Groups > sci.electronics.design > #454111

Re: Another op-amp stability question (LT1677)

From	piglet <erichpwagner@hotmail.com>
Newsgroups	sci.electronics.design
Subject	Re: Another op-amp stability question (LT1677)
Date	2017-03-29 13:23 +0100
Organization	A noiseless patient Spider
Message-ID	<obg8qa$se7$1@dont-email.me> (permalink)
References	<28246daf-fd57-48e6-a94e-2e778c9a3973@googlegroups.com> <e2fd268f-5754-48eb-8232-16be73682874@googlegroups.com>

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On 29/03/2017 12:50, pcdhobbs@gmail.com wrote:
>> So... what's up with this?  Can anyone else repro the behavior?  Maybe
>> I just got a bad batch of parts, or I'm doing something dumb.  Hope so.
>
> Where's the supply bypass? First guess is that 100 nF to ground will fix it. Keep the leads less than 1/4 inch long.
>
> Not everything in the amp is as slow as 7 MHz--it looks like the two input stages (required for RRI operation) are fighting each other at the crossover point.
>
> Cheers
>
> Phil Hobbs
>

Datasheet indicates input stage NPN/PNP handover occurs at "approx 1.5V" 
above negative rail so that figures with your observed 1.2 threshold.

piglet

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Thread

Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 00:37 -0700
  Another op-amp stability question (LT1677) pcdhobbs@gmail.com - 2017-03-29 04:50 -0700
    Re: Another op-amp stability question (LT1677) piglet <erichpwagner@hotmail.com> - 2017-03-29 13:23 +0100
    Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 10:58 -0700
      Re: Another op-amp stability question (LT1677) tabbypurr@gmail.com - 2017-03-29 11:15 -0700
      Re: Another op-amp stability question (LT1677) Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-03-29 23:29 +0200
        Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 17:14 -0700
          Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 18:06 -0700
          Re: Another op-amp stability question (LT1677) Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-03-31 14:40 +0200
            Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-31 14:49 -0700
              Re: Another op-amp stability question (LT1677) Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-03-31 20:39 -0400
              Re: Another op-amp stability question (LT1677) tabbypurr@gmail.com - 2017-04-01 09:16 -0700
                Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-04-01 15:03 -0700
                Re: Another op-amp stability question (LT1677) Winfield Hill <hill@rowland.harvard.edu> - 2017-04-01 16:46 -0700
                Re: Another op-amp stability question (LT1677) John Larkin <jjlarkin@highlandtechnology.com> - 2017-04-01 17:31 -0700
                Re: Another op-amp stability question (LT1677) tabbypurr@gmail.com - 2017-04-01 20:59 -0700
                Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-04-01 21:41 -0700
                Re: Another op-amp stability question (LT1677) tabbypurr@gmail.com - 2017-04-02 04:53 -0700
                Re: Another op-amp stability question (LT1677) John S <Sophi.2@invalid.org> - 2017-04-02 16:26 -0500
                Re: Another op-amp stability question (LT1677) krw@notreal.com - 2017-04-02 19:29 -0400
                Re: Another op-amp stability question (LT1677) John S <Sophi.2@invalid.org> - 2017-04-02 18:34 -0500
  Re: Another op-amp stability question (LT1677) John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-29 05:18 -0700
    Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 10:56 -0700
      Re: Another op-amp stability question (LT1677) John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-29 13:02 -0700
        Re: Another op-amp stability question (LT1677) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-03-29 17:57 -0700
          Re: Another op-amp stability question (LT1677) John S <Sophi.2@invalid.org> - 2017-04-02 16:31 -0500
      Re: Another op-amp stability question (LT1677) John Larkin <jjlarkin@highlandtechnology.com> - 2017-04-15 08:58 -0700

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