Quick Start Guide PDN Simulation

First Start

When you first start the program, you get a message to set the correct LTspice Path.

The path to the LTspice executeable must be entered here.

Create New Project

Open a new project.

It is only possible to use 2 Layers for PDN simulation. (More Layers may be possible in future versions)

Set the thickness of the dielectric layer to 100µm to get satisfying results.

Draw Planes

Select the rectangle icon on the left and the Layer 2 icon on the right. Now flood the whole board on Layer 2.

Select Layer 1 on the right toolbar and draw a L shape for example.

Place Ports

You have to set the positions of Ports. At this points the input impedance will be calculated. To place a Port select the Port icon on the left. In the Dialog you can click OK. The ID will automatically increment.

Select a position in the middle and at the edge.

Place Caps

Next select the Capacitor Icon on the left.


Select the capacitor with 68µF from the list.


Further you can edit the list or choose individual values.


At program start the list "CapStd.csv" will be loaded. You can edit this file also with other programs.

You can simulate a DC supply with an unrealistic high capacitance value.

Click on a point at the lower right edge to place the "Bulk" Capacitor.

Calculate input Impedance

For simulating the impedance there are several steps necessary:

  • First you have to create a mesh
  • Then click on the Zin icon to start the simulation in background

Show Results

When the simulation has finished the diagram shows the impedance curves of the ports.

By clicking the Zin Icon on the right toolbar you choose to show the impedance distribution. To select the appropriate frequency click on the diagram. The impedance distribution will be calculated for this frequency.

In the AC Settings tab you can choose Start and Stop Frequency and Number of Points.

The copper and dielectric losses are assumed constant for a fraction of the whole frequency range. How many such frequency subranges exists can be set with the Field "Steps"

You can choose Logarithmic Axis for simulation and diagram.

Auto Generate Capacitors

In the Simulate menu you can find the entry "Optimize Capacitor at Port X"

By clicking this item a Dialog appears.

You can select how many capacitors should be added at maximum, the maximum impedance and the maximum frequency where the impedance should be lower than the target impedance.

For calculation the impedance at PortX is used. After finishing the capacitors are added at the position of PortX.


Set "Show Console" in the Settings to see which capacitors were added.


You have to run a Zin simulation to include these caps also in the other Port impedance plots.

You can select overlapping parts by pressing the "N" button on the keyboard. This only works if you do not move the mouse between button presses and if the Edit Window has the focus. Just click on the Title bar of the edit window to set the focus.