Re: [sdiy] Opamp that gets close to the rails?

[Roman]

Search for any modern opamp with rail-to-rail feature or low power supply headroom, and you're done.
http://www.national.com/parametric/0,,2801,00.html
http://www.analog.com/dynamic/parametric/scResultsDisplay.asp?SearchType=PSS&ProductLine=OPA
http://focus.ti.com/docs/search/vparamsearch.jhtml?searchId=25520&familyId=78&tfsection=param_table&templateId=3&showAssociated=false
and others

Or add one transistor and use your TL082. A n-channel J-FET, like BF245 will do. Drain to +10, source is your output then (add a resistor in, say, 3k range to ground), gate to opamp's output.

Hope that helps

Roman

---- Wiadomość Oryginalna ----
Od: David Cornutt <cornutt at hiwaay.net>
Do: synth diy <synth-diy at dropmix.xs4all.nl>
Data: Tue, 25 Nov 2003 19:13:50 -0600
Temat: [sdiy] Opamp that gets close to the rails?

>I'm trying to build a simple voltage summing circuit, so I can
>jack up the output of my MIDI/CV converter to feed to my EML 101.
>Among the 101's perversities is the fact that the keyboard uses
>an offset control voltage; the left edge of the keyboard is not
>0V but 5V.  The right edge is about 9.8V.
>
>I would like to power this circuit off of the 101's +-10V output
>which is available on the panel, because it's convenient to
>do it that way.  Is there an opamp that can get its outputs
>to within 0.2V of the supply rails?  I vaguely recall seeing a
>thread on this recently, but it doesn't seem to have made it
>to the archive yet.  I'm currently trying to use a TL082 and
>it goes non-linear at 7.1V with +-9V supply in a unity-gain
>circuit with reasonable resistor values.
>
>If there isn't, I can power it using a +-15V supply, but that
>means the box won't fit where I want to put it, so it would be
>nice if I could use the EML's 10V outputs.
>
>