Signal Integrity Simulations to Determine EMI Board Performance
One of the fastest ways to evaluate your board’s performance in terms of EMI (and therefore electromagnetic compatibility) is to perform a quick simulation of your design.
This is one of those steps that should be integrated into your project schedule when your projects become fairly complex, and for fun, even when they are not. It does not require the physical board to be ready, allowing you to quickly adjust the layout and achieve a much better-performing design.
Contrary to what many still believe, the simulation process is very fast.
To simulate signal integrity, it only takes a few minutes with a powerful tool like Simbeor. Simply export your project in ODB++ format, enter your signal parameters, and you’ll immediately see how your board performs.
In this particular case, I’m preparing for a new EMC/EMI video on Minima, a powerful open-source carrier board designed by Pierluigi Colangeli for the Raspberry Pi Compute Module.
I start with what I call an eagle-eye design review of the project files, writing down potential issues, and once that process is complete, I run a Simbeor simulation to verify those points and ensure no other problems are being overlooked.
These steps are part of the overall EMC compliance process, ensuring that when you go to the EMC lab, you do so with confidence instead of simply hoping for the best.
If any mistakes are found at this stage, you can correct them, re-run the simulation, and verify again. Once the remaining steps are complete, you can move to production and confirm your results with real tests.
This process dramatically reduces the chances of errors while speeding up execution.
In the traditional approach, you would have to design, produce, and test repeatedly, often spending months or even years before finally getting it right for EMC.
With this new process, you gain a real competitive advantage.
The only caveat is that you must know what to look for.
But that’s nothing to worry about, because we’ve got you covered with our professional courses at fresuelectronics.com/
To electromagnetic enlightenment,
Dario
P.S. We just launched new course bundles that can save you thousands of euros for you or your team. Check the link above to apply now.
So many companies are wasting piles of cash on FCC certifications and EMC tests.
Yes, they’re required, and yes, they’re expensive, but that’s not why the money is being wasted.
They waste it because their EMC/EMI design and review process is off track, and as a result, their projects struggle to pass these tests.
Many companies already have a process in place, but they either apply it too late or it simply isn’t effective.
On top of that, many have review committees that lack the right expertise, or engineers who were never properly trained to handle EMI problems.
Traditional university programs, a shiny “electronic engineer” title, or even years of field experience are often not enough when it comes to EMI design.
The outcome? Endless back and forth between the test bench and the EMC lab. Projects stall before they even hit the market.
Smart teams recognize this as a knowledge issue, and they take action to fix it once and for all.
Boom. Move on.
Less-performing teams, instead, keep chasing quick fixes, last-minute filter patches, and random “tips” from the internet.
Those rarely solve the problem (sometimes they make it even worse) and the team ends up stuck in the same loop.
Cash keeps burning.
Careers stop growing.
Sad.
Does it have to be this way? Nope.
EMC and EMI are science, not black magic.
You just need the right training and system in place from the start, so that results become predictable and repeatable.
Your competitors are already doing that.
That’s why they get faster certifications, lower costs, and products that work right the first time.
If you or your team want to get there, start by mastering EMI control principles, begin with our trainings here: fresuelectronics.com/trainings
To electromagnetic enlightenment,
Dario
P.S. We just launched new course bundles that can save you thousands of euros for you or your team. Check the link above to apply now.
Screenshot from a PC board I reviewed a few days ago for a client.
The client was told that the GND tracks were necessary to pass EMC tests.
Notice that this is a reference design, so the client didn’t even doubt that it was going to work.
And that is exactly the problem.
You can’t just trust — you need to verify.
The idea here is that by placing a GND track adjacent to the signal trace, it’s going to “sink” or “shield” EMI.
But that’s not what EM fields care about.
For all they care, you could call that trace Mickey Mouse.
The fallacy of the “electrons flowing through copper” model is what keeps you stuck there.
And it’s also what stops you from understanding EMI control in depth.
To really get it, you need to switch perspective and start visualizing traces as merely the boundaries of the fields.
