Schematics for USB Device Only

Hi Naoki Kawada,

Thanks for the post.

Your understanding on USB0_VBUS is correct if you are configuring USB2.0 in HOST mode.

TI has the application report on USB compliance testing. Please find those application reports from below links.

http://www.ti.com/lit/an/sprab51/sprab51.pdf

http://www.ti.com/lit/an/sprab50/sprab50.pdf

Hi Naoki Kawada,

Please refer the OMAP-L13x/C674x/AM1x Schematic Review Checklist.

http://processors.wiki.ti.com/index.php/OMAP-L13x_/_C674x_/_AM1x_Schematic_Review_Checklist#USB0_.28USB_2.0_OTG.29

Thanks.

Hi Rajasekaran K,

Thank you for your reply and useful links!
I suggested the same to my customer.

Lastly, let me confirm one thing.
My customer needs a brief clarification about HW connection for "Device Compliance Testing".

http://www.ti.com/lit/an/sprab51/sprab51.pdf

In this document, the test looks like passing correctly, but there is no information about HW connection for the test case.
Can I understand this application report was documented with the HW connection which UG is suggesting (local 5V connection for USB0_VBUS) ? 

Best Regards,
Kawada 

Hi Kawada,

I hope, you have referred the shared wiki link. 

For USB2.0 device mode of operation, USB0_VBUS should be connected to connector. (not to local 5V)

For USB2.0 host mode of operation, USB0_VBUS should be connected to Power supply & connector.

Thanks.

Hi Rajasekaran K,

Yes, I've confirmed the link. Unfortunately It confused me about the connection again.
UG says that local 5V can be used, but wiki says external VBUS should be used.
Which connection is more preferred for USB device only function ? 

For me, I still think local 5V should be preferred.
Please consider about the use case which USB host is connected to USB device without the power on IOs/Core power lane.
In this case, USB0_VBUS would be powered via USB connector without the power on IOs/Core.
I think this is not preferred in the electrical point of view.

Also, please refer to the following post:
http://e2e.ti.com/support/dsp/omap_applications_processors/f/42/t/91701.aspx
This also says that local 5V should be used.
What do you think of this ? 
I need the answer for this and the information about actual HW connection TI tested for "Device Compliance Testing".

Best Regards,
Kawada 

Hi David,

Thank you for your reply.
I understood the signal integrity would be same between local 5V and external 5V use cases.
As you suggested,  my customer started to consider about external 5V with load switch.

Best Regards,
Kawada