SIwave: Unleash the Power of the DC IR Solver
Introduction
This video discusses the use of SIwave for power integrity (PI) and signal integrity (SI) analysis, focusing on the DC IR solver. The DC IR solver is particularly useful when all the dies in your PCB carry a fixed amount of current, such as in TIAs, power amplifiers, and drivers. If any die carries variable current, a DC plus PI analysis is necessary.
Key Features of SIwave
- Calculates voltage drop in power planes and voltage rise in ground planes.
- Analyzes current distribution and detects overloading in vias.
- Identifies potential ESD issues and other defects.
- Extracts information such as stack-up, materials, components, and nets from imported files.
Setting Up SIwave
Before using SIwave, it is recommended to thoroughly read the electrical schematic. SIwave understands the language of nets and identifies single nets as electrically connected structures without external components. These nets can occupy multiple layers but cannot be electrically disconnected.
Assigning Ports
To begin solving, assign ports in SIwave. You can select from:
- Voltage source
- Current source
- Voltage probe
- Termination
Simulation and Analysis
- Configure the simulation by populating the ports and preparing the structure for solving.
- Validate the setup and start solving.
- Examine the results, focusing on:
- Voltage distribution across power planes and ground planes.
- Current distribution to identify bottlenecks and potential ESD issues.
- VIA density to ensure no VIA is overloaded.
Advanced Features
SIwave provides advanced features such as:
- Exporting a power tree to visualize current flow and connections.
- Generating SPICE netlists for further analysis.
- Refinement statistics to ensure smooth convergence.
- Simulation properties to review and compare results.
Conclusion
SIwave offers a comprehensive set of tools for analyzing power integrity and signal integrity in PCBs. By utilizing its features, users can ensure the reliability and performance of their designs.
Note: Ozen Engineering, Inc. is referenced in the context of this transcript.
SI wave: Unleash the power of the DC IR solver SI wave is a power integrity and signal integrity tool that includes a DC IR solver. This video discusses how to use DCI for power integrity analysis.
DCI should be used when all the dies in your PCB or the ones you want to analyze are carrying a fixed amount of current. If one of the dies is carrying variable current, you need to do DC plus PI analysis.
The solver calculates the voltage drop in any power plane, voltage rise in the ground plane, current distribution, current in each via, detects overloading in any via, detects any massive current accumulations, identifies the location of potential ESD issues, and many other defects.
When importing a file into SI wave, it extracts various kinds of information, such as the stack-up, material, components, and nets. The user must assign ports before starting the analysis. It is recommended to read the electrical schematic well before using SI wave.
SI wave understands the language of nets and immediately starts looking for single nets. A single net is an electrically connected structure without the use of any external component. To analyze a power plane, one needs to identify its nets.
If there are many nets, they should be connected using resistors or inductors, which will construct what is called a passive link. When solving a power plane, one cannot solve one power plane with an integrated circuit in between. The solver generates nodes based on the selected solver.
The user can select the DC solver and fill up the form with all the information that the solver was able to extract from the file. It is recommended to select one passive link at a time and assign ports, voltage sources, and current sources.
The user can also select a voltage probe, which practically puts a probe where they want to know the voltage at that location after solving the problem. SI wave allows the user to save the setup and later upload the same structure again after certain modifications.
The user can then load the setup again and it will be populated for them, so they don't have to repeat the whole thing again. When solving the problem, the user can configure the simulation, which populates the ports and prepares the structure for solving.
The user can then validate the simulation and start solving the problem. The user can examine the voltage of the power planes and the voltage rises in the ground. The voltage rises in the ground are as important as the voltage in the main VCC line.
The user can also look at the current distribution inside their power plane. SI wave provides information about the amplitude of the current as well as the direction of the current. Any concentration of currents must be examined by the user.
If it turns out that the section is narrow, one needs to find a way to widen it. Also, watch for any sharp corners. The most important thing from the analysis of the DC is the VIA density. How much current is flowing in the VIAs. The user can see that by going to display element data.
SI wave will populate the dialog box for them, and they can select VIAs. SI wave will display all the VIAs and how much current is running through them. SI wave can identify sections with voltages greater than or less than certain values.
It can also find regions with current density above certain values. These things can be used to examine the board section by section and make sure that there is nothing, no weaknesses within the structure, within the design.
The user can look at the power distribution and see that the power distribution is almost identical to the current distribution. This information is important if the user wants to do a thermal analysis.
From these values of the calculations of the power density and the current and the voltage, the user can also calculate the loop resistance. The loop resistance is practically the total resistance of the main line and the return path.
SI wave allows the user to export things, such as a power tree and a netlist SPICE model. The power tree is a flow chart that summarizes everything in one place in a graphical way. The netlist SPICE model can be used for further analysis.
After solving the problem, the user can check for refinement statistics, such as convergence and the profile. The profile will give information about the mesh used in each section and the time it took to solve the problem.
The user can also look at the simulation properties, which will take them back to their setup. This is important if they are reviewing the results after measuring. It will help them do the right thing.
In conclusion, checking the solution, displaying data in many forms, and exporting data in many forms are the things that the user of SI wave can do. Of course, the DCIR solution is just one of the many features of SI wave.
