[sdiy] Opamp question, I like to hit the rails

[John L Marshall]

How about one, two or three diodes drops to create a floating ground? You
would end up with around +9.9 volts and -2.1 volts.


Take care,
John
www.sound-photo.com
---------------------------------------------------------------------------

----- Original Message -----
From: "harrybissell" <harrybissell at prodigy.net>
To: "Theo" <t.hogers at home.nl>
Cc: "John Blacet" <blacet at blacet.com>; "Synth-Diy"
<synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, April 09, 2003 7:06 PM
Subject: Re: [sdiy] Opamp question, I like to hit the rails


> Most rail to rail opamps have really low current drive at the rails... why
not
> make
> a charge pump negative supply with some chips like the ICL7660 (iirc) or
some
> Maxim power supply chips. You'd only need a milliamp or two to make it
work...
>
> H^) harry
>
> Theo wrote:
>
> > I don't have a negative supply available and need a CV from a LFO
between 0V
> > to 5V.
> > The supply is 12V so there is enough headroom at the top.
> > But to get (close to) 0V going to the rails is the option with least
> > additional components.
> >
> > Therefore I repeat the question: what would be a good (dual) opamp for
the
> > job?
> >
> > Thanks,
> > Theo
> >
> > From: John Blacet <blacet at blacet.com>
> >
> > > The real question is *why* do you need rail to rail?
> > >
> > > --
> > > Regards,
> > > --/////--
> > > John Blacet
> > > Blacet Research
> > > http://www.blacet.com
> > >
> > >
>