Hi Most OCXO’s will meet all spec’s with 1 to 10 mV RMS on the supply lead. That’s mV not uV.
If the noise is flat in a 100 Hz to 100 KHz bandwidth, most will meet their ADEV specs with a mV RMS on the EFC line. Again mV not uV. The issue is pretty simple: Things like an EFC or supply FM modulate the OCXO. Phase / time (= what you care about) drops off as 1/f. It’s actually pretty hard to find a reference or DAC that is noisy enough to bother a typical OCXO. Bob > On Dec 11, 2014, at 6:26 PM, Neil Schroeder <gign...@gmail.com> wrote: > > So I've done a lot of work in power lately and I can summarize some of this > quickly: > > The lowest noise LDOs today are the TI TPSa4700/01 up to 36v/1a and about 4 > uVRms noise, and the ADP7154/55 up to 5.5v and 600ma with only *0.9* uVRms > above 100hz. > > Both feature great PSRR -and in the case of the ADI part don't even > recommend filter caps at all. > > The TI however does still recommend some capacitance. > > Now most people's next question is how to get their ruby or their > septuple-oven homebrew design powered by one. The quick answer is an error > amplifier based ldo balancer for the most accurate distribution of current. > Also helps with heat. > > Will share a sketch when at my desk next. > > > On Thursday, December 11, 2014, Hal Murray <hmur...@megapathdsl.net> wrote: > >> >> e...@telight.com <javascript:;> said: >>> If the plan is to use a three-terminal regulator after all, I'd suggest >> not >>> using a low-dropout (LDO) type if the raw input supply is noisy - the >> LDOs >>> usually have PNP output transistors (for positive regulators), so may >> tend >>> to have poorer HF input ripple rejection than equivalent ones with NPN >>> passers. >> >> In this context, what is "high"? >> >> Why don't filter caps solve that end of the spectrum? >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com <javascript:;> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > 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. _______________________________________________ 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.