I'm struggling with making a USB3 connection work. The PCB needs two USB3-A female receptacle, to play sort of a "man-in-the-middle" role.
I cannot provide much detail, since it is part of an ongoing research project --- however, I boiled down the issue to a minimal PCB that we actually manufactured (as a debugging test). Here's the layout, designed with gEDA PCB:
The thin traces are 12mil wide, the thick VBUS and GND traces are 35mil wide. The through-hole connections for the receptacles' pins have a hole diameter of 28mil (minus the plating thickness), and a pad diameter of 43mil.
The idea is that I connect from the PC to this board with a male-male extension cable, and then connect the device from the other receptacle on this board (using the same cable I would use to connect the device directly from the PC). The receptacle I used is the Amphenol 10117835-002LF.
The board was manufactured with "High Frequency" material, at 1mm thickness (the "Advanced PCB" option at Seeed Studio). However, one detail is that I did not manufacture with impedance control (nor did I do any calculations of trace impedances --- on the one hand, I didn't think it would be necessary --- at this point in time I'm not sure whether it is; and on the other hand, the receptacle specifications do not include characteristic impedance).
The trouble I'm having is: it works intermittently; or maybe I should say unreliably. I'm testing with a USB3 logic analyzer we have, and that one seems to work well (I set up capture at the highest rate the device supports, and it does capture, without reporting any errors). However, I try with a USB3 camera, and that one works some times, it report errors some times, the camera freezes once in a while, etc.
Any ideas on what I did wrong (specifically, things that could explain the unreliability), or suggestions to make it work more reliably?