How to simulate the whitenoise/thermal noise of the resistor

[gaom9]

resistor noise simulation 4ktr

Hi,
I want to use the resistor as a thermal noise source.
But I don't know how to simulate it.
Can anyone help me? and should we add a current or a voltage to the resisor when we simulate?
I try in hspice, but there is no result.
And does the resistor has thermal noise when there is no current through it?


Thank you.
Best regards!

 

[jiangxb]

Re: How to simulate the whitenoise/thermal noise of the resi

do you want to simulate the thermal noise in transient simulation? this is a difficulty thing. in cadence you can use verilog-A model to model white noise in which it uses random number generator(RNG), so you can try to look for RNG in hspice for white noise model.

 

[gaom9]

Thank you, jiangxb.
I want to make the time-domain simulation.
But if we just add the noise model in it but not the noise from the resistor, will it be different from the real circuit rusult?
And I saw a method call " Monte Carlo based time-domain Hspice noise simulation for CSA-CRRC circuit", but it is too hard.


Thank you.
Best regards!

Added after 1 hours 19 minutes:

I make a white_noise in verilog-a as follow, but it can not work.
// VerilogA for random, resistor, veriloga

`include "constants.vams"
`include "disciplines.vams"

module resistor(p, n);
inout p, n;
electrical p, n;
parameter real R = 50k;
analog begin
V(p, n) <+ white_noise(4 * `P_K * $temperature * R, "thermal");
end

endmodule

What is the matter?

Best regards!

 

[Sadegh.j]

Re: How to simulate the whitenoise/thermal noise of the resi

if you are using ADS you can just put a noise source in series with your resistor

 

[gaom9]

Re: How to simulate the whitenoise/thermal noise of the resi

Yes, but ADS is not suit for my design.

Thank you.
Best regards!

Added after 59 minutes:

I use spectres to simulate the thermal noise of the resistor, and make a noise source V²=4KTR serial with the ideal resistor to act as the thermal noise as showed below.

RES is the noise source. And it is verilog-A code is:

// VerilogA for random, rnoise, veriloga

`include "constants.vams"
`include "disciplines.vams"

module rnoise(p, n);

inout p, n;
electrical p, n;
parameter real r = 50k;
analog begin
V(p, n) <+ white_noise(4 * `P_Q * $temperature * r, "thermal");
end

endmodule

But when I use the tran simulation, the noise can not come out, also I add a amp the it the make the bandwidth big, but it could not come out.

What is the matter, please?

Please help me.

Thank you.
Best regards!

 

[gaom9]

Is the white_noise funtion only used in .AC simulation?
So it can not work in .tran simulation?


Thank you!

Best regards!

 

[paul2]

You could close your circuit and see if there is the noise at output. Put this noise source (grounded at one side) in series with your resistor and ground the resistor, and read the output on the resistor.

Best regards

 

[gaom9]

I have found the answer.
In the old version spectre, it do not support the tran noise simulation. We should choose the later version of it.


Best regards.