This also means that when you design the PCB, you change your design approach and start seeing things in terms of displacement current, impedance, electric and magnetic fields, and conduction current.
Then, a picture like that will immediately ring the bells and point you toward inductance — and the problems it will create in terms of EMC and EMI control.
To electromagnetic enlightenment,
Dario
By the way, if you want to feel confident about taking your device for an EMC test — knowing you did things the right way, without having to keep your fingers crossed every time, and actually become the point of contact for EMC and EMI in your company, then check out my trainings and courses at fresuelectronics.com/
Especially today, we introduced the Startup and Enterprise Package for small and large teams, where you can get thousands of €€€ in discounts when you purchase the course for you and your team.
I’ve never met a highly successful (and well paid) electronic engineer who hadn’t mastered EMI control.
Not one.
Every great engineer I’ve known had a solid understanding of electromagnetic fields. And I’m not talking about memorizing Maxwell’s equations, I’m talking about knowing how to control and guide EM fields in their circuits.
And the proof? Their circuits passed EMC testing on the very first try.
Yet so many designers still treat EMC as if it were black magic instead of science.
They get intimidated by complex equations shared by “experts,” which are often just academic showpieces, and rarely used in real-world EMI control engineering.
If EMC and EMI control still feel intimidating, or if you’re struggling to pass EMC tests, this crash course is for you.
This free course includes lessons and materials taken directly from our premium professional programs at fresuelectronics.com.
We’re giving it away for two reasons:
- To show you why many electronic products fail EMC tests before they even reach the lab
- To give you a clear preview of our professional courses so you can see if they’re right for you
If you’re serious about mastering EMC/EMI design and professional circuit board design, our full courses can help you take your skills, and your career, to the next level.
We hope this course gives you a strong foundation in how top engineers design reliable, high-performance electronic products.
Our goal is simple: to help you design circuits that work the first time, and grow in your engineering career.
No wonder passing EMC tests on the first try often feels impossible.
We build our electronics foundation by thinking of circuits using the wrong analogies. When these analogies seem correct, the explanations from experts are often so complex that most people give up trying to truly understand them.
The result is that we continue designing circuits incorrectly, not because we lack skill, but because we learned outdated models that no longer match modern technological requirements and constraints.
The sooner you move away from these outdated models, the sooner you can replace them with an intuitive understanding of how electromagnetic fields behave. This understanding becomes a natural law and a logical way of thinking.
Every highly successful company has someone who has mastered EMI control, at least to some degree.
It is almost inevitable.
Without it, your designs may work for a while, but once budgets, constraints, and risks increase, problems will appear.
The surprising part is that this knowledge is not new, it is a different perspective. Engineers such as Steinmetz, Tesla, Heaviside, and others have written about it, but over time, this view of electromagnetic fields was lost in favor of oversimplified models that worked only up to a point.
Today, we are building state-of-the-art technologies, products, and devices. If we want to be at the top of our industry (both as businesses and as engineers) we must master EMI control and printed circuit board design that channels and contains electromagnetic fields effectively.
After years of applications and research, I have compiled the best proven concepts of EMI control so that designing for EMI becomes as straightforward as following a checklist.
If you are serious about making EMC issues and poor PCB design a thing of the past, check my courses and guides here: fresuelectronics.com/
Facing an EMC test is one of the most stressful moments for any electronic engineer.
It’s that nerve-wracking time when your design, which has worked flawlessly until now, is put under the toughest scrutiny. You’re waiting for the report, pass or fail, or, if you’re at the lab, you watch the results live while your heart pounds like a drum roll.
This is the moment when ego, pride, and months of work are on the line.
Because it’s not just about you.
The whole team is behind you, but you’re the face of the design.
Failure is simply not an option. The budget won’t allow another failed EMC test. Neither will the project stakeholders, who are already pushing to launch the product.
And yet, here’s the truth: most engineers were never properly taught how to design with EMC in mind.
At school, we learned equations that seemed disconnected from real-world PCB design. We fell back to outdated classical circuit theory, building like plumbers with pipes instead of engineers working with electromagnetic fields.
