eldo_user

DC and Operating Point Analyses
The DC related analyses are:
• “DC Analysis” on page 205
• “Operating Point Analysis” on page 208
DC Analysis
Setting Up An Analysis
DC and Operating Point Analyses
The .DC command performs a DC analysis to determine the quiescent state or DC operating
point (OP) of the circuit. The operating point of the circuit is computed with capacitances
opened and inductances short-circuited. A DC analysis may be requested to determine the stable
initial condition of an analog circuit prior to a transient or AC analysis.
Tip
See “.DC” in the Eldo Reference Manual.
There are seven different types of DC analysis available as shown below:
• .DC with no further parameters results in a single analysis of the circuit’s quiescent
state.
• .DC followed by a component name, CNAM, results in a variation of the element size or
value. The variation sweeps from the value START to the value STOP with the
incremental step INCR. The quiescent state is calculated for each incremental step.
• .DC followed by a voltage or current source, SNAM, results in a voltage or current
sweep of the specified source from START to STOP in increments INCR. The quiescent
state is calculated for each incremental step. A second source SNAM2 may optionally
be specified with associated sweep parameters. In this case, the first source is swept over
its range for each value of the second source.
• .DC followed by the TEMP keyword results in a variation of temperature. The
temperature sweeps from the value of START to the value of STOP with the
incremental step INCR. The quiescent state is calculated for each incremental step.
• .DC followed by the PARAM keyword results in a variation of the value of a globally
declared parameter PARAM_NAME. The variation sweeps from the value of START to
the value of STOP with the incremental step INCR. The quiescent state is calculated for
each incremental step.
• .DC followed by the parameter, DATA=dataname, results in a sweep of the values predefined
in the .DATA command. The quiescent state is calculated for each incremental
step.
Eldo® User's Manual, 15.3 205