[time-nuts] Anybody want a Thunderbolt power supply
Charles Steinmetz
csteinmetz at yandex.com
Thu Sep 1 11:34:08 UTC 2016
Mike wrote:
> I use the TAPR HPSDR LPU
I was unfamiliar with the LPU, so I took a look at the docs. It
develops several voltages, all from a +13.8v source. This means that
the -12v supply necessarily is a switching supply (to get the polarity
reversal). It is unfortunate that the power supply that needs to be
quietest for a Tbolt to perform at its best is the one that will be the
noisiest from this design. (That will be true for any supply that uses
nothing but a positive DC input.)
Speaking of noise, none of the datasheets for the four regulators used
in the LPU gives any noise data. It has always been my experience that
if a manufacturer fails to provide a particular specification, it is
because the part performs poorly in that respect -- so I presume the
noise performance of all of the regulators in the LPU are mediocre at
best for their type.
I have never measured an LPU, but all of the data available makes me
think it is not a promising candidate if one wants the best performance
from a Tbolt.
Best regards,
Charles
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