We were told that understanding EM fields requires a PhD in math. That EMC is “too complex”, almost like black magic.
But it doesn’t have to be this way.
That’s why we created the EMC/EMI Design Course.
This course was built by engineers, for engineers. No fluff, no theory that never translates to practice. Instead, you’ll get:
- A clear, practical method to design boards that pass EMC faster.
- Tools, techniques, and strategies you can apply immediately in your projects.
- A proven system that eliminates costly trial-and-error fixes and unpractical last-minute patches.
This is real engineering knowledge you’ll use every day, from design to lab testing to final compliance.
If you’re ready to stop fearing EMC tests and start controlling EMI with confidence, click below and join the course today.
Random PCB net naming is not just a source of confusion for the whole team, it also leads to mistakes and slows down the design process.
And yes, the whole team is affected. Not only the designers, but also those who test, review, and debug the board will feel the impact.
That’s why assigning clear and consistent net names is so important.
It allows the layout engineer to route traces correctly, following the intent set in the schematics. It’s one of those small details that matter far more than they might seem at first.
When reviewing a board, a clear net name makes it instantly obvious what’s being inspected. When debugging, it speeds up troubleshooting. And even months later, when you revisit the design, proper naming helps you immediately understand where to continue from.
I no longer take this for granted, especially since tools like net ties make it easy to combine different net names for the same conductor while still respecting different requirements (for example, sensing nets).
It's a quick improvement to your design that gives you massive returns.
Try this yourself on your next design.
To electromagnetic enlightenment,
Dario
P.S. If you want a solid project to learn from and dive into professional PCB design, in the course link below I will walk you through the full design process and the principles behind building a professional PCB from scratch. Enroll in the course here: fresuelectronics.com/pcb-design-course
Electromagnetic Fields in PCB Design: Master EMI Control for EMC Compliance
In this video, I’m going to reveal one of the most critical concepts for controlling electromagnetic interference (EMI) in printed circuit board (PCB) design.
By learning how to visualize and manage electromagnetic fields, you can ensure your PCB passes EMC tests faster, with fewer surprises, and at a lower cost.
Key takeaways:
- Understand how electric and magnetic fields behave in PCBs.
- Discover the importance of the return reference plane in containing fields.
- Learn why proper PCB stack-up design is essential to avoid EMI issues.
- Explore practical visualizations and simulations to master field containment.
This is one of the lessons of the self-paced online course EMC/EMI Design Course for Professionals.
P.S. This lesson is provided to you free of charge so that once you are ready to get your skills to the next level, you can simply enrol in the full course here: fresuelectronics.com/emi-design-course
Lately, more and more ECUs (Electronic Control Units) have been landing on my bench.
Nothing to worry about with EMC/EMI… at least, that’s the hope :)
Even though some of these designs are decades old, from what I can see, the layout of the outer layers shows that good EMI control strategies were applied.
Designing complex projects like this one, or the DF_ESC High-Power Motor Controller (more about it later), is never trivial.
Layout choices, partitioning and placement, return and reference strategies, and layer stack-up all play a significant role.
As they say, in professional PCB design the devil is in the details.
Mess up your stack-up design, and you can find yourself locked into multiple project respins before you successfully pass EMC testing. Not to mention the time wasted debugging where EMI problems come from, along with the headache of signal integrity issues.
The challenge is always there.
That’s why we care about understanding the source of the problem, not simply applying quick fixes.
Engineering is mostly about taking the right preventive measures and making proper considerations from the start.
Of course, this becomes far easier when you have a tested process you can rely on.
To electromagnetic enlightenment,
Dario
P.S. If you want a solid project to learn from and dive into professional PCB design, in the course link below I will walk you through the full design process and the principles behind building a professional PCB from scratch. Enroll in the course here: fresuelectronics.com/pcb-design-course
Crowded Vias in Your PCB Design? Double-Check for EMI Control
This is one of those issues that looks innocent at first, but in many cases, it’s not.
So, what’s happening here?
