Sorry about the previous email sent without new content. I had a stray
button click event :)

On Fri, 19 Feb 2010 00:51:10 +0100, "Dario Greggio" said:
>
> thank you Bob. I did not consider exactly the meaning of "DCR" :) , now 
> I get it. But, still, in one datasheet I can read that DCR (1-3) =0.7 
> OHM and (6-8)=0.5 OHM,
> while in the other (the one you posted), we can see 0.7 Pin 1-3/6-8 & 
> 1.1 Pin 11-9
> 
> So... well, I agree in that the inductance is what matters and it should 
> be the same... but, where can I read it in the datasheet??

Hi Dario,

Each manufacturer can decide how they assemble them. It may be that one
of them makes a mirror image for convenience, so one transformer is
rotated and has the lower resistance winding on the primary whereas the
other transformer has the higher resistance winding as the primary, so
the DC resistance will follow their choices. In that one datasheet you
linked to, the primary inductance is listed as 350 uH, I assume for both
TX and RX. The secondary inductance is not listed, I imagine because any
value they got wouldn't be significant since the common-mode coils are
in the package. I'd say the TX and RX designations are arbitrary and you
could safely swap them.

Cheers,

Bob

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