zener-phobe

[Samuel Groner]

But if the 700 nV is increased due to thermal--and has more at lower registers + feeding power to something with gain--we're back to square one.

The 700 nV is a measured figure at the *output* of the regulator, so no gain afterwards. And any electronics device has more noise at lower frequencies and higher temperatures, your search for otherwise won't change the physics...

Samuel

 

[PhaseLockLoopy]

The 700 nV is a measured figure at the *output* of the regulator, so no gain afterwards. And any electronics device has more noise at lower frequencies and higher temperatures, your search for otherwise won't change the physics...

Samuel

Hi Samuel
What I really meant was not the regulator having gain -- but supplying something with gain - such as the circuit below that I entered into my simulator a few weeks back-- With the power supply common to all stages, one doesnt want any additional noise

 

[PhaseLockLoopy]

That's not called for really.
People were trying to point out that your circuit, where you measured the excess noise, is disfunctional. The noise your measuring wasn't the zener noise. So you kind of put all of us on the wrong foot by claiming excess zener noise from a defunct circuit that wasn't zener noise at all.

jan didden

Hi Janneman

Yeah -- ok I did get a bit sharp ...but I simply cannot stand forum trolls - if you can't open up a sensible debate on a topic without someone showboating or grandstanding or trying to start a ******* contest, what's the point. Certain people didnt read the first post properly or check the title of the thread .

By the way I found this - http://www.odyseus.nildram.co.uk/RFIC_Theory_Files/Noise_Tutorial.pdf and yes there is zener noise -- and yes they do feature in the design of packaged regulators, regulator circuits and stabalised power supplies -- and yes I can measure it.

 

[cbdb]

What I really meant was not the regulator having gain -- but supplying something with gain - such as the circuit below

The gain is for the input signal not the power supply voltages. Actualy, a properly designed circuits output should have less of the supply noise on it than the rails; power supply rejection ratio.

PS: cant really read the cct in post 22, but it looks like a power amp which should have a decent PSRR.