DC IR Drop Analysis Using ANSYS SIwave

Hello, this is Ibrahim Nassar with Ozen Engineering. In this demo, we will be using ANSYS SIwave to perform power integrity analysis based on DC IR simulation. Here's the project open with the SIwave tool. So here's a board file that got imported here.

And you can import basically different types of files by going to File, Import, and these are the different file types that can be imported to SIwave. After you import the file, you can go to the layer stack up, verify the stack up here, and the materials, or modify them.

You can also see the nets that are identified in your model, whether they are single-ended, or if you have extended nets, where our nets basically, if you have a lot of components that are connected with lumped components, you can also define them here by using the auto-identify or manually add them.

You can also define differential nets, and the power ground plane will be automatically loaded here based on the built-in definitions. But if some are not included, you can manually edit those nets to be considered as power ground nets or not.

You can also, from here, check which layer you want to be viewed here, planes, traces, pads, vias, components, so different ways basically to modify the view of the file.

Alright, so now, the DC, the power integrity analysis with SIwave can be done based on different solvers, so if we go to Simulation, there are different types of solvers that we can use, but for power integrity, there is, it can be done using the S-Y-Z solver, or you can use the ACIR solver, which is here, that we will use basically to calculate voltages and currents and be able to plot them in the power plane and view them and identify areas of concern.

Okay, so SIwave basically has different wizards for automating different types of simulations, and we can access that from here for some type of analysis, but for the DCIR analysis, we will access it from here, from the SIwave workflow wizard here.

So if we click here on this icon, this will open, and as you see here, we can start by here, by bringing the files, verify the stack up, and everything. And now, to set up a DCIR drop analysis, we can click here to configure it.

Here, you see the list of all the nets, and the ones in red are basically the power planes, so we can select any of those to do the analysis.

For simplicity, let's just select, for example, this one, and here we see, like, there's two different reference designators here for this part number and this part number, and they. So here, let me go back here to show you where we want to basically set the simulation on.

So we will be using basically this component U1, and this component, if we can't find them, we can hide the planes here to see the components up to this U2, this component.

So we basically put the voltage source here, and a current source here, and calculate the currents and the voltages in these planes. Okay, so we go back here to the SI Wizard. So if we click DCIR analysis, so we select basically which net we want to do the analysis on.

So let's select the one V 0. And here, in the one V0, we want to identify a voltage source. As we mentioned here, it's at this kind of component here. And then we will basically define a current sink to do the analysis.

So where we want to place the voltage source, we basically want to place the voltage source in U2, so we can here click on source probe, change that to voltage source, and on this one, we want to put here a current sink, so current source.

We can obviously here change the magnitude of this, for example, we can use like 1 amp. And that's it.

Now we want to do, click on configure the simulation, so if we click on configure the simulation, the simulation basically setup will be configured, and basically, what will happen is ports will be, and pin groups at these components will be created to do the simulation.

So this is done when we click on this step. Now next, basically, we can validate. If we have any issues based on these criteria, if we have DC short, disjoint nets, for example, you can also modify some of these, and we then click OK, and we do the validation.

So now we see the results, so there are no errors, so we already configured the simulation by applying ping groups and excitations to the design. We did the validation, so now we are ready to simulate.

We here can see also the RLC components that are connected basically on these nets, and we can click here to hide them. So now, basically, all the simulation setup is ready, so we can just click on simulate. Here, in this window, we set up the DC simulation.

So here, you see that we have to select the ideal ground zero volt, and we can modify. Generally, a side wave requires a global zero-volt reference location. The zero-volt reference is automatically applied to the negative pin of the voltage source.

This creates a reference point for the voltage plots and the results. This is fine here. Setup fine. If we click on other solver options, here we can modify the accuracy of the simulation from balance to optimum speed and optimum accuracy. We can modify the circuit element contact radius.

If we go to the DC Advanced tab, also, there are different settings that can control the simulation and can be modified. If we go to the multi-processing tab, we can, as well, modify the number of cores used for this simulation and the type of the HPC license.

Then we click OK, and now the simulation is ready to start, so we can click on launch. OK, so after the simulation is done, we can see the analysis listed here, and the results, and if you perform different types of analysis, they will all be listed here.

So now, let's view the current and voltage, so we can right-click on, let's make fit view here, so by hitting CTRL D to fit all the view.

Now we can right-click on this, and select plot current voltages, so we can select which net we want to make the plot on, so let's select the 1V0, and let's, for example, select to plot the voltage here.

If you don't see that, that means we have some view issue, to do that, we can go to View, and in here, we can click here to display the color scale, and on here, we can select to display the surface plot.

Okay, so now we see the voltage here, and if we select change the different layers, so let's plot it in NR2, as you see here, so we see the voltage plot on that layer.

Similarly, we can select and check this, and select the surface, the current density, and as you see, it also shows up as a vector where it goes. You can also change the scale by double-clicking on the scale and changing it to user-defined values.

We can also view the current Vs, so if we go to plot current voltages.

So if we uncheck this, and select the IV, which is the current via, and let's select it, for example, on inner 2, as well, and by the way, we can also hide all these things, so we just see basically the current at the voltage, so here we see the current via, and shows up also the direction as an X and O, if it's coming in or coming out, and of course, with the scale on.

We can, as well, do different types of reporting. So we can right-click here, and say display element data.

And if we go to the VS, for example, so you see, we can see a list of all the VS, and see the position of it, the current, and if it's passing or failing, depending on the criteria defined, the resistance, and different values.

And you can also do this by pointing on a specific via, so you can see the values here, and read them. And as I mentioned, O and X represent basically the current magnitude between the layers, O as to a layer toward the top, and X current to a layer away from the top of the stack up.

Okay, we can, as well, right-click here, and look at calculate the loop resistance, and here we can expand this window, and see the loop resistance values, and we can, as well, export some data, so if we right-click here again, and select export report, and we can provide, like, location, and we export the report here to any specified location, you can, as well, export the power tree.

Please contact us at https://ozeninc.com/contact for more information.