eldo_user

Setting Up An Analysis
DC Convergence
Related Topics
DC Analysis
Operating Point Analysis
DC Convergence
DC Convergence
Eldo partitions the circuit in one block or several blocks (especially in the case of large circuits
with MOS). Partitioning iterations are used to find DC convergence. Partitioning iterations can
be disabled by specifying either of the following options:
• .OPTION NODCPART
• .OPTION DCPART=0 (default values is 5)
For DC Analysis, only the Newton Raphson algorithm is used to compute DC.
Tip
See “.OPTION NODCPART” and “.OPTION DCPART” in the Eldo Reference Manual.
Related Topics
Improving DC Convergence
DC Convergence Troubleshooting
Improving DC Convergence
Before any kind of analysis is carried out by Eldo, a DC or operating point for the circuit in
question is usually carried out, unless the UIC parameter is present in the .AC or .TRAN
command.
DC and operating point convergence times can vary greatly, depending on the type of circuit
simulated. Eldo provides some commands that may be used to speed up the convergence
process:
.IC V=value
When used, Eldo fixes the specified node voltages for the duration of the DC analysis. If the
UIC parameter is also present (for example in the .TRAN command), no DC analysis is
performed and the voltages are initialized as defined in the .IC command. All other voltages on
nodes not initialized in the .IC command are determined by Eldo. During subsequent analysis
(transient), the node voltages are freed of their initial values, and may therefore assume different
values.
Eldo® User's Manual, 15.3 211