The designer of this board routed the differential pairs and added Return Reference Vias (RRVs) to contain the EM fields of the signal during vertical propagation, in other words, when going from one layer to another in the stackup.
That’s great! It’s already one of those nice touches that can prevent big EMC failures later on.
But here’s the catch: by applying this technique, the via placement became a bit crowded near the differential pair vias.
Since these vias are connected to the Return and Reference Plane (RRP), when we analyze that plane everything looks fine.
However, if we look at the other plane, in this case the power plane, which is not connected to these vias or to the differential pair vias, we find that a large hole has been created in the plane.
Why is this a problem?
One issue with this large gap is that current cannot flow directly through this portion of the plane. Because of the hole, the current is forced to detour and find another path to its destination.
Detours create two potential problems:
- They can increase the size of the current loop. A larger enclosed loop area often means higher emissions.
- The current is forced away from its preferred path, which can bring it closer to other signal traces, increasing the risk of crosstalk with other nets.
A quick fix is to keep using RRVs, but space the vias properly so that the plane remains more continuous. Smaller holes mean more copper area for the current to flow through.
This simple step can save you from a costly board respin caused by EMI or signal integrity issues.
To electromagnetic enlightenment,
Dario
P.S. If you’re still unsure how to put these concepts into practice and are serious about mastering EMI control, join my free crash course here: fresuelectronics.com/
Dario Fresu
Signal Integrity Simulations to Determine EMI Board Performance
One of the fastest ways to evaluate your board’s performance in terms of EMI (and therefore electromagnetic compatibility) is to perform a quick simulation of your design.
This is one of those steps that should be integrated into your project schedule when your projects become fairly complex, and for fun, even when they are not. It does not require the physical board to be ready, allowing you to quickly adjust the layout and achieve a much better-performing design.
Contrary to what many still believe, the simulation process is very fast.
To simulate signal integrity, it only takes a few minutes with a powerful tool like Simbeor. Simply export your project in ODB++ format, enter your signal parameters, and you’ll immediately see how your board performs.
In this particular case, I’m preparing for a new EMC/EMI video on Minima, a powerful open-source carrier board designed by Pierluigi Colangeli for the Raspberry Pi Compute Module.
I start with what I call an eagle-eye design review of the project files, writing down potential issues, and once that process is complete, I run a Simbeor simulation to verify those points and ensure no other problems are being overlooked.
These steps are part of the overall EMC compliance process, ensuring that when you go to the EMC lab, you do so with confidence instead of simply hoping for the best.
If any mistakes are found at this stage, you can correct them, re-run the simulation, and verify again. Once the remaining steps are complete, you can move to production and confirm your results with real tests.
This process dramatically reduces the chances of errors while speeding up execution.
In the traditional approach, you would have to design, produce, and test repeatedly, often spending months or even years before finally getting it right for EMC.
With this new process, you gain a real competitive advantage.
The only caveat is that you must know what to look for.
But that’s nothing to worry about, because we’ve got you covered with our professional courses at fresuelectronics.com/
To electromagnetic enlightenment,
Dario
P.S. We just launched new course bundles that can save you thousands of euros for you or your team. Check the link above to apply now.
1 day ago | [YT] | 14
View 0 replies
Dario Fresu
So many companies are wasting piles of cash on FCC certifications and EMC tests.
Yes, they’re required, and yes, they’re expensive, but that’s not why the money is being wasted.
They waste it because their EMC/EMI design and review process is off track, and as a result, their projects struggle to pass these tests.
Many companies already have a process in place, but they either apply it too late or it simply isn’t effective.
On top of that, many have review committees that lack the right expertise, or engineers who were never properly trained to handle EMI problems.
Traditional university programs, a shiny “electronic engineer” title, or even years of field experience are often not enough when it comes to EMI design.
The outcome? Endless back and forth between the test bench and the EMC lab. Projects stall before they even hit the market.
Smart teams recognize this as a knowledge issue, and they take action to fix it once and for all.
Boom. Move on.
