LM5141-Q1: How to get the EMI filter formula

Part Number: LM5141-Q1

hi all:

       I read datasheet of LM5141-Q1 , it`s good device for us. For the EMC test I want to know how to derive the formula of EMI filter. could you show me some article or information ? 

thank you so much!

following will show the formula from datasheet. page 27.