http://focus.ti.com/docs/prod/folders/print/tl497a.html

seems like filling your needs...

   Bruno L. Albrecht
   Eng. da Computa=E7=E3o/06
   Falker Automa=E7=E3o Agr=EDcola Ltda.
   http://www.falker.com.br


On 10/04/2010 12:20 AM, Oli Glaser wrote:
> Hi all,
>
> I am using dual supply opamps in the front end of my prototype USB scope,=
 so
> I need to generate -5V from the USB +5V.
> In the current prototype I am using 2 TPS60401 charge pumps to invert and
> double the voltage to -10V then regulating to -5 with a standard -5V
> regulator (I want to keep it as quiet as possible hence the regulation
> afterwards - this will be replaced with an LDO in the next version also)
> This worked okay for supplying one opamp, but drops voltage when supplyin=
g
> all three of them (it was only a "temporary" measure until I found a bett=
er
> solution)
>
> I guess I could put the TPS60401s in parallel to lower output resistance =
but
> then I would be looking at 4 of them, which seems a bit messy.
> Basically I would like to hear of any decent and cheap ways of doing this
> from anyone who has tackled it before - cheap is important but if there i=
s
> nothing similar in price to the above (~=A30.50) I will pay the extra.
> Any advice would be much much appreciated as I can't seem to find anythin=
g
> really suitable.
>
>
--=20
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