New Models Simulate RF Circuits - Intusoft

When simulating in SPICE it is best to use a subcircuit representation
for a device rather than forcing model parameters to have
unreasonable values. If model parameters are used outside their
physical bounds, the model may work well in one area, but
incorrectly in another. For example, the device may behave
properly during the AC small signal analysis, but poorly during the
nonlinear transient analysis. Some vendors who produce SPICE
model use this approach and the user should beware. Models for
RF transistors that are going to be used for both linear and
nonlinear analysis can not be produced this way. A subcircuit
representation must be used!
Note: Parasitics for the passive elements were maintained for
both simulation cases.
1.000
14.69
0
12.69
VOUT in Volts
-1.000
-2.000
VPOWER in Volts
10.69
8.690
1
2
-3.000
6.690
5.000N 15.00N 25.00N 35.00N 45.00N
WFM.2 VPOWER vs. TIME in Secs
With Bead and Parasitics
11.81
1.000
1
9.811
0
VPOWER in Volts
7.811
5.811
VOUT in Volts
-1.000
-2.000
3.811
-3.000
2
5.000N 15.00N 25.00N 35.00N 45.00N
WFM.1 VOUT vs. TIME in Secs
No Beads with Parasitics
Figure 4, Comparison of the start-up and power supply waveforms with (Top) and
without (Bottom) the new RF bead model.
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