Part Number: TUSB8041
Hello team,
The following events have occurred in my customer's test of TUSB8041IRGCR:
- Symptom: Does not recognize as a USB3.0 hub at startup, but is recognized as a USB2.0 hub. (Only USB2.0 hubs appear in Windows Device Manager)
After reset and setting GRSTz to Lo, but it does not recognize it correctly. (Reconnected as a USB2.0 hub)
- Frequency: Sometimes at high temperatures (70°C) (about once every 100 cycles)
- With individual differences (only 2 out of 7)
It is known to be affected by the power sequence. (See attachment)
The VDD1.1V is generated from VDD3.3V, but the 3.3-V rise rate is slow and the power supply rising waveform became as picture shown in the attached file.
After delaying VDD1.1V startup, this phenomenon no longer occurs.
(GRSTz is externally controlled at startup, and reset is released more than 3ms after 3.3 V is up.)
We think that if GRSTz was controlled properly from the outside, the VDD1.1V and VDD3.3V sequences were not necessary.
Is there any problem with the attached rising waveform?
Best Regards,
Ryotaro Fukui
