Photon drive and L78L15 question

[Dirt_diggler]

I found 2 of these on mouse so grabbed one of each. Now I'm trying to figure out which I'm supposed to use.
The confusion lies where they state the Minimum input voltage. 1 says 17v and the other says 35v. Both state 35v as maximum.

Which one do I use?

 

[Mcknib]

If you look at the datasheet you'll see the typical voltage drop or dropout voltage listed as 2v

So I'd say the 17v is correct in that you want your output to be regulated at 15v so a minimum 17v input with your typical voltage drop of 2v would be 15v

The 35v is a typo either that or it's got a humongous voltage drop across it!