[SI-LIST] Re: Reg DCR of Isolation Transformer

DCR (DC resistance) is not really the specification to worry about. 
Ethernet coding has a zero at DC, otherwise it couldn't be AC coupled
through a transformer.  DCR can serve as a sort of crude yardstick
regarding what multiple the real part of higher frequency impedance is,
but the essence of the matter is what the spec sheet says about dB of
loss and flatness in the passband.

On the other hand, DCR is directly relevant to implementation of PoE
(power over ethernet).  In that instance it's a straightforward ohm's law
consideration that does not affect signalling (unless you burn the wires
out).

Orin Laney

On Tue, 16 Jun 2009 11:25:45 +0530 Vivek Kumar <vivek8419@xxxxxxxxx>
writes:
> Dear All,
> 
> Please can anyone provide info on how DCR of an isolation 
> transformer
> will affect the ethernet signal.
> 
> What is the minimum value of the DCR required for Ethernet Design?
> What if the DCR is more than the required? what will be its impact.
> What is the Major role DCR play in Ethernet communication?
> 
> 
> Cheers
> Vivek
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