"Joerg" wrote in message
t...
Tantalums?

Nope, electrolytics... the high-quality Panasonic variety.

I don't trust them from here to the door frame. Why do you need such low
ESR?

Well... it's a combination of getting an electrolytic cap that'll handle the
ripple current, and that usually drives you to a pretty low ESR and hence
high-capacitance capacitor anyway as well as supplying current to the load
(which steps between 0 and 1A) while the switcher "catches up." Minimizing
ripple is also always good (this is really the same thing as handling the RMS
current, though, since AFAIK the idea is that self-heating is due to the ESR
and therefore ESR is directly proportional to ripple current handling
capabilities). Having

BTW regular ceramics are really low as well. That's what I always use on
switchers and I can't recall ever having gone above 10uF.

If you keep the ESR the same (15mOhm) and change the output capacitor to 10uF,
in my simulation you end up with a little more than 2V of ripple... ouch! :-)

---Joel