Here's an easy approach. Go to
http://www.national.com/store/view_i...LM2675-5.0EVAL

order the National Semiconductor LM2675 demo board ($8!). All you have to
do is wire input voltage and output voltage (5v, 1A) to the board. It is @
90% efficient.

I have been using this converter for my Ipaq this season and it works great.
No RFI that I can tell.

Good luck.
"bcjames" wrote in message
...
I want to build a 5 Volt power suppply to run my PDA in my
glider from the 12 volt battery. Sometimes I use a 14 volt
battery too, so it needs some input voltage range. I'm
looking for suggestions and a DigiKey part number for a
suitable 1 amp DC/DC integrated power supply chip.

I'd like:
at least 80% efficient
no radio noise
Vin of 10.5 to 16.5 volts
Vout 5 volts
1 amp
low cost

I've looked at the LM2825 and the LTC1174-5, but I'd like to
hear from anyone who's done this.

Thanks