Article View: sci.electronics.design
Article #2067Re: Choosing voltage opamp
From: David L. Jones
Date: Sun, 24 Sep 2006 21:29
Date: Sun, 24 Sep 2006 21:29
39 lines
3347 bytes
3347 bytes
Dana wrote: > "Rene Tschaggelar" <none@none.net> wrote in message > news:4516b746$0$13443$5402220f@news.sunrise.ch... > > Dana wrote: > > > > > "David L. Jones" <altzone@gmail.com> wrote in message > > > news:1159083015.452886.300660@b28g2000cwb.googlegroups.com... > > > > >>Not with +/-5V rails he won't. > > > > > > > > > So help me out here. If he has 5 and -5 rails, , and an input sinewave > comes > > > in, so lonag as the op amp is properly biased, will not the output swing > > > between 5 and -5 (not exactly 5 do to loss), in essence giving a 10vpp > > > signal depending on how the output is referenced to ground. > > > > Only rail-to-rail-output opamps come close to the rail > > at the expense of some other parameter. Meaning RR-Output > > is not exactly free. > > > > Rene > > True. But I think Dave was saying that with a +/- 5v supply, the output > would only be able to get a 5v p-p signal. I would think it would get close > to both the 5 and -5 supply giving close to a 10v p-p output. > Like the original poster mentioned when he observed an approx 8v p-p output. > And back to the original poster, yes if he required an absolute minimum of > 10v p-p out, yes his rail supplies would have to be in line with that > requirement. I was not saying a +/-5V rail will give you 5Vp-p, go have another read. A regular op-amp will only give about 8Vp-p as the OP found out. Only (output) rail-to-rail opamps will get close to the rail voltage. Normal rule of thumb for ordinary op-amps is you design for a 2V margin on the rails, unless you inspect the datasheet and can take it further. Dave :)
Technical Details
Message-ID:
<1159133399.462297.180580@h48g2000cwc.googlegroups.com>Path:
arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!h48g2000cwc.googlegroups.com!not-for-mailReferences:
<1159031128.442881.267560@m7g2000cwm.googlegroups.com> <1159049884.197003.19360@m7g2000cwm.googlegroups.com> <1159055088.803133.110670@m7g2000cwm.googlegroups.com> <12hbo03gj60g349@corp.supernews.com> <1159083015.452886.300660@b28g2000cwb.googlegroups.com> <12hdb1u9m7r9b55@corp.supernews.com> <4516b746$0$13443$5402220f@news.sunrise.ch> <12hdgoef6jcvh33@corp.supernews.com>Show Full Headers
Complete Article Headers
X-Google-Thread: 112d1e,c037ff6b3e0ae32c X-Google-Thread: 111d0a,c037ff6b3e0ae32c X-Google-Thread: 103407,c037ff6b3e0ae32c X-Google-Attributes: gid112d1e,gid111d0a,gid103407,public X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!h48g2000cwc.googlegroups.com!not-for-mail From: "David L. Jones" <altzone@gmail.com> Newsgroups: sci.electronics.design,sci.electronics.basics,aus.electronics Subject: Re: Choosing voltage opamp Date: 24 Sep 2006 14:29:59 -0700 Organization: http://groups.google.com Lines: 40 Message-ID: <1159133399.462297.180580@h48g2000cwc.googlegroups.com> References: <1159031128.442881.267560@m7g2000cwm.googlegroups.com> <1159049884.197003.19360@m7g2000cwm.googlegroups.com> <1159055088.803133.110670@m7g2000cwm.googlegroups.com> <12hbo03gj60g349@corp.supernews.com> <1159083015.452886.300660@b28g2000cwb.googlegroups.com> <12hdb1u9m7r9b55@corp.supernews.com> <4516b746$0$13443$5402220f@news.sunrise.ch> <12hdgoef6jcvh33@corp.supernews.com> NNTP-Posting-Host: 138.130.13.170 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1159133404 20337 127.0.0.1 (24 Sep 2006 21:30:04 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sun, 24 Sep 2006 21:30:04 +0000 (UTC) In-Reply-To: <12hdgoef6jcvh33@corp.supernews.com> User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.7) Gecko/20060909 Firefox/1.5.0.7,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: h48g2000cwc.googlegroups.com; posting-host=138.130.13.170; posting-account=uuUYvgwAAADSJ3KQCTlHipSxNh8rODsn