USB jac grounding and USB measurement
 

Hi guys.

I have made a USB DAC using the TI PCM2702 IC with great results. However, I haven't ever grounded the shield, just the ground pin. In case I am not being clear, I have the the mounting tabs of the USB jack floating. Should it be grounded? Or perhaps grounded through a bead? Thank you.

While I'm on the subject, does anyone have ideas of how to get measurement signals, specifically an Audio Precision output, in USB format so I can measure the DAC's performance?

I notice it isn't grounded on the TI reference board nor the PCM2702 board produced by 00940.

To be honnest with you, there's only one reason for that : it wasn't grounded in the Eagle's library ;)

I'm also interested in what is the proper grounding for the USB connector shield at the receiving end

It's not really necessary from an electrical point of view, but it is much better mechanically as there is quite a lot of force involved in removing/inserting the USB plug. I've got modified Eagle libraries with this done. Please EMAIL if you'd like a copy.