); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Pete wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] > > Magnus, > > This discussion is why I have allowed the ADA4899-1 to saturate in the ZCD > posted earlier. The transition times up & down in the second stage are 350 > to > 400 ns; thus I believe the <50ns overload recovery doesn't degrade the > measured jitter. With 500MHz 'scope bandwidth, the 1KHz squarewave > output has <1% over/under shoot & appears noise free at the zero crossing. > > The output transitions are fast enough for my HP 5370A to show < 1ns > jitter over 1K or 10K samples. > > Regards, > > Pete Rawson > Pete
What about the power supply noise that appears at the amplifier output during saturation? Power supply noise is almost always much larger than the opamp input noise. A simple resistor + diode clamp in addition to the feedback clamp will easily attenuate the output noise of an opamp with diode clamps across its feedback resistor. An npn plus a pnp resistor ccan also be used to clamp the output of an opamp whilst still suppressing the noise gain to a very low value and prevent opamp saturation. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
