Want to confirm a isolation transformer for selected controller ethernet PHY

Often - when encountering such challenge - your "modeling" your design upon the (earlier) successful efforts of others - makes great sense.

In your case - have you reviewed this vendor's, "Eval boards and/or Launchpads" - which provide your desired functionality?    Usually such boards will contain a "BOM" (Bill of Materials) which will list the components selected.     You may then note the "devices of interest" - then acquire the data-sheets of those devices - noting the key features/functions/specifications.    

Would it not prove useful to "employ the exact device" used by this vendor?    (most always - vendors give "good thought" to the devices chosen for their "Sales Aids."    Especially for their Sales Aids.)

Suitability may depend upon "your" desired performance level, voltage/current requirements, physical size, ease of assembly, and price/availability.     It is unusual for "new users" to have such information, "at the ready."    Following the "lead" of the vendor's choice makes (again) "great sense" in that instance...

Thank you so much...