I've built some switchers and I think your best bet it to use the switcher
as a preregulator then a linear at the output of the switcher.  Switchers
have worked very well for me when you are careful to follow the design
instructions and curves etc. on the datasheets.  Just make sure you are
using the right caps, inductors etc. (they even give you part numbers from
different manufacturers on the national datasheets).

On Sat, 15 May 1999, Roland Andrag wrote:

> Firstly, thanks to everyone who responded to my original enquiry - the
> advice is greatly appreciated.
>
> I have given switching power supplies a close look, and they are definitely
> a much less crude solution than linear with huge heatsinks etc. I am just
> worried about the switching noise, which should not be a problem for the PIC
> part of the application or the part that requires the high current, but will
> probably be a problem for a strain gauge amplifier (instrumentation
> amplifier) I am using.  I have some questions to anyone who has experience
> mixing low level analogue circuitry with switchers:
>
> 1. Can I use a separate 78lxx type regulator supplied straight from the main
> 24 V supply to supply the analogue part, and a switcher for the rest, or
> will the switcher induced line noise on the power line still make my life a
> misery?
> 2. If I use only the switcher, will I be able to get the supply clean enough
> using RC low pass filters (bypass caps), or an LC notch filter, or will my
> life become a still become a misery?
> 3. Any other advice/suggestions?
>
> Thanks
> Roland
>