>> - Read the spec sheet and do whatever it says you need to do.

> In defense of the original poster, I checked the Fairchild datasheet
> for this part, and it was remarkably devoid of the usual advice that
> I see for regulators about input and output bypassing, reverse 
> current
> protection, or ... ANYTHING.

I agree - I've already apologised but I'll do it again for good 
measure :-). I thought he meant he hadn't dug into the data sheet well 
enough. I was wrong. The data sheet is in fact totally lacking in any 
information re input & output bypassing, as you say. If this is a 
design that can oscillate without the correct output capacitance, as 
seems to be the case, then the failure to detail this in the datasheet 
is totally unacceptable. Older regulators often needed no output 
capacitor for stability, and adding one often made performance worse, 
but modern LDOs often need one with a given ESR range to maintain 
phase margin. Leave it out and the system malfunctions.


        RM



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