Lpc2000

>Does anyone know of a simple chip that does two channels
>of buck mode switching step down?

I'm no expert on SMPS design, but wouldn't this normally be done with a 
multitap transformer, rather than two entirely separate SMPSs?

>Is anyone using anything but linear regulation?

I'm not designing anything around an LPC right now, but if I was, I'd be 
using a boilerplate circuit based around the MC34063, because it's 
childishly simple to use, and dirt cheap. If space was a consideration, I'd 
look at one of the more modern, higher-frequency parts.

Linear regulation is feasible for these low-power parts, and it's certainly 
the no-brainer solution for a development board, *but* I wouldn't choose it 
for a new design unless there was some special consideration (e.g. noise 
requirements).

A good switcher is not much more expensive, certainly not difficult to 
build, and it's potentially much more efficient. It also gets you much 
better operation off batteries (esp. with a buck-boost, you could run your 
LPC off a couple of AAA cells and get pretty decent life).

-- Lewin A.R.W. Edwards (http://www.zws.com/)
Learn how to develop high-end embedded systems on a tight budget!
http://www.amazon.com/exec/obidos/ASIN/0750676094/zws-20