To estimate minimum input capacitance required for a buck converter to help with power stability & noise suppression, I came across below equation by TI.
The input capacitance value depends on duty ratio, switching frequency, output current & maximum input pk-pk ripple voltage.
Can someone please help to understand what drives the spec for allowed maximum input pk-pk ripple voltage? For e.g., if it's specified as 2% of nominal input voltage value then what are the reasons for setting it to 2%, why not 20%?