Less-performing teams, instead, keep chasing quick fixes, last-minute filter patches, and random “tips” from the internet.
Those rarely solve the problem (sometimes they make it even worse) and the team ends up stuck in the same loop.
Cash keeps burning.
Careers stop growing.
Sad.
Does it have to be this way? Nope.
EMC and EMI are science, not black magic.
You just need the right training and system in place from the start, so that results become predictable and repeatable.
Your competitors are already doing that.
That’s why they get faster certifications, lower costs, and products that work right the first time.
If you or your team want to get there, start by mastering EMI control principles, begin with our trainings here: fresuelectronics.com/trainings
To electromagnetic enlightenment,
Dario
P.S. We just launched new course bundles that can save you thousands of euros for you or your team. Check the link above to apply now.
3 days ago | [YT] | 11
View 0 replies
Dario Fresu
Screenshot from a PC board I reviewed a few days ago for a client.
The client was told that the GND tracks were necessary to pass EMC tests.
Notice that this is a reference design, so the client didn’t even doubt that it was going to work.
And that is exactly the problem.
You can’t just trust — you need to verify.
The idea here is that by placing a GND track adjacent to the signal trace, it’s going to “sink” or “shield” EMI.
But that’s not what EM fields care about.
For all they care, you could call that trace Mickey Mouse.
The fallacy of the “electrons flowing through copper” model is what keeps you stuck there.
And it’s also what stops you from understanding EMI control in depth.
To really get it, you need to switch perspective and start visualizing traces as merely the boundaries of the fields.
This also means that when you design the PCB, you change your design approach and start seeing things in terms of displacement current, impedance, electric and magnetic fields, and conduction current.
Then, a picture like that will immediately ring the bells and point you toward inductance — and the problems it will create in terms of EMC and EMI control.
To electromagnetic enlightenment,
Dario
By the way, if you want to feel confident about taking your device for an EMC test — knowing you did things the right way, without having to keep your fingers crossed every time, and actually become the point of contact for EMC and EMI in your company, then check out my trainings and courses at fresuelectronics.com/
Especially today, we introduced the Startup and Enterprise Package for small and large teams, where you can get thousands of €€€ in discounts when you purchase the course for you and your team.
4 days ago | [YT] | 11
View 1 reply
Dario Fresu
I’ve never met a highly successful (and well paid) electronic engineer who hadn’t mastered EMI control.
Not one.
Every great engineer I’ve known had a solid understanding of electromagnetic fields. And I’m not talking about memorizing Maxwell’s equations, I’m talking about knowing how to control and guide EM fields in their circuits.
And the proof? Their circuits passed EMC testing on the very first try.
Yet so many designers still treat EMC as if it were black magic instead of science.
They get intimidated by complex equations shared by “experts,” which are often just academic showpieces, and rarely used in real-world EMI control engineering.
If EMC and EMI control still feel intimidating, or if you’re struggling to pass EMC tests, this crash course is for you.
This free course includes lessons and materials taken directly from our premium professional programs at fresuelectronics.com.
We’re giving it away for two reasons:
- To show you why many electronic products fail EMC tests before they even reach the lab
- To give you a clear preview of our professional courses so you can see if they’re right for you
If you’re serious about mastering EMC/EMI design and professional circuit board design, our full courses can help you take your skills, and your career, to the next level.
We hope this course gives you a strong foundation in how top engineers design reliable, high-performance electronic products.
Our goal is simple: to help you design circuits that work the first time, and grow in your engineering career.
👉 Get free access to the course here: fresuelectronics.com/
Let’s get started.
To electromagnetic enlightenment,
Dario
P.S. Spots are limited, and a qualification process applies.
5 days ago | [YT] | 19
View 0 replies
Dario Fresu
What Classical Circuit Theory Fails to Teach You
No wonder passing EMC tests on the first try often feels impossible.
We build our electronics foundation by thinking of circuits using the wrong analogies. When these analogies seem correct, the explanations from experts are often so complex that most people give up trying to truly understand them.
