporate logic and datapath for at least three hubs (USB2, USB3, and DP), it usually takes several dozens of men-years of seasoned engineering teams (an this is no fun). The question is how soon it will be economically beneficial to have this kind of device on your desk.

USB hubs a relatively cheap because the industry is producing them (and people use them) in quantities of maybe 100,000,000 units per year.

As a matter of fact, the device you want to make for a fun is called USB4.

If you can justify a business plan to make this kind of IC and can afford to spend $10-$20M plus years for PC host controllers to catch-up, and software stack to become functional within Microsoft windows, and have full-featured 10-GHz low loss cables at your disposal, then you can have all the fun you want.


What you are trying to achieve is possible. You could use cheap ICs for the features you need. For DP alt mode there's VL102-Q4 and I think VL817 USB hub IC. If you also need to charge through the hub then also get a DRP IC. It's a bit of work, but what isn't. I'm not saying it's easy but I think it'll be worth it. I'm also working on something similar.


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