[time-nuts] Linear voltage regulator hints...
gigneil at gmail.com
Thu Dec 11 18:26:02 EST 2014
So I've done a lot of work in power lately and I can summarize some of this
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
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 <hmurray at megapathdsl.net> wrote:
> > If the plan is to use a three-terminal regulator after all, I'd suggest
> > using a low-dropout (LDO) type if the raw input supply is noisy - the
> > usually have PNP output transistors (for positive regulators), so may
> > 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.
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