Transient and small-signal analysis are related simulation modes. In respect to the usability of the simulator, their setup and configuration is very similar. In MINIMOS-NT, this setup is done in the Solve section of the input-deck. The complete specification of the time or frequency domain is done by stepping functions, see Appendix B.
If either the transient or small-signal mode is activated, the simulator switches to the respective mode after the calculation of the steady-state operating point. It is important to note that the transient and frequency stepping functions can fully interoperate with other stepped parameters, such as contact voltages. In order to ensure efficiency, the time and frequency steppings always have the highest priority within one slot. In case one of them should be used as a lower-prioritized parameter, the simulation results must be reordered in a post-processing step (see Appendix C.1).
While the transient simulation mode is enabled via the transient keyword, the small-signal simulation is activated by the keyword ac. The time and frequency domains are defined by stepping functions assigned to keywords time and frequency, respectively. If both modes are simultaneously activated, an error message is issued. The example shows the activation of the transient mode, whereas the small-signal mode is deactivated.
Solve
{
transient = yes;
time = step(0 s, 1e-6 s, 1e-8 s); // start, end, delta
ac = no;
frequency = step(1 MHz, 100 GHz, 10, log=yes);
}
Whereas for the transient simulations at least two steps are always required, a single frequency small-signal simulation is a useful feature. Since the definition by a stepping function is mandatory, a new function stepSingle was introduced. A single stepping might look weird at the first glance, but the extended features, such as slots, justify this concept (see Appendix B).