LTspice-Simulation Commands Setting

In this article, we will explain in detail how to set the simulation command used for the following six types of analysis.

The simulation commands used for these six types of analysis can be easily set with "Edit Simulation Command".

For the types of analysis, please see the following article.

How to open "Edit Simulation Command"

Simulation command settings can be made on the "Edit Simulation Command" screen.

Click "Simulate"-"Edit Simulation Cmd" from the menu bar of the schematic editor screen to display the "Edit Simulation Command" screen.

Transient

Setting	Explanation
Stop time	Analysis end time
Time to start saving data	Time to start saving data
Maximum Timestep	Maximum value of time interval
Start external DC supply voltages at 0V	Set initial value of external DC power supply to 0 V at simulation start
Stop simulating if steady state is detected	Stop the simulation if steady state is detected and there is no change
Don't reset T=0 when steady state is detected	Not set
Step the load current source	Step change current source
Skip initial operating point solution	Set the initial value of the element to the initial value of simulation execution

AC Analysis

Setting	Explanation
Type of sweep	Select the type of sweep below. Octave: Every 2 times Decade: Every 10 times Linear: Equal interval List: Specified frequency in list
Number of points	Number of points in simulation Octave: Number of points per Octave (Estimate: 20 to 40) Decade: Number of points per Decade (Estimate: 30 to 100) Linear: Total number of points
Start frequency	Analysis start frequency
Stop frequency	Analysis end frequency
1st frequency/ 2nd frequency/ 3rd frequency	First frequency / Second frequency / Third frequency Set when "List" is selected in "Type of sweep"

DC sweep

Setting	Explanation
Name of 1st source to sweep/ Name of 2nd source to sweep/ Name of 3rd source to sweep	Specify voltage source and current source to sweep ※ You can specify up to three by selecting a tab
Type of sweep	Select the type of sweep below. Octave: Every 2 times Decade: Every 10 times Linear: Equal interval List: Specified frequency in list
Start value	Values of voltage source and current source at the start of analysis
Stop value	Values of voltage source and current source at the end of analysis
Increment	Increase value * Set when "Linear" is selected in "Type of sweep"
Number of points per Octave	Number of points per Octave ※ Set when "Octave" is selected in "Type of sweep"
Number of points per Decade	Number of points per decade ※ Set when "Decade" is selected in "Type of sweep"
1st value/ 2nd value/ 3rd value	irst voltage source or current source value / Second voltage source or current source value / Third voltage or current source value * Set when "List" is selected in "Type of sweep"

Noise

Setting	Explanation
Output	Output signal
Input	Input signal
Type of sweep	Select the type of sweep below. Octave: Every 2 times Decade: Every 10 times Linear: Equal interval List: Specified frequency in list
Number of points per octave	Number of points per Octave ※ Set when "Octave" is selected in "Type of sweep"
Number of points per decade	Number of points per decade ※ Set when "Decade" is selected in "Type of sweep"
Number of points	Total number of points * Set when "Linear" is selected in "Type of sweep"
Start Frequency	Analysis start frequency
Stop Frequency	Analysis end frequency
1st frequency/ 2nd frequency/ 3rd frequency	First frequency / Second frequency / Third frequency * Set when "List" is selected in "Type of sweep"

DC Transfer

Setting	Explanation
Output	Output node name
Source	Input node name

DC op pnt