We're using this USB hub in a design where the upstream port is tied directly to a CY8C4248 PSoC controller's downstream ports on the same board. The Upstream port on the hub is getting damaged in units in the field. I've scoped the USB pins at boot and there's nothing unusual happening there, except on faulty units the DM lines stays low and the DP line goes high. So far we're looking at about a 1 percent fail rate over time, and I'm concerned it will get worse. Replacing the hub always seems to resolve things.
The VDD1.1 is delivered by an LDO tied to the VDD3.3. GRST has a 10uF to GND and a 10K to VDD3.3. Seems to meet all power up timing requirements as the voltage rails are within 3mS of each other. Any insight here?
This is the startup waveform of the upstream ports. Green is DP and yellow is DM
