PCB design can be very overwhelming for those who are just starting out in this industry. Where do you place the components? How do you create an effective schematic? There are so many things to think about and when you don’t have much experience things can go wrong very quickly.
To help you with this, we have put together some PCB design tips for beginners. Keep reading if you would like to find out more.
Contents
Think About Width Traces
In PCB design, the width traces are very important and so you need to spend some time figuring them out. If you want to be able to control the amount of heat that flows through your PCB then you need to make sure that the traces are the correct width. For beginners, we suggest taking a look online at some guidance on the right width of your traces. Don’t skip this step as it will only cause you problems when your circuit board raises in temperature.
Invest In PCB Design Software
The best printed circuit board designs are those created using the advanced technology that is available. PCB design software now comes with all of the features that beginners need to get started as well as the advanced tools that experienced designers require. With PCB design software, you can create your schematic, compare it to your design and search an extensive component library for all of the right parts. Make sure to invest in the right software for your project and you’ll be able to ease yourself into PCB design.
Avoid 90 Degree Trace Angles
Our next PCB design tip for beginners is that you should try to avoid using 90-degree trace angles in your design. This piece of advice is very important, and it is something which a lot of designers swear by. You need to make sure that all of your traces are etched fully and when you have a 90-degree angle, you are risking this not happening. Try to use 45-degree angles on your traces and you will find that it works much more effectively.
The Ground Plane
Our final tip for those who are just starting out in PCB design is to always remember to create a ground plane. This is important in many different types of electronics as you can easily make sure that your voltage is right. If you avoid this, you will end up with various different ground connections across your boards and each will come with their own voltage drops and resistance values. Remember to create a ground plane and you’ll see how your design is improved.
Final Verdict
If you are a beginner in PCB design, then you should make sure to take all of our advice on board. Think about investing in the right software package for your project and make sure that you are utilising the best tools on the market right now. Soon, you’ll be an experienced PCB designer with plenty of projects under your belt.
It’s clear barely any research was done in writing this article. Since I’m a software and hardware engineer
I can help shed some light on the 4 points mentioned and offer some tips along with it.
* PCB trace width can be a factor. That’s certainly true, but even a trace of 0.254mm wide can handle 1Amp of current and only rise 10°C approximately in temperature. There are exceptions that require extra consideration like; USB differential pairs, power trace width and tin-plating, and high-frequency traces/planes. Having said that, using wider traces and placed farther apart gives the manufacturer some margins for error. Tight margins means more overhead in keeping your super-duper-complex layout in check which translate into higher costs.
* It’s true that good design tools can be costly, but they come with a guarantee it’ll contain all the tools you’ll ever need. If you can afford such a design suite, great. But if you’re a beginner on a budget then there are excellent free schematic/PCB design tools available like EasyEDA or KiCad (I’m not affiliated). Even Autodesk’s Fusion360 comes with Eagle embedded nowadays. It’s free for personal use only, but if for the hobbyist not making any profit this is an amazing tool to use.
* The 90-degree angle thing is a left-over from the early days of PCB manufacturing. It’s true this is advice “a lot of designers swear by”, but that doesn’t make it sound advice. From what I recall, back in the days, 90-degree angles or less cause acid-traps where the etching solution would get trapped and etched more than necessary. As you might imagine, this can cause all sorts of problems from; shorts between traces, or open-circuits, or impedance and resistance issues. Using 45-degree angles would solve the problem. Let’s put it this way; when you ask old-school veterans for advice, odds are you get old-school advice. The chemistry has improved quite a lot the past few decades and 90-degree angles are no longer a problem for etching.
Having that said, acid traps are still something to be aware of. Acute angles and small corners can still cause etching problems in modern manufacturing. My rule-of-thumb is to avoid acute angles. These happen when a trace at a 45-degree slope intersects a straight trace. One side has a 135-degree angle(which is fine), but the other side has a 45-degrees point. That 45-degree spot might become an acid trap. Who knows, perhaps acid traps will become a thing of the past one day.
This 90-degree rule has sparked a lot of debate and resulted in a lot of testing being done. This concern is not entirely without merit. Some engineers argue that 90-degree angles cause additional electromagnetic interference(EMI). As far as I’m aware, this is a potential problem at frequency up into the gigahertz range. If you’re designing a PCB with low speed serial communication you don’t have to worry about your 90-degree traces causing unwanted EMI.
I have colleagues argue about the space required for 45-degree traces is more than using 90-degree angles due to it’s geometry(square-root of 2). Whether this is nit-picking or not, I don’t really care. It makes sense to use your knowledge when drawing traces in tight areas. Use 90-degree angles when it makes sense. To me, I use 45-degree angles for cosmetic reasons. I find it looks neater.
* Good advice, but where do you place your ground plane? What about a power plane? What about 2 vs 4+ layer PCB’s? Using ground and supply planes have various benefits. Just like drawing your schematic, you can pluck your globally accessible nets(power and ground for example) “out of the air” by using a via. This leaves more room for signal traces to take routes that would otherwise not be possible. Mind you, via’s result in two 90-degree angles. As mentioned in the article, when you go insane with ground traces and avoid using a plane there’s a risk trace resistance might offset your ground references. Whether this is a problem solely depends on the components used. For example a microcontroller(megaAVR, ESP32, etc.) rely on proper referencing to reliably perform analog operations.
Using planes for power and ground comes with a few consequences. It increases the overall PCB capacitance, increase EMC(electromagnetic compatibility), and keeps the PCB pretty much straight during reflow or a vapor-phase session. Of course, the latter has more variables associated to it. And if you’re soldering by hand then never mind. Whether any of these are good or bad depends on the application of your board. But since this article is targeted at beginners, consider these to be a good thing in general.
Copper plane placement is definitely worthy of some consideration. For 2-layer boards it might be good practice to place the ground plane on top and the power supply on the bottom. Imagine someone scraping the soldermask on your board by accident and discover it has 24 Volts(perhaps more..) on it conducting through the body to ground via the hands or feet. Could be unpleasant, indeed. In other words, put the power plane on the least likely accessed location. You can’t prevent it all, but you can make your PCB a lot safer by implementing a simple design choice.
With 4-layer boards the issue mentioned above is pretty much eradicated. Your top and bottom become signal layers, the two inner layers become ground and power. Even in this situation ground is usually put near the top side, but usually for proper ground referencing for signal traces. This is most critical for radio frequency and USB signals.
* When starting out as a designer, I can’t hurt asking for advice and tips. Use the ones that make the most sense to you. Also consider contacting PCB manufacturers or assembly factories. They can offer loads of insight on the production cycle and issues they stumble upon. It might be some of the issues they experience is due to your design choices.
For example; You decided to place a bunch of SMT resistors too close together. On paper all seems fine, but it turns out the factory’s SMT machine has great difficulty placing your resistors that close together. They have to adjust them by hand resulting in increased manufacturing cost. Or another important one; you forgot to place panel and/or board fiducials. This might cause automated inspection (AOI) or pick&place (SMT machine placement) problems. Again increasing production time, thus also cost.
I hope this will help someone out there. Cheers.