Difference between circuit node and physical node in PowerDC tool

After performing the setup of VRM in the PowerDC tool, when you try to link the selected nodes, you might observe two options: "Save with circuit node" and "Save with physical node".

Let’s see the differences between them and learn how to use them appropriately.

Circuit Node

There could be many active and passive components on a board. The V-I curves of these components could be different, but they could be connected in the layout nodes to the circuit pins. A circuit node is a node in the SPICE netlist terminals. In the Component Manager, you can click on a component to see the circuit node as “Ckt Node”.

In the above image, the circuit nodes are 1, 1, and 2 for component U-clk1. These nodes are connected to physical nodes, which can be seen under the “Layout Node” heading. To see the link between a Ckt node and a physical node, click on the Ckt node and then select the physical node by clicking on the layout. Then, do a right-click and select Link.

So, a circuit node is a SPICE node. It will have a physical presence on the board, when linked.
 

Physical Node

A physical node is a node that is present on the board. You can place a physical node anywhere on the board by selecting Edit > Node > Add.

In the Set up VRMs section, there are two options to link the selected nodes: Save with circuit node and Save with physical node. The Save with circuit node option links the circuit nodes to the selected physical nodes with the selected terminal. On the other hand, the Save with physical node option directly connects the selected physical nodes with the selected terminal.

Team SimTech

Cadence Design Systems