>
>Here are some part numbers for a variety of charge pumps.  All can be
>configured to generate 5 volts from some nominally lower voltage at or above
>2 volts.
>
>MAX683, MAX682, LTC1317, LTC1316, LTC1308A/B, LTC1305, LTC1304, LTC1303,
>LTC1613, LTC1302, LTC1300, LTC1107, LTC1317/B,TPS60140
>

Probably a little cheaper would be to use a 766x or MAX660 in
a voltage doubler configuration - depending upon the current
required - these would go 20-100 mA.