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.