S/PDIF out: why use a transformer?

[Thoru]

Hi,

I've a chip that outputs s/pdif data. I only need to convert it to the correct voltage and output impedance. Looking at how others do that I see two options: Some with only resistors and others with a transformer for changing the voltage and some resistors for the correct output impendance.
Why do they use the transformers? For CM-current reduction? I learned that it's better not to use transformers for that purpose...

Thanks in advance,

Remco Poelstra

 

[MWP]

Transformers are probably used to give ground isolation.

 

[Thoru]

Thanks for your reply.

If they use it for ground isolation, then I suppose that I shouldn't connect the ground/shield of the wire to the case of the application, right?

Remco Poelstra