How to calculate the noise in LTSpice of an LT1021 buffer amplifier.

[blackdog]

Hi,

I'm a beginner in LTSpice and I can't figure out how to tie an LT1021-7V reference to my circuit and then look at the total noise.

I'm developing a reference buffer to scale a 7V reference to 10V.
The reference buffer must be idiot proof and have the lowest possible noise contribution.
There are some more requirements I have but that will come later when I show you the whole thing here on the forum.
The schematic below is not complete, the protection is not in the schematic.

First the schematic where now is an LT1021-7 is placed at the input of the buffer and the not working comand for measuring the noise.


The picture below is of the noise behavior of a noiseless 7V voltage source so not the LT1021-7, this is my reference.
The intention is that I want to see the difference with a real reference, so I don't have to make adjustments if the reference circuit used, if the LT1021-7 or other Reference is dominant for the noise behavior of the whole circuit.


So I would like to know if it is possible, of the present voltage references in LTSpice, to show their noise in my schematic and how I do it in the simulation command.
This command that I already modified in several ways does not work: .noise V[Vout] U3 dec 100 1 1000
Do the voltage reference in LTSpice have a noise parameter?

Thanks

Kind regards,
Bram

[blackdog]

Hi 3roomlab,

Thanks for the awnser, do you know if the LTZ1000 has a noise profile?

Kind regards,
Bram

[3roomlab]

Hi 3roomlab,

Thanks for the awnser, do you know if the LTZ1000 has a noise profile?

Kind regards,
Bram

i tried [.noise] for some diode, it has a noise plot. but i have not seen a LTZ1000 noise model.  most of the time i use BV and AC = 10uV for estimation.

* for reference, the AD587 model looks like it has accurate noise parameters
and the chart looks similar to 1021

https://www.analog.com/media/en/simulation-models/spice-models/ad587.cir

** added BV alternative