Range of voltage drop across schottky diodes...

[alank2]

I noticed when looking at Digikey's list of them that there are ones that drop as much as non schottky diodes.

What are they designed for?  The minimum drop for X amount of current?

What I am looking for is the minimal amount of voltage drop - I'm using them to support two power inputs and don't want either to back feed the other.  Should I look for the lowest voltage drop and at the same time for it to handle the current I need?  In this case <500mA at 5V DC.

[michaeliv]

It's generally a balance of voltage drop + recovery time + reverse current + price.
So even if they have a higher voltage drop than a regular diode they will have a much lower recovery time.
Is this what you are asking .. "why do they exist?"

For your scenario you probably don't care about 1ma reverse current and a few hundrend uS of recovery time, so yes, look for lowest voltage drop.

[Seekonk]

A low reverse voltage generally goes with low forward voltage.  There is a big penalty going above 40V.