When talking about printed circuit boards, novices often confuse “PCB schematic diagram” with “PCB design document”, but in fact they refer to different things. Understanding the differences between them is the key to successful PCB manufacturing, so in order for beginners to do this better, this paper will break down the key differences between PCB schematic diagram and PCB design.
What is PCB?
Before getting into the difference between schematic diagram and design, what you need to know is, what is PCB?
There are basically printed circuit boards (PCBs) in electronic equipment, also known as printed circuit boards. This green circuit board made of precious metals connects all the electrical components of the equipment and enables it to run normally. Without PCB, electronic equipment will not work. PCB schematic diagram and PCB design
PCB is a simple two-dimensional circuit design, which shows the functions and connectivity of different components. The PCB design is a three-dimensional layout, which marks the position of components after ensuring the normal operation of the circuit.
Therefore, PCB schematic diagram is the first part of designing printed circuit board. This is a graphical representation, which uses agreed symbols to describe circuit connections, whether in written form or data form. It also prompts the components to be used and how they are connected.
As the name implies, PCB schematic diagram is a plan and a blueprint. It does not explain where the components will be placed specifically. Instead, the schematic diagram lists how the PCB will eventually achieve connectivity and constitutes a key part of the planning process.
After the blueprint is completed, the next step is PCB design. It is the layout or physical representation of PCB schematic diagram, including the layout of copper traces and holes. The PCB design shows the locations of the above components and their connections with copper.
PCB design is a stage related to performance. Engineers build real components on the basis of PCB design, so that they can test whether the equipment works properly. As mentioned earlier, anyone should be able to understand PCB schematic diagram, but it is not easy to understand its function by looking at the prototype.
Both stages have been completed, and after you are satisfied with the performance of PCB, you need to implement it through the manufacturer.
PCB schematic elements
After roughly understanding the difference between the two, then let’s take a closer look at the elements of PCB schematic diagram. As we mentioned, all connections are visible, but there are some considerations to keep in mind:
In order to be able to clearly see the connections, they are not created to scale; They may be very close to each other in PCB design.
Some connections may cross each other, which is practically impossible.
Some connections may be on the opposite side of the layout, with a mark indicating that they are linked.
This PCB “blueprint” can use one page, two pages or even several pages to describe everything that needs to be included in the design.
The last thing to note is that more complex schematics can be grouped by function to improve readability. Arranging the connection in this way will not happen in the next stage, and the schematic diagram usually does not conform to the final design of the 3D model.
PCB design elements
Now it’s time to study the elements of PCB design documents more deeply. At this stage, we transition from a written blueprint to a physical representation constructed with laminate or ceramic materials. When a particularly compact space is required, some more complex applications require the use of flexible PCB.
The content of the PCB design document follows the blueprint made by the schematic diagram process, but, as mentioned before, the two are very different in appearance. We have already discussed the schematic diagram of PCB, but what differences can be observed in the design documents?
When we talk about PCB design documents, we are talking about a 3D model, which includes printed circuit boards and design documents. They can be single-layer or multi-layer, although two layers are the most common. We can observe some differences between PCB schematic diagram and PCB design documents:
All components are in the correct size and position.
If two points should not be connected, they must be bypassed or switched to another PCB layer to avoid crossing each other on the same layer.
In addition, as we briefly talked about, PCB design pays more attention to the actual performance, because this is to some extent the verification stage of the final product. At this point, the practicality of the design must come into play, and the physical requirements of the printed circuit board must be considered. Some of them include:
How does the spacing of components allow sufficient heat distribution?
Edge connector
Regarding the current and heat, how thick must the various traces be?
As physical limitations and requirements mean that PCB design documents usually look very different from the design on the schematic diagram, the design documents include screen printing layers. The screen printing layer indicates letters, numbers and symbols to help engineers assemble and use the board.
It is required that after all components are assembled on the printed circuit board, they can work as planned. If not, you need to redraw. conclusion
Although PCB schematic diagram and PCB design documents are often confused, actually making PCB schematic diagram and PCB design refer to two independent processes when creating printed circuit boards. The PCB schematic diagram that can draw the process flow must be created first, then the PCB design can be carried out, and the PCB design is an important part that determines the performance and integrity of PCB.