dac noise model
I would be concerned about getting the transient noise
amplitude "calibrated", the canonical noise params
which a foundry PDK might model, are not really the
same thing when you try transient noise (I gather
from some very superficial reading).
I think you should get a "standard transistor" (by the
foundry's noise modeling documentation) and try a
static, transient noise simulation and process the
output noise amplitude / spectrum back to a
nV/sqrtHz (or whatever) number, maybe compare
curves if they are shown in PDK docs, to the point
that you believe the fundamental "input" is right.
I think there is a good chance that tnoise params may
not have been set, or set to defaults, and you are hit
with the result.