The result is that we continue designing circuits incorrectly, not because we lack skill, but because we learned outdated models that no longer match modern technological requirements and constraints.
The sooner you move away from these outdated models, the sooner you can replace them with an intuitive understanding of how electromagnetic fields behave. This understanding becomes a natural law and a logical way of thinking.
Every highly successful company has someone who has mastered EMI control, at least to some degree.
It is almost inevitable.
Without it, your designs may work for a while, but once budgets, constraints, and risks increase, problems will appear.
The surprising part is that this knowledge is not new, it is a different perspective. Engineers such as Steinmetz, Tesla, Heaviside, and others have written about it, but over time, this view of electromagnetic fields was lost in favor of oversimplified models that worked only up to a point.
Today, we are building state-of-the-art technologies, products, and devices. If we want to be at the top of our industry (both as businesses and as engineers) we must master EMI control and printed circuit board design that channels and contains electromagnetic fields effectively.
After years of applications and research, I have compiled the best proven concepts of EMI control so that designing for EMI becomes as straightforward as following a checklist.
If you are serious about making EMC issues and poor PCB design a thing of the past, check my courses and guides here: fresuelectronics.com/
To electromagnetic enlightenment,
Dario
6 days ago | [YT] | 13
View 0 replies
Dario Fresu
Facing an EMC test is one of the most stressful moments for any electronic engineer.
It’s that nerve-wracking time when your design, which has worked flawlessly until now, is put under the toughest scrutiny. You’re waiting for the report, pass or fail, or, if you’re at the lab, you watch the results live while your heart pounds like a drum roll.
This is the moment when ego, pride, and months of work are on the line.
Because it’s not just about you.
The whole team is behind you, but you’re the face of the design.
Failure is simply not an option. The budget won’t allow another failed EMC test. Neither will the project stakeholders, who are already pushing to launch the product.
And yet, here’s the truth: most engineers were never properly taught how to design with EMC in mind.
At school, we learned equations that seemed disconnected from real-world PCB design. We fell back to outdated classical circuit theory, building like plumbers with pipes instead of engineers working with electromagnetic fields.
We were told that understanding EM fields requires a PhD in math. That EMC is “too complex”, almost like black magic.
But it doesn’t have to be this way.
That’s why we created the EMC/EMI Design Course.
This course was built by engineers, for engineers. No fluff, no theory that never translates to practice. Instead, you’ll get:
- A clear, practical method to design boards that pass EMC faster.
- Tools, techniques, and strategies you can apply immediately in your projects.
- A proven system that eliminates costly trial-and-error fixes and unpractical last-minute patches.
This is real engineering knowledge you’ll use every day, from design to lab testing to final compliance.
If you’re ready to stop fearing EMC tests and start controlling EMI with confidence, click below and join the course today.
👉 fresuelectronics.com/emi-design-course
Don’t let another project be at risk. Master EMI control once and for all.
To electromagnetic enlightenment,
Dario
1 week ago | [YT] | 17
View 0 replies
Dario Fresu
Random PCB net naming is not just a source of confusion for the whole team, it also leads to mistakes and slows down the design process.
And yes, the whole team is affected. Not only the designers, but also those who test, review, and debug the board will feel the impact.
That’s why assigning clear and consistent net names is so important.
It allows the layout engineer to route traces correctly, following the intent set in the schematics. It’s one of those small details that matter far more than they might seem at first.
When reviewing a board, a clear net name makes it instantly obvious what’s being inspected. When debugging, it speeds up troubleshooting. And even months later, when you revisit the design, proper naming helps you immediately understand where to continue from.
I no longer take this for granted, especially since tools like net ties make it easy to combine different net names for the same conductor while still respecting different requirements (for example, sensing nets).
It's a quick improvement to your design that gives you massive returns.
Try this yourself on your next design.
