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14 1. A Short Introduction
which automatically translates an external netlist description into the Analog Insydes netlist format.
You can import netlists written for or generated by Eldo, PSpice, Saber, and the Spectre to Analog
Insydes interface for Analog Artist.
The first argument to ReadNetlist is the simulator input file. Since this file (*.cir in our case)
only contains the numerical values of the elements, the operating-point information and the values
for the small-signal parameters of the transistors have to be extracted from the simulator output file
(*.out in our case). This is performed automatically by ReadNetlist, too. All we have to do is
specifying the corresponding simulator output file as second argument.
In[3]:= op741 = ReadNetlist[
"AnalogInsydes/DemoFiles/OP−741.cir",
"AnalogInsydes/DemoFiles/OP−741.out",
Simulator −> "PSpice", KeepPrefix −> False]
Out[3]= Circuit
As the syntax of external netlist files varies for each simulator, you have to specify from which
external format you are reading by means of the Simulator option of ReadNetlist.
The return value of ReadNetlist is a Circuit object which contains symbolic values for each netlist
element as well as the corresponding numerical reference information. By default, the Circuit object
is displayed as a single line in your output cell. To view the complete netlist apply the command
DisplayForm to the Circuit object (we will not evaluate the command since the output is too big
to be shown here):
DisplayForm[op741]
Additionally, you can use the command Statistics (Section 3.6.17) to get an impression of the
circuit complexity. This command prints the number of different element types occuring in the
circuit.
In[4]:= Statistics[op741]
Number of Resistors : 13
Number of Capacitors : 1
Number of VoltageSources : 5
Number of models BJT/QNPN741 : 15
Number of models BJT/QPNP741 : 11
Total number of elements : 45
Setting Up Circuit Equations
Once the netlist is imported, the next step is to set up the symbolic circuit equations. In Analog
Insydes this can be done automatically using the command CircuitEquations (Section 3.5.1). The
Analog Insydes netlist read by ReadNetlist contains generic model references for each transistor and
does not specifiy a concrete model implementation. Thus, we have to instruct Analog Insydes which
model to use during equation setup by means of the option ModelLibrary. Analog Insydes comes
with a predefined SPICE-compatible, symbolic model library in three different complexity levels
called "FullModels‘", "SimplifiedModels‘", and "BasicModels‘" (the implemented models are
explained in detail in Chapter 4.3. For special tasks the model library can be extended by the user;