[time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS

[Steve]

> 
> Having designed LDO chips, people expect them to perform miracles
> well beyond reality. If you have a PNP pass and you are sitting near
> dropout, you get control loops that are an ugly combination of a path
> to keep the PNP from getting saturated plus one to control the
> voltage.
> 
> I never really warmed up to
> PNP pass devices, but they are best for high voltage applications.
> 
> 

>I was under the impression that the industry as a whole got away from
>PNP pass back in the 80s. Off the top, I can't think of any PNP pass
>regulation designs worth using.

>You've got my curiosity when you mentioned high voltage. Seems to me
>that PNP is even worse at high voltage, owing to the majority holes as
>carriers rather than majority electrons as in NPN.

>Why are PNP better for high voltage than NPN?  (I've been using PNP for
>nearly everything for about 20 years) .. every now and then i get lazy
>and grab a PNP, but that's beyond the context ;)

No matter how many times i read something, I miss a major typo and
don't see it until right after I hit send! 
Should read:
(I've been using NPN for nearly everything for about 20 years)

Steve