Hints, Tips and Solutions&October 2004

Noise Simulations

Introduction:

A customer had 3 elements with identical current and voltage applied.

A. W/L = 10um/2um M=4

B. W/L = 40um/2um M=1

C. W/L = 10um/2um 4 devices in parallel

  1. If the MOS model file has the parameters: noia, noib, noic, Af, Kf and nlev=0 will SmartSpice ignore the BSIM III noise parameters (noia, noib and noic) and simply use AK and KF?There are various ways to calculate the noise. If the model card includes the key word “nlev” then parameters Af & Kf are used. If this key word does not appear in the model card then the parameters noia, noib and noic are used for noise level calculations.
  2. If SmartSpice does ignore noia, noib, noic when nlev is set to nlev=0, then, why do these three cases I have in the netlist not have the same identical noise?