[time-nuts] Re: Collector current that minimizes BJT noise

[Attila Kinali]

On Mon, 26 Sep 2022 08:53:26 -0700
"Lux, Jim via time-nuts" <time-nuts at lists.febo.com> wrote:

> What has been the list's experience with noise models in SPICE for ICs 
> (e.g. Analog Devices provides SPICE models for low noise op-amps)
> 
> We've been hand calculating using the datasheet values, and then 
> measuring in the circuit, and as expected, we get comparable 
> measurements (perhaps a bit better than data sheet performance).

As far as I can tell, ADI's models are quite accurate for noise.
Though I have not extensively tested them. Neither have I operated
any of the devices at the limits of the specifications. I.e. I have
only ever exercised the models in the region of most common use.

And it seems like since ADI switched to encypted device models, that
they even have gotten more accurate. Might be that they don't fear
to expose device internals anymore.

But my comment on non-linearity and its effects not being modeled
by Spice remain. They are just less important for the low frequencies
where most opamps are operated at. I have not done, neither have I
seen comparison of Spice simulations with measurements of high-speed
opamps operating in the MHz range.


			Attila Kinali


-- 
In science if you know what you are doing you should not be doing it.
In engineering if you do not know what you are doing you should not be doing it.
        -- Richard W. Hamming, The Art of Doing Science and Engineering