PCM2912A USB shield connection

Mahendrakumar Reddy Ippagunta

Other Parts Discussed in Thread: PCM2912A

In PCM2912A, where to connect the USB shield cable that is coming from the host? It should be connected to the USB device connector shield or leave it open at the PCM2912A end?

-m

over 14 years ago

0 Michael Gambrill over 14 years ago

TI__Mastermind 25575 points

What is a USB shield? This is not a term I am familiar with but maybe I have heard the same thing called something else.

-Mike

0 Mahendrakumar Reddy Ippagunta over 14 years ago in reply to Michael Gambrill

Intellectual 575 points

Mike, Thanks for trying to help. Shield is part of the USB cable that connects to the metallic casing of the USB connector.

0 Don Dapkus over 14 years ago in reply to Mahendrakumar Reddy Ippagunta

TI__Guru**** 189401 points

Hi,

Wow, this seems to be one of the most debated questions...

From my research, it appears that the shield should be connected at the host only (which takes you off the hook). HOWEVER, the connection on the host side is very complicated! Some people advocate direct short to ground, via a resistor, via a capacitor, etc, etc.

I believe that shields should only be connected on one side to prevent ground loops, but I saw some papers that advocated both ends for extremely high frequency stuff.

Anyway, I recommend you leave the shield floating on your side (assuming you're making a peripheral).

-d2

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PCM2912A USB shield connection