hi;
looks like DS80c400 implements EMAC/MII(media independent interface).therefore it must need an external PHY+transreciver.check out the application notes and refrence design at
http://www.maxim-ic.com/quick_view2.cfm?qv_pk=3609
But my sincere advice is get a redymade board.if you
do not get the components mentioned in the documents
finding equivalent takes hell of a time,especially for
coupling magnetics.
Pranav