The question is general on PHY magnetic layout:
Ideally the magnetics of the Ethernet is embedded in the RJ45.
However in my design, the magnetics must be on board. Furthermore the signals on the secondary of the transformer, that includes common mode choke pass through connectors and motherboard. Total of ~10 Iches.
My question is what is the recommended way to rout the traces reference plain up until they reach to the product Ethernet connector(which is not RJ45):
1) Marinating 100 ohm using chassis ground as reference
2) Passing the traces without reference ground and actually clearing any plane under the traces. (that would be difficult to do along all the race path)
3) Using digital ground as the reference plane of the secondary traces. (In which I believe is wrong to do)
Thanks
Avner
