Spice Simulation Use a focused testbench such as <package /testbench/test <scenario .zen for one behavior: startup, enable, a protection threshold, or current limit. Reuse an existing bench when it covers the request. Run it with pcb sim <file .zen ; a separate dummy simulation is only useful when diagnosing setup problems. Model and testbench The leaf component needs spice model=SpiceModel(...) . Obtain a vendor model or, when appropriate, use a behavioral model with explicit limitations. Match nets to the subcircuit's declared terminal order: Instantiate the module under test and needed loads/passives in Zener. Put sources, waveforms, analysis, and plot commands in the raw ngspice setup string of a top level Simulation : Adapt the source and analysis to the behavior; for example, PULSE(...) for enable timing or PWL(...) for a changing input. Write plots under testbench/output/ and inspect only the signals needed to establish the result. Distinguish a model or simulator failure from an electrical finding, and state what the model and analysis actually verify.

spice-sim