Have you ever gone to a used car dealership and tried to get a good deal on a car? It’s nearly impossible for anyone but a mechanic. When I went I ended up with a choice between two cars that seemed nearly identical to me, except for their price. I picked the cheaper one and took it to a local shop, and found out that I’d chosen a jalopy. Sometimes choosing PCB design software can feel the same way. You use a free program or spend some money on an intermediate one, just to find out it only goes half the distance you need it to. Before deciding on an electronic design automation (EDA) tool, you need to find out it if supports the advanced features necessary to design your board. It’s also important to be sure that all of these elements are available in a unified environment that can be customized to fit your specific needs.
Features to Look For
The reason I chose the car I did was simply the price. It looked the same as the other vehicle but cost a couple thousand less. It turns out that I got what I paid for, and that rings true for ECAD software as well. You probably want to use less expensive, or even free, software to design your PCB. The problem with the knock-off brand is it doesn’t come with all the bells and whistles, but as PCB design becomes more complex these “bells and whistles” are turning into necessities. Here are a few of the things to look for when choosing your design program.
Board Size - This one is pretty obvious, but I’ll mention it anyway. Lots of free tools are severely limited onboard space. Make sure your software supports enough space for your circuit.
Advanced Via Design - If you’re designing things like high density interconnect (HDI) boards or high-speed boards this is very important. You’ll need to use things like blind and buried vias, via-in-pads (VIPs), microvias, and back drilling. Support for these is not always included in lower-end software, so make sure you can use them if you need them.
Number of Layers - This one is a bit self-explanatory as well. Most free and nearly free tools limit the number of layers you can use. If your board is going to use lots of layers, you probably want to go for professional PCB design software.
Integrated software will ensure you don’t end up missing a piece.
3D Modeling - You may not think much about 3D modeling, just like how I don’t bother much about the inner workings of my car. However, 3D modeling can be very important for you, especially if you’re designing a PCB for embedded systems. You’ll need to make sure your board fits inside its enclosure. Great software will be able to import a model of your enclosure, generate a model of your circuit, and see if they fit together.
Power Delivery Network Analysis (PDNA) - PDNA used to be just for the power experts, but more and more you’ll find it’s important for you to do at least a little yourself. No one wants to learn how to use the signal analysis programs that make up the basis for PDNA. It’s much easier to find a program that can do this for you.
Differential Pair Routing - I often decide to try and navigate my car to my destination without a GPS. On a related note, I also frequently get lost. If you’re designing a board with differential pairs, good design software can be like a good GPS. You’ll need to route your differential traces to reduce length and preserve signal integrity. Cheap programs may let you route things yourself, but they won’t give you the help you need to find the best path possible.
This isn’t an exhaustive list, but it should give you an idea of the types of things you should look for in a good EDA tool.
Some people have a different car for every situation. A big truck for moving things around, an SUV for taking the family to the woods, and a sedan with good gas mileage for long trips. Unfortunately, I’m not rich enough for that and I have a small driveway. I prefer one car that does it all. This is what you should be looking for in PCB design software, an all-in-one solution. This will greatly reduce your headache and ensure that everything meshes together at the end of the day.
The funny thing about all the different free tools out there is that lots of them do different things well. Some have advanced functionality, but have such a steep learning curve that makes them hard to take advantage of. Others are easy to use but lack all the features you need. In addition, most of them lack peripheral tools like simulators and PDNA. It’s already a pain to learn the design software, so you don’t want to have to read up on 7 different analysis tools as well. It’s much easier to buy solid software that has everything included. I would identify what features you want, and then find software that has them all integrated.
The other side of the consolidated approach is that you can be sure everything will actually work. Lots of software can “plug in” different third-party tools. Sometimes that works, and sometimes you end up spending more time trying to fix the interlink than you do actually use the plugin. Additionally, there’s the possibility that the external tool doesn’t do what it’s supposed to and leads you to make inaccurate design changes. If one company has integrated everything into their program, it’s sure to work the first time. When your tools are all made by one developer that you trust, you can be confident in the results they provide.
Sometimes no one makes what you need. Customization will let you make it yourself. Editorial Credit: LandFox / Shutterstock.com
If there’s one thing car junkies love, it’s customization. If I’d been more into it maybe I could have souped up that clunker I bought. PCB designers love customizing as well. Even if you buy the absolute best design software out there, chances are that it won’t have extremely specific functionality that you need. At that point, the best tool you can get is one you can change.
Design software like Altium Designer comes with a software development kit (SDK) that lets you create your own tools. That way if you think of something revolutionary and don’t want to wait for a developer to implement it, you can do it yourself. That being said, Altium Designer should have nearly every tool you need. It includes all of the features mentioned above, and much more. Of course, they’re all available in a unified environment. No more clicking through different windows, trying to find where that waveform simulator went.
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