Simulating tran noise with QSPICE

As a designer who is more acquainted with BSIM3+ simulation models for integrated circuits, I am interested in running transient noise sims. Does QSPICE have this functionality? I haven’t used LTSpice in-depth, so I’m unaware whether this was an option in the original simulator. Does anyone have the answer, or have a simple way to emulate an uncorrelated tran noise sim similar to spectre or hspice? Thanks!

QSPICE will handle stochastic noise of the linearized circuit from first principles, but semiconductor models can be decorated with flicker noise.

Normally, it’s used for looking at the noise of an amplifier, i.e., one specifies an input and output.

But you can have it just report the noise across an open circuit resistor. There’s an example included in the release, Noise.qsch, that shows (i) the stochastic noise of a resistor and (ii) how to make a resistor with noise below the Johnson-Nyquist limit of sqrt(4·k·T·R·BW).



While this does generate a pseudo-random noise source, it does not generate an uncorrelated noise source for multiple sources (random() moves together).

Give each instance of random() a different offset to uncorrelate.