Performing a Transient or Convolution Simulation

Start by creating your design, then add current probes and identify the nodes from which you want to collect data.

For a successful analysis:

• When selecting sources, you can use either frequency-domain or time-domain sources. Transient sources are under the Sources-Time Domain palette. They are identified by the small t in their names (for example, VtStep:Voltage Source: Step).
• Add the Trans component to the schematic. Double-click to edit it. Fill in the fields under the Time Setup tab:
  • Enter the start and stop times.
  • Enter the Max time step. This is the largest time step that will be used in the simulation. It should be small enough to adequately sample the highest frequency expected in the circuit.
• To achieve the most accurate model, select the Convolution tab and set the Max Frequency and max impulse sample points. The other parameters here are related to generating impulse responses for convolution analysis, but in general accept the defaults. For more information, refer to the sections Convolution Analysis and Setting Max Frequency and Other Convolution Parameters.
• If frequency is not defined by a frequency source, select the Freq tab and set the fundamentals and order.
• The parameters under the Integration tab set truncation, integration techniques, and charge accuracy. For information on integration techniques, see Integration Methods Used in Transient-Convolution Simulation.
• The parameters under the Convergence tab are used to improve convergence. For more information, see Solving Convergence Problems.
• You can use the steady state detector to find out the steady state conditions of a circuit. See Using the Steady State Detector and Transient Assisted Harmonic Balance.
• It is recommended that parameters not specifically mentioned here be left at the default values. For more information about each parameter, click Help in the Trans dialog box.