PRINTED CIRCUIT BOARDS What’s involved in the process of PCB design?
Printed circuit boards (PCBs) are the backbone of modern electronics. Everything from smartphones to cars wouldn’t work without a functioning PCB, so designing one is sensitive work. Here’s a closer look at what’s involved.
Creating the schematic
The first step in designing a PCB is creating a schematic for the circuit. This will be the blueprint for the conductive pathways that carry electrical signals throughout the board. While designers can make any necessary changes later, the more accurate this layout is, the easier the rest of the process will be.
The PCB’s end-use will influence the circuit schematic as much as what the PCB must accomplish. For example, some advanced electronics use multilayer PCBs to fit more components in a given space. When working with these kinds of circuits, the schematic needs to consider how different signals travel between layers.
Some design programs have built-in checking features that highlight possible errors at this stage. Otherwise, designers should frequently recheck their work to ensure their schematic doesn’t introduce any electrical problems.
After designing the basic circuit, PCB manufacturers outline where different components will go on the board. As they introduce more elements into the design, they’ll get a better idea of how big the PCB should be or if they should add any layers. This will also highlight any potential problems in the circuit schematic they missed earlier.
Components should fall into different sections according to what they do. Grouping these elements is crucial because the parts in each area should be close together. The traces can pick up electromagnetic radiation if they're too far apart, interfering with the signal.
The next step in designing a PCB is to route the connections between all the components. They must adhere to reliability standards under IPC-9252, so ensuring they work correctly in the design phase is crucial. This step can be time-consuming, so designers sometimes automate it.
Auto-routing features are relatively standard in PCB software today, but they’re not ideal for complicated circuits. Automated solutions don’t always find the best path for the PCB’s end-use considerations and may introduce errors. Still, many designers use them to save time, auto-routing first before making any necessary manual adjustments.
Defining the PCB outline
Once all the circuitry and component layouts are finished, designers define the board’s outline. While this step may be straightforward compared to others, it often entails more thought than one would think. Drawing PCB outlines goes beyond choosing a shape. Designers must consider factors like board materials, end-use and potential interference.
For example, a PCB won’t always be the rigid, plastic board most people are familiar with. Several tech companies have recently announced rollable smartphones, which would require flexible PCBs. Designers behind these devices must define an outline that can work in an elastic material and account for potential pinch points.
Checking for defects
The final step in designing a PCB, like in most design operations, is to check it for flaws. It’s far more affordable to fix a digital layout than to interrupt production, so designers must have a thorough review process. In most modern PCB manufacturing settings, this involves a manual and automated check.
Most, if not all, PCB design programs include a design rule check feature. This will automatically highlight potential errors that could hinder the board’s functionality. After looking through these suggestions, designers will pass the file to another party to review it manually to catch any other mistakes.
After the final check, manufacturers can pass their PCB designs on to bring them into reality.
Designing a PCB is an involved process
PCBs are some of the most crucial electronics components in modern devices, so it’s no surprise that their design phase can be complex. While it may seem intense, being thorough in all these steps ensures less work down the line. Electronics manufacturers can then be sure their products work as intended.