LMK04821: What is the difference between LVPECL16, LVPECL20 and LCPECL?

Part Number:LMK04821

Hello Clock Support Team,

There are three options for LVPECL output. What is the difference between LVPECL16, LVPECL20 and LCPECL? Which LVPECL option should I select when connecting with OSCinP/N of LMX2592? 

Best regards,

Alice