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1.2 Getting Started 15
this topic is discussed in Chapter 2.3). In the following, we choose a complexity-reduced BJT model
from the Analog Insydes model library by setting the option ModelLibrary −> "BasicModels‘".
Note that a quote mark ("‘") is following the word BasicModels.
In[5]:= mnaAC741 = CircuitEquations[op741,
ElementValues −> Symbolic,
ModelLibrary −> "BasicModels‘"]
Out[5]= DAEAC, 33 33
The additional option ElementValues −> Symbolic tells Analog Insydes to set up equations using
the symbolic element values instead of the numerical ones. By default, CircuitEquations sets up
small-signal equations in matrix formulation, but DC or transient equations can be set up, too. See
Section 3.5.1 and Chapter 2.4 for details. CircuitEquations returns a DAEObject which contains
the equation system as well as additional data which is used and extracted automatically by other
Analog Insydes commands. As for Circuit objects, a DAEObject is printed in short notation only
and can be displayed using DisplayForm (we once more omit evaluating the command since the
equation system is too big to be printed here):
DisplayForm[mnaAC741]
Again, you can use Statistics (Section 3.6.17) to get an impression of the equation size.
In[6]:= Statistics[mnaAC741]
Number of equations : 33
Number of variables : 33
Number of entries : 1089
Number of non−zero entries : 171
Complexity estimate : 1.6e21
Importing Simulation Data
When using netlists from external simulators we always have to verify that the models used during
equation setup are compatible to the ones used by the simulator. This is done by comparing
the numerical solution calculated by the external simulator with the solution calculated by Analog
Insydes. If both solutions do not coincide within a tolerable error range, we have to go back one step
and choose different models during equation setup before going on with the symbolic analysis. To
simplify this procedure, Analog Insydes provides the command ReadSimulationData (Section 3.10.3)
for importing numerical data generated by an external simulator. As for ReadNetlist we have to
specify from which format we are reading by means of the Simulator option. The list of supported
formats is shown in Section 3.10.1.
In[7]:= op741data = ReadSimulationData[
"AnalogInsydes/DemoFiles/OP−741.csd",
Simulator −> "PSpice"]
Out[7]=
V26 InterpolatingFunction0.1, 1. 10 6 ,