--===============0128966042== Content-Type: text/plain; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by pch.mit.edu id kAK1cVeA025855 Spehro, >The requirement for high voltage operation *and* R-R operation is quite >rare, in fact I suggest it might be an error to add that constraint.=20 >Usually Yeah, don't I know it! Unfortunately it's just one application. This particular part is being= =20 used for doing some analog math on control voltages to some CCA gain bloc= ks.=20 The greater the rail voltages, the greater the headroom in the system. = =20 The gain blocks are set up to be "off" when the CV is at the negative rai= l,=20 hence the negative rail requirement. The positive rail would be nice, to= o,=20 but getting close to the negative rail is a lot more important or else=20 there'll be bleed-through. I've used the 324 lots of times and like it fine, but it has this goofy= =20 output stage (well, not really goofy -- it's designed for low-power=20 consumption, which I don't care about) that has a noticable glitch at the= =20 crossover point into high-ish impedance loads. It's really visible on a=20 scope and audible if the signal in question is audio. But the 324 does g= o=20 down to 20mV or so of the negative rail, and it's cheap, and has a wide=20 range of operating voltages. As for the other specs, any parameter I=20 didin't list isn't something I'm overly concerned with. If I can't find a part that works, I'll just use the 324 or bring down = the=20 rails and recalculate the biasing. But I'd like to not have to. Even a= =20 R-R (or just the negative rail) part that was okay with +/- 10 would be=20 pretty great. Thanks again, everybody! TB >From: Spehro Pefhany >Reply-To: "Microcontroller discussion list - Public." >To: "Microcontroller discussion list - Public." >Subject: Re: [EE] Op-Amp Recommendations >Date: Sun, 19 Nov 2006 16:00:53 -0500 > >At 03:08 PM 11/19/2006, you wrote: > >Todd Bailey wrote: > > > > > Hi there-- > > > > > > A little brain picking question- > > > Do any of you all have a favorite op amp that: > > > > > > a.) Has a rail-to-rail output or at least swings to within 50mV of = the > > > negative rail, b.) Runs on +/- 15v supplies, c.) Is cheap (less tha= n > > > $2 for <1000 pcs, preferrably less than $1), d.) Preferrably has mo= re > > > than one amplifier per package, e.) And is not the LM324? > > > >I guess you didn't mean LM324 as it's not rail to rail. How about > >the LMV324? I have > >a feeling it may be among the cheapest. Data sheet says ouptut swing > >is V+-10mV > >and V-+65mV with 10k load, so perhaps it may meet your spec at a highe= r=20 >load > >resistance? > >It's only good for 5.5V absolute maximum supply voltage, which might be >a problem on 30V (+/- 15V). > >The requirement for high voltage operation *and* R-R operation is quite >rare, in fact I suggest it might be an error to add that constraint.=20 >Usually >when you have +/-15V supplies your signals are limited to 10 or 12V. > >If it's two separate applications, then two separate part numbers are >probably called for, rather than trying to find one magic op-amp that >can do it all. > >Best regards, > >Spehro Pefhany --"it's the network..." "The Journey is the=20 >reward" >speff@interlog.com Info for manufacturers:=20 >http://www.trexon.com >Embedded software/hardware/analog Info for designers: =20 >http://www.speff.com >->>Test equipment, parts OLED displys=20 >http://search.ebay.com/_W0QQsassZspeff > > >-- >http://www.piclist.com PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist _________________________________________________________________ Get the latest Windows Live Messenger 8.1 Beta version.=A0Join now.=20 http://ideas.live.com --===============0128966042== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: 7bit -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --===============0128966042==--