>I'm using an oldy but goody in one of my current projects: National
>Semiconductor LM2623.  Starts at 1.1V, runs from 0.8V through 14V,
>internal switch is good for better than 2A, tiny 4.7uH inductor.  I'm
>powering it with 2x 1650 mAH NiMh prismatic cells (in series) with
>excellent results.

Linear Technology also have a range of switcher chips designed for low 
voltage input. Many are designed for use in cell phones and similar consumer 
equipment, so come in horribly small packages, but there are also a number 
that come in more manageable packages like SOT-23 and SO-8. They also are 
happy to supply a couple of chips as samples for free, if you go through 
their web page.

Another trick with Linear Technology is their Spice program which is 
designed as a sales tool for their chips, so it has much of the range as 
standard items that you can select. The program is totally free and you just 
need to follow the download links from the home page.

For the required inductor, there are several companies can supply these. 
Coilcraft is one I have used, and they also have a sampling program, but 
there are others listed in the LT datasheets. It also pays to use the 
capacitors recommended in the datasheet, as well as a PCB layout that is 
very close to examples they give.

http://www.linear.com/index.jsp
http://www.coilcraft.com/

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