Initial Conditions (ic)
Description
The ic statement is used to provide initial conditions for nodes in transient analysis. It can occur multiple times in the input, and the information provided in all the occurrences is collected. Initial conditions are accepted only for inductor currents and node voltages where the nodes have a path of capacitors to ground. For more information, read the description of transient analysis.
cmin for a transient analysis, does not satisfy the condition that a node has a capacitive path to ground.Definition
ic <X[:param]=value> ...
This statement takes a list of signals with the state information to the DC and transient analyses. X can be a node, a component, or a subcircuit and param can either be a component output parameter or a terminal index. To specify a class of signals, use the pattern matching characters * for any string and ? for any character.
The concept of nodes for the statement has been generalized to signals where a signal is a value associated with a topological node of the circuit or some other unknown that is solved by the simulator, such as the current through an inductor or the voltage of the internal node in a diode. Topological nodes can either be at the top-level or in a subcircuit.
ic 7=0 out=1 OpAmp1.comp=5 L1:1=1.0u
where, 7=0 implies that node 7 should start at 0V, node out should start at 1V, node comp in subcircuit OpAmp1 should start at 5V, and the current through the first terminal of L1 should start at 1uA.
For more information, refer to The ic and nodeset Statements in the Spectre Classic Simulator, Spectre APS, Spectre X, and Spectre XPS User Guide.
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