I'm going to use an LM2596.
My maximum input will be 40V to a fixed output 5V 3A.
I've read in the datasheet that for Cin you need 1.5x for an electrolytic capacitor. So 40V x 1.5 will be some 60V. I've seen design and images from google of DC-DC Buck Converters featuring LM2596. They seem not to use 60+ V for Cin but can handle upto 40V input. What is going on here?
I've seen some schematic of that also only using 50V. Link.