(ADuM3190)About REFOUT maximum capacitance

Hi !

I have some questions about ADuM3190 REFOUT capacitance.

The datasheet said the maximum capacitance is 15pF.

Q1)

Why can not we use larger than 15pF?

Q2)

What will happen if we use larger capacitance?

Example larger than 20pF.

Best regards

Kawa