For a USB30 hub that I'm designing with a TUSB8020B (one upstream port and two downstream ports) I've chosen to use a Type-A connector.

A first question is what model should I use, a plug or a receptacle?

To avoid any protrusion from my hub, my desire is to use a Type-A receptacle so the first question is:

  1. Is it USB compliant and correct practice use a Type-A receptacle on the upstream side of the hub? This question arise because in many commercial hubs I can see a piece of cable with a plug on the end, but in my device I'll not desire to use such solution because a simple receptacle is simpler and less costly Of course, the final user have to use an external cable to connect the hub to the PC (Type-A plug ----- Type-A plug or msle to male.)

  2. The next question is about the signals connection between the receptacle HUB and the controller that is on my PCB. Will I need to do some signal swapping between the SSRX and SSTX differential pairs?

My candidate for the receptacle connector is the WURTH code 6921220300100, here below an image:

enter image description here

From the connector datasheet we have the following signal table:

enter image description here

Now my final question. Considering the commercial cable adapter available male to male, do I have to connect the SSRX pairs from pin 5 and 6 of the connector to the same related signals on the controller or do I have to perform a cross connection to the controller SSTX pairs? Same about the SSTX pairs from pin 8 and pin 9 of the connector.


1 Answer 1

  1. Please see datasheet figure 26 to see what connectors to use.

You especially don't want a type A socket as they are reserved for the downstream ports.

And before someone mentions it in the comments, cables with type A plugs on both ends were not allowed earlier, but later standards do allow cables with type A plugs on both ends, but these cables are special and have no the standard USB data or power wires, only the SuperSpeed wires. So even if it were compliant to use Type A receptacle, it will be useless as the hub would not work as intended.

  1. Please see datasheet figures 27 and 28 how to connect the pins.
  • \$\begingroup\$ Thanks, figure 26 mention Type B, but into the example design TIDA-00287 reference design for the upstream connector is used a TYPE-A plug connector (J1), instead, as you pointed out, into the controller datasheet is written "USB3_TYPEB_CONNECTOR"... this create some confusion because seems that all the solutions provided (reference design and datasheet) can be used... so there is no way to use a receptacle TYPE-A? May be a solution use the receptacle and a male cable to simulate the plug with cable that we can see in many commercial hub? Thanks! \$\endgroup\$
    – FIRE FOX
    Oct 21, 2022 at 17:56
  • \$\begingroup\$ There is no confusion. A product is a product for customers. An eval board is maybe used by TI and other engineers that need to test and evaluate the chip how it performs, so you want to be able to plug it directly to test equipment without cables that will just disturb the measurements. But it is a valid solution as in the end the product technically has a captive cord with length of 0 and type A plug to plug it to a PC. \$\endgroup\$
    – Justme
    Oct 21, 2022 at 18:37
  • \$\begingroup\$ ok so also the plug solution is a valid standard one, thanks, I'll check for the USB TYPE-B from Amphenol GSB3211311WEU. Thanks again! \$\endgroup\$
    – FIRE FOX
    Oct 21, 2022 at 19:10

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