Hi Gerhard ah yes I didn't know that only old OpAmps have the phase reversal problem. At least in the data sheets for some newer types it is sometimes explicitly mentioned - "no phase reversal" - but for others it is not, and so far I never was enough interested in this problem to find out that it only happens for the JFET ones, but good to know! unless it is mentioned explicitly, I usually assume that it can happen because it once caused me some serious troubles and headache in a circuit board which was not designed by me, but which I had to debug. At that time I did not yet know about this property of some amps.
Tobias On Fri., 3 Apr. 2020, 23:42 Gerhard Hoffmann, <g...@hoffmann-hochfrequenz.de> wrote: > > Am 03.04.20 um 23:08 schrieb Bruce Griffiths: > > One can merely add diodes to the opamp feedback network form a feedback > limiter and maintain the opamp outputs within the range for which the opamp > is well behaved whilst maintaining the increase in slew rate for the output. > > Has anybody here ever tried the OPA698 / OPA699 limiting op amps? > > http://www.ti.com/lit/ds/symlink/opa698.pdf > > A lower 1/f corner would be appreciated, and slightly less noise. > > >> On 04 April 2020 at 04:26 Tobias Pluess <tplu...@ieee.org> wrote: > >> > >> > >> Jup, some of them even have phase reversal when they are overloaded, so > it > >> is perhaps not a good idea in general, but I think there are opamps > which > >> are specified for this. > > That phase reversal thing is a misfeature of old JFET-OpAmps when > > overdriven at the input. It created weird behavior of feedback loops. > > Newer ones have that corrected. > > > Cheers, Gerhard > > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.