Flicker in noise analysis

sergio.pesenti · September 29, 2025, 7:17am

Hello,
I am trying to generate flicker in a noise analysis with either a resistor or behavioral source using the KF and AF parameters. But only thermal noise shows up in the plot.

Am I missing a statement to correctly enable the flicker noise?

KSKelvin · September 29, 2025, 5:22pm

Flicker noise is current-dependent!
However, there was a bug in AF; update to the latest Qspice version to fix it.

sergio.pesenti · September 30, 2025, 6:35am

Hey Kelvin,
Thanks for the explanation. My bad. Even in my mother language (VerilogA) the flicker noise is described that way:

where AF is the exponent of the current.
Thanks for your patience.