There is no doubt that when it comes to PCB design, placement of the components will take up the bulk of your time, but that doesn’t mean you can ignore the routing either. If you are new to the field then the whole thing can seem a bit overwhelming at first and that’s okay because the process can get quite complex to handle at times. Fortunately, there are a few tips which beginners can follow to make their initial routing endeavors a little less problematic.
Autorouters Are Not Always Accurate
Alluring as it may be, the autorouter won’t solve your routing issues like you were hoping it would. They do serve some key functions, but we will get to them later. Autorouters are often inaccurate and asymmetrical, therefore making them unreliable. You should do the routing manually to ensure quality and accuracy.
Autorouters Are Helpful Too!
While they cannot exactly be relied upon to complete the entire routing process by themselves, they can be used for the following purposes.
- Run it after placing your parts and check to see how you can improve the placements if the completion rating is below 85%.
- Runs made by the autorouter often let you see paths that you couldn’t see earlier.
- Autorouting can help in detecting bottlenecks, if there are any.
The first step is to have a chat with your manufacturer regarding the trace width, trace spacing and the number of layers. There’s both the question of your manufacturer’s capacity and your budget, so clear that part with them first, before designing something that isn’t practically feasible. Now that you know what you have to work with, it’s time to keep the following few points in mind while doing so.
- Wider traces will produce less heat so make them as wide as possible without crossing the previously decided maximums
- Power and ground traces will need to be wider than the rest to accommodate for the extra electricity which they handle
- The general recommendation is to leave at least a gap of 0.007” – 0.010” of space in-between every adjacent traces and pads on the PCB
- Leave a ring of space between mounting holes and traces, as well as other components
- Create a common ground plane on your board (a relatively large copper section) for all components
90-Degree Trace Angles Are Bad News
The big problem with 90-degree trace angles is that they could lead to short-circuits because more often than not, the outside corner of a right-angled trace is etched narrower than the rest of it, which increases heat generation. Go with 45-degree angles instead.
Vias serve two important functions and you should use them accordingly to get the best out of your PCB design.
- Vias are perfect for facilitating electrical connectivity between the separate layers on your board.
- They can also be used to transfer heat from one section of the board to the other, which is useful when you have a particularly power-hungry component on the board.
While these tips should help you in getting started, they cannot be put into action without a proper and reliable PCB layout software with features such as schematic capture, 3D simulation and centralized component management among others. Companies such as Altium.com have all the necessary design tools and a massive parts library that keeps getting updated in real time, so be sure to visit them before getting started.