[time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS
Steve
iteration69 at gmail.com
Mon Feb 27 04:57:36 UTC 2012
>
> 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
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