Hello, I am simulating a broadband circuit, a transimpedance amplifier that runs to about 30 GHz. SO I am using integrated noise under noise and selecting all the components from 1KHz to whatever frequency I want to integrate the noise too. I then want to rank the top three contributors. I am attempting to run a noise summary in Cadence, by doing a noise simulation in AC. I find that when I run a logarthmic simulation under the noise simulation, ie. I select logarthmic and pick 200 steps per decade, or 200 steps as the number of steps, I get a difference result under the noise summary, with different noise contributors (ie. different top 3 noise contributors) versus when I select a linear noise analysis and pick say 100MHz step size or 200 steps for the number of steps. This is with the same frequency ranges - ie. 1KHz to 30GHz. Why is this ? And what is the difference between a logarithmic and linear noise simulation and when would you use each in Cadence ? For example, in some cases, mostly with less steps and less frequency resolutions in step size, I see the 1/f noise dominating. With larger steps and less frequency resolutions in step size, I see the drain currents dominating - which is what I expect from this circuit. Thanks.![]()
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