Spectrum Software
Industrial Strength Simulation




Spectrum Software has released Micro-Cap 11, the eleventh generation of our SPICE circuit simulator.

For users of previous Micro-Cap versions, check out the new features available in the latest version. For those of you who are new to Micro-Cap, take our features tour to see what Micro-Cap has to offer.




Easily Overlooked Features - Spring 2005


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.

Cursor tracker with stepping display

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