> As for the MOSFET: my understanding was that the "on" resistance is still
> in the tens or even hundreds of ohms, maybe (hopefully) I'm wrong. But if
> that's the case, why do all the analog switch ICs I've been looking have
> significant on resistance, don't they use FETs to do the switching?
>
> Dave Johnson


They use Itty-Bitty Fets, and so they have large on resistance.
I'm using Pmosfets for a buck reg in my battery charger, that have .02
ohms on resistance. National NDS9400A in an SO-8 package.  This is
handling 2A and not warm enough to notice.