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USB Superspeed Peripherals

New Contributor

! !Hello,

We have a design with the CYUSB3304-68LTXC

We took the design from the Evaluation board and we used it with Nvidia TX2I processor , we built 2 prototypes and the boards worked properly with all 4 ports including the USB3.0 and we went to pre-production of 25 boards and now we are noticing some of the board don't have the downstream on any of the port.

We can see The Suspend LED is On, until Linux boot and it  turned Off

In Linux we can see the Hub but No other USB port  are seen

We know the Chip is Alive

Power_en is never Low ( No attempt) Always High

No Over Current ,  High

Vbus is Off

We have 26.04MHZ

Reset is High

Mode Select to Default 11 (Default No Eprom)

we have 1.2V OK

Could you tell me what could prevent the Chip from Enabling the Power Switch to provide Vbus?

I attached the schematic for  review.


1 Solution


-Please check the bulk and decoupling capacitors on VDD_IO and AVDD12_x pins from Table 3 in the Application Note

-Please add a bulk capacitor of 1uF on VBUS on US port and 150uF on VBUS in the DS ports to maintain stable voltage under maximum load condition.

- When you saw PWR_EN pulsing initially, did you see the same behavior on VBUS on the downstream ports?

-Could you please connect the hub to a Windows host and check if the issue persists?

-Currently, is the PWR_EN staying high all the time while OVRCURR also stays high when measured on the hub pins? Please send us the screenshot of the waveforms if possible.

Best Regards,


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