Werner,
     
     If you're looking for a switcher, look at the Microlinear ML4890CS-5
     
     It's a combined booster / 5V linear regulator
     Needs a small inductor and 2 or 3 low ESR caps. (OSCON or Tant.)
     Less than 5mv ripple out,
     Works down to 1.0V (I had it down to 0.7V in testing)
     At 2.0V you can get 80+mA out at 78% efficiency, or 18 mA at 90%
     
     I've used it for driving an RFID tag reader that had a max. supply 
     ripple spec of 5mv! Does the job.
     
     data sheet at
     
     http://www.microlinear.com/mltextonly.shtml 
     
        Steve Lawther
     
     (copied to the list in case anybody else is interested)


______________________________ Reply Separator _________________________________
Subject:      2V to 5V conversion
Author:  MIME:wterreb@PLESSEY.CO.ZA at INTERNET-HUSKY
Date:    17/02/98 09:22


I found a nice enclosure that I would like to use for a PIC based 
product.  Unfortunalely this enclosure will only accept two AAA 
sized penlight batteries, whereas many of the IC's in my prototipe 
requires at least 5V.  I'm thinking of using two 1.2V Nicad 
batteries.  Surely many other people on this list have also had a 
requirement for something like this some time or other.
     
I know there are dc to dc converter and voltager doubler IC's 
available from companies like Maxim, but I would still like to hear 
the opinions of other list members about the usage of these types of 
voltage doubler IC's.  Since there will also be a 5V, 12 bit A/D on 
the circuit, I need something that is not very noisy and still quite 
efficient.   I have never had to make such a battery operated 
product before.  What would you recommend or not recommend?  Is it 
feasible to run a 5V based circuit from a 20 - 2.4V  supply with dc 
to dc conversion, or is it not recommended?
     
Rgds
Werner