How to handle DVDD_USB of CC2540 is not using USB i/f?

Scott Brenneman

Other Parts Discussed in Thread: CC2540

We are not using the USB interface of the CC2540. The KeyFob reference design, which doesn't use it either, leaves the DVDD_USB and DGND_USB pins unconnected. The datasheet and User Guide don't address this, but I'm nervous about leaving power and ground pins unconnected. Can I trust the reference design and leave those pins open?

Thanks,

Scott

over 11 years ago

0 Eirik V over 11 years ago

TI__Guru 56590 points

You can ground all the USB related pins (DVDD_USB, DGND_USB, USB_P, USB_N) like it is done in the CC2540EM reference design.

0 Scott Brenneman over 11 years ago in reply to Eirik V

Genius 3295 points

It's odd that one reference design grounds them while another floats them. How do we know which reference design is correct, or are both correct?

Thanks,

Scott

0 Eirik V over 11 years ago in reply to Scott Brenneman

TI__Guru 56590 points

For current consumption you shouldn't see a difference and for operation either is fine, but grounding is probably the safest way to go. Just make sure that the USB interface is never activated by the software.

0 Scott Brenneman over 11 years ago in reply to Eirik V

Genius 3295 points

Okay, thanks!

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How to handle DVDD_USB of CC2540 is not using USB i/f?