I am looking to use W5200 in my next ethernet board, however from their datasheet, it seems my current magjack is not the best fit.
( http://www.sparkfun.com/products... )
The datasheet recommends a symmetric one to support auto-midx.
However I am not sure if the resistors are still needed, and how to make sure it has the correct inductance/capacitance.
Except for the resistors, the asymmetric one in the datasheet matches the one from sparkfun (ie. the one the datasheet does not recommend)
Does anyone know of a known working MagJack for W5200(W5100), preferably one that can be had from rs or element14/farnell.
Also: Both Atmega1284 and W5200 has exposed pad to GND, I am thinking about going to 4layers, is it ok to have vias directly in this exposed pad to connect to ground layer?
-And if so, how many vias is good practice ?