To electromagnetic enlightenment,
Dario
P.S. If you want a solid project to learn from and dive into professional PCB design, in the course link below I will walk you through the full design process and the principles behind building a professional PCB from scratch. Enroll in the course here: fresuelectronics.com/pcb-design-course
1 week ago | [YT] | 8
View 0 replies
Dario Fresu
Electromagnetic Fields in PCB Design: Master EMI Control for EMC Compliance
In this video, I’m going to reveal one of the most critical concepts for controlling electromagnetic interference (EMI) in printed circuit board (PCB) design.
By learning how to visualize and manage electromagnetic fields, you can ensure your PCB passes EMC tests faster, with fewer surprises, and at a lower cost.
Key takeaways:
- Understand how electric and magnetic fields behave in PCBs.
- Discover the importance of the return reference plane in containing fields.
- Learn why proper PCB stack-up design is essential to avoid EMI issues.
- Explore practical visualizations and simulations to master field containment.
This is one of the lessons of the self-paced online course EMC/EMI Design Course for Professionals.
Watch the lesson here: https://youtu.be/U0i3vFoIKlk?si=AsRi1...
To electromagnetic enlightenment,
Dario
P.S. This lesson is provided to you free of charge so that once you are ready to get your skills to the next level, you can simply enrol in the full course here: fresuelectronics.com/emi-design-course
2 weeks ago | [YT] | 7
View 0 replies
Dario Fresu
Lately, more and more ECUs (Electronic Control Units) have been landing on my bench.
Nothing to worry about with EMC/EMI… at least, that’s the hope :)
Even though some of these designs are decades old, from what I can see, the layout of the outer layers shows that good EMI control strategies were applied.
Designing complex projects like this one, or the DF_ESC High-Power Motor Controller (more about it later), is never trivial.
Layout choices, partitioning and placement, return and reference strategies, and layer stack-up all play a significant role.
As they say, in professional PCB design the devil is in the details.
Mess up your stack-up design, and you can find yourself locked into multiple project respins before you successfully pass EMC testing. Not to mention the time wasted debugging where EMI problems come from, along with the headache of signal integrity issues.
The challenge is always there.
That’s why we care about understanding the source of the problem, not simply applying quick fixes.
Engineering is mostly about taking the right preventive measures and making proper considerations from the start.
Of course, this becomes far easier when you have a tested process you can rely on.
To electromagnetic enlightenment,
Dario
P.S. If you want a solid project to learn from and dive into professional PCB design, in the course link below I will walk you through the full design process and the principles behind building a professional PCB from scratch. Enroll in the course here: fresuelectronics.com/pcb-design-course
2 weeks ago | [YT] | 16
View 0 replies
Dario Fresu
Crowded Vias in Your PCB Design? Double-Check for EMI Control
This is one of those issues that looks innocent at first, but in many cases, it’s not.
So, what’s happening here?
The designer of this board routed the differential pairs and added Return Reference Vias (RRVs) to contain the EM fields of the signal during vertical propagation, in other words, when going from one layer to another in the stackup.
That’s great! It’s already one of those nice touches that can prevent big EMC failures later on.
But here’s the catch: by applying this technique, the via placement became a bit crowded near the differential pair vias.
Since these vias are connected to the Return and Reference Plane (RRP), when we analyze that plane everything looks fine.
However, if we look at the other plane, in this case the power plane, which is not connected to these vias or to the differential pair vias, we find that a large hole has been created in the plane.
Why is this a problem?
One issue with this large gap is that current cannot flow directly through this portion of the plane. Because of the hole, the current is forced to detour and find another path to its destination.
Detours create two potential problems:
- They can increase the size of the current loop. A larger enclosed loop area often means higher emissions.
- The current is forced away from its preferred path, which can bring it closer to other signal traces, increasing the risk of crosstalk with other nets.
A quick fix is to keep using RRVs, but space the vias properly so that the plane remains more continuous. Smaller holes mean more copper area for the current to flow through.
This simple step can save you from a costly board respin caused by EMI or signal integrity issues.
To electromagnetic enlightenment,
Dario
P.S. If you’re still unsure how to put these concepts into practice and are serious about mastering EMI control, join my free crash course here: fresuelectronics.com/
*Qualifications apply.
2 weeks ago | [YT] | 12
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