There is no direct way of doing this that I know of, though you might take a close look at the noise parameters ('spectre -h bsim3v3' if using bsim3). You might find a global thermal noise scaling factor that could be set to 0.

I've seen two basic approaches to getting around this problem, neither are very satisfying. In one, you basically build a duplicate MOS model in Verilog-A but without the noise sources and use it for the noiseless device. The other approach is to continue to allow the device to be noisy, but simply do your own computation of total output noise or whatever you are interested in, but exclude the individual contribution from the device that you would like to be noise free. The individual noise contributor summary gives you enough information to do this.

-August

I believe the parameter you need is gamma (at least for bsim3v3). I think if you set gamma to 0 the thermal noise of the channel goes away. If you also set kf to 0, the flicker noise goes away. You would have to set the value of any parasitic resistors to zero go get rid of their thermal noise.

-August

Doesn't the "print noise summary" list the noise contribution from each device so that you don't have to make individual devices noiseless?