); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] > John Miles wrote: > >> The output of an opamp is always referenced to its power supply, > >> regardless of the configuration. If the power supply is noisy, > >> the output is noisy. > >> > > > > Beyond a few kHz this may be true, but at lower frequencies > even a low-grade > > opamp has excellent rejection of power supply noise. A good opamp data > > sheet will characterize the PSRR versus frequency. > > > > -- john, KE5FX > > > John > > Only when the opamp is operating within its linear region, not when the > output is saturated. > Opamp saturation has been proposed as a good method of reducing the > output noise of an opamp when an amplifier is overdriven. > This is clearly not true when power supply noise is significant, as is > almost always the case.
Sure; I was mainly objecting to use of the term "always." The statement that "the output of an opamp is always referenced to its power supply" is simply not a good model of the situation near DC, unless (as you note) the output is saturated. -- john, KE5FX _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
