This section is designed to highlight one or two features per issue that may be overlooked because they
are not made visually obvious with a toolbar button.
.TR Command Statement
In a transient analysis, the Maximum Time Step field controls the maximum amount of time that will be
present between two data point calculations. Decreasing the Maximum Time Step will produce more data
points in a simulation but also increase the duration of the simulation run. For some simulations, a
critical part of the transient analysis may require a smaller time step, but setting this smaller time
step over the entire run will create a very long run time. The purpose of the .TR statement is to provide
flexibility in setting the time step for these types of simulations. The format of the .TR statement is
as follows:
.TR [s2 t2...sn tn]
where the s entries are the time step values and the t entries are the corresponding time values that the
time step will be set for. An example .TR statement is:
.TR 30n 150n 1n 400n 30n 2u
In this example, the time step is limited to 30ns from 0 to 150ns. Between 150ns and 400ns, it is limited
to 1ns. Between 400ns and 2us, it is limited to 30ns. A transient analysis is shown below that has
this .TR statement implemented. Note the increased data point sampling between 150ns and 400ns versus
the rest of the simulation.
The .TR statement should be placed in one of the schematic text pages or the schematic itself. It will
have priority over any value set in the Maximum Time Step field.
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