SIwave: Everything You Need to Know About the MTTF Solver (HD)
SIwave is a power integrity and signal integrity tool. In this video, we will discuss one of its tools, MTTF, which stands for Median Time to Failure. MTTF is essential for understanding the lifetime of a PCB based on the DC current density distribution calculated using the DCIR solver. It uses Black's equation to calculate the median time to failure of a semiconductor circuit.
Definition and Importance
MTTF is defined as a maintenance metric that measures the average amount of time a non-repairable component or structure is expected to last. In a previous video, we demonstrated how to perform a DCIR solution for a PCB. Once you have a solution, you can proceed with MTTF analysis.
Using the MTTF Solver in SIwave
- Click on the MTTF solver in SIwave. A dialog box will appear, prompting you to verify the contents before solving.
- Once verified, the simulation begins. You can monitor the solution's progress.
- After the solution is complete, you can plot the MTTF distribution within the PCB.
Plotting Options
- Plot all layers simultaneously or individually (top or bottom layer).
- Modify the scale settings (linear, log, or dB scaling) for better visualization.
- Display component locations and zoom in on specific areas to assess component lifetimes.
Analyzing Results
To identify critical areas, use the warning and error thresholds set during setup:
- Green regions indicate values below the warning threshold.
- Yellow regions exceed the warning threshold.
- Red regions exceed the error threshold, indicating extremely high current density.
Focus on red spots to address high current density issues.
Additional Features
- Filter regions based on specific operational hours.
- Examine vias, which are the weakest elements in a PCB structure, using a table view to assess their lifetime.
By analyzing the MTTF, you can evaluate the lifetime of the PCB, including metals, components, and vias.
Thank you for watching.
SI Wave is a power integrity and signal integrity tool. MTTF is one of the tools in SI Wave and will be discussed in this video. MTTF stands for medium time to failure.
MTTF is a necessary tool to understand the lifetime of the PCB based on the DC current density distribution calculated using the DCIR solver. It uses Black's equation to calculate the median time to failure of a semiconductor circuit.
In general, MTTF is defined as a maintenance metric that measures the average amount of time a non-repairable component or structure will function without failure. In a previous video, we showed how to do a DCIR solution for a PCB. Once you have a solution, then you can do MTTF.
Like any other solver in SI Wave, when you click on the solver, SI Wave displays a dialog box, prompting the user to verify the contents before it starts solving. If you select MTTF, you can see the solution working. Now, go back to the syllabus, and you can see some details outside the graph.
Perhaps the load is going to be really low, and you can apply an input from your database. Then, you can rotate digital ones by pressing the token to register and the source data, which will respond via a data entry.
This field will restore the load, along with the control data and the map observations in H. Now that you know all the elements, let's move on. Here, in the center, you can see some different parameters you want to use from this engine software.
All of these parameters on this robot tell you what the current product density will be by this type of measurement. In this case, you want to see the continuously, consistent value DSDI for this software.
Adjust, adjust, or modify that, and K is the Boltzmann constant, while T is the temperature of the PCB. That's the temperature you see here. If you have an ice pack, you can solve the temperature distribution and put it back into this formula.
The warning number and the error numbers are just thresholds established at the beginning for post-processing. They will help you zoom in on what you call bad sections very fast. If you are happy with what you see in this dialog box, you can save the setting.
If it's simple like this, you can save it and launch the solution. Once you have a solution, you can plot the results. The first thing you can see is plotting the MTTF distribution inside the PCB.
If you can plot all of them simultaneously, you can plot all the layers or plot the top one alone and hide the structure. Now, you can see the MTTF numbers and the scale. You can double-click on the scale and modify it.
If you move your mouse around, you can see the numbers, giving you a better idea of the time to failure. If you put a component at any one of these locations, you can display the components by activating this column. You can see the location of the components.
If you are looking at the top side, you can activate the top one only and zoom in on the location of these components. From there, you would be able to tell what the lifetime of these components is. Sometimes, it's difficult to zoom in on bad sections.
The best way to do it is to use the second feature here, which is displaying the warnings and the errors. If everything is green, it is below the warning number. If it exceeds the warning number, you get yellow regions. If it exceeds the error number, it's red.
If you see any red spot, you can zoom in on it because it's really bad. The current density there is extremely high, and you need to find a way to reduce it.
In addition to this, you can also get a table that tells you about all the regions in your PCB that have less than a specific number of hours of operation. The location and the MTTF hours will be provided. The good thing about this table is that you can also zoom in on vias.
You can see the lifetime of every via in the PCB. It's very important to focus on the vias because they are the weakest element in a PCB structure. This will give you an idea of the lifetime of your PCB, whether the metals themselves, the components, and also the vias. Thank you.
