[time-nuts] Totally unrelated, but..

Gerhard Hoffmann dk4xp at arcor.de
Wed Dec 7 20:12:54 EST 2016

Am 08.12.2016 um 00:50 schrieb jimlux:
> On 12/7/16 3:32 PM, Richard (Rick) Karlquist wrote:
>> On 12/7/2016 12:16 PM, Clint Jay wrote:
>>> I was looking for a low noise regulator to power a log amp/detector
>>> earlier
>>> this year and was rather surprised to find the 78xx regulators were
>>> considerably better than many of the "low noise" devices.
>> Are you kidding me?  Check out the Linear Technology LT3042 and
>> LT3045 with 2 (yes, TWO) NANOVOLTS/root-Hz spot noise.  Orders of
>> magnitude better than the 78XX introduced 45 years ago.
> I'd second the recommendation for the LT3042 - I'm using them in a 
> science instrument which is very noise sensitive.

I can only point again to my own measurements under comparable conditions:


The LT3042 outclasses the old crowd, whether they are called low noise 
or not.

Don't overdo it with the output capacitor, the 4.7uF from the data sheet 
is ideal.

Too much, and the response gets a peak. The pic was taken from a dead 
bug implementation

involving a Micro-SO with thermal pad on the belly, too horrible to show.

There is also a pic with an external D44VH10G power transistor to supply 
more current.

And remember, 0dB == 1nV/rtHz is the INPUT voltage noise of an LT1028 or 

(give or take 10%...)

regards, Gerhard


Ulrich, I seem to remember that you were in Ulm in a previous life.

Then you might recognize the Blau valley on the leftmost image. :-)

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