Drawing PCBs
An introduction to PCB
If this is the first time you hear about PCB, you are probably wondering what it is. PCB is simply the acronym for Printed Circuit Board, which is a rigid structure that contains an electrical circuitry made up of embedded metal wires known as traces, and bigger areas of metal known as planes. Why do we use this electronic circuit? A PCB is used in different devices to provide mechanical support and a pathway to its electronic components.
In simpler words, it is a board that connects electronic components together and is used in almost every computer and every electronic device today.
More than 5 year experience in Hardware and Software Systems
Integrated Circuits (ASIC & FPGA) described in VHDL & Verilog; verified and synthesized with open source tools; and printed with open standard cells.
Printed Circuits Boards drawn, printed, verified and tested with open source tools.
Drawing Printed Circuit Boards
We offer Printed Circuit Boards Schematic Diagrams drawn with open source tools such as KiCad or gEDA. KiCad and gEDA are cross platforms and open sources of Electronic Design Automation tools.
Maybe you have heard about breadboards. Well, they are fine for prototyping circuits, but a PCB is better. This is simply because breadboards are not great for actually using what you are creating because the components can get loose. So, the best way to make your project permanent is to put it on a PCB.
Today we are going to explain to you how to design a PCB layout. It is important that you optimize your design because the performance of the circuit will directly depend on how it is laid out on the PCB.
Start with a schematic
Even if it is not necessary, we highly recommend that you make a schematic of your circuit before you start designing your PCB. This way you will have a blueprint and you will be able to lay out the traces and place the components on the PCB.
There are many programs where you can start your schematic. We use KiCar and gEDA. There you will have a blank canvas where you can draw it. Some advice we give you is to put all your schematic symbols on the canvas before drawing and wires. You need to associate every symbol you use to a PCB footprint. This PCB footprint will define the component’s physical dimensions. Also, the placement of the copper pads or through holes.
The next step is to start drawing the traces. Then, we recommend you label the symbols, so the labels will be transferred to the PCB layout and, eventually later on, be printed on the final PCB.
Right after the symbols are labelled, you have to import the schematic into the PCB editor.
What to keep in mind while designing your PCB
PCB design optimization
Something you should do is divide the circuit into sections. Each section according to a function. So, before that, you have to identify what each part does.
Also, it’s better if the components in each section are grouped in the same area of the PCB. This way the conductive traces will be kept short. If you do not do this, there will be long traces. And long traces can pick up electromagnetic radiation from other sources, ending up in interferences and noise.
Another advice is to make a star configuration, which means to supply each section of the circuit with separate traces of equal length. Then, each section will get an equal supply voltage.
PCB size and shape
The usual thing is to design a PCB as small as possible, with common shapes such as round or triangular. This will depend on what you are building.
For example, if you want to put the PCB into an enclosure, the dimensions may be limited by the size of the housing. If this is your case, you will need to know the dimensions of the enclosure before you lay out the PCB. This way everything will fit.
Create the PCB layout
You are probably going to be able to do this step with the same program as before. Just open it with “convert project to PCB”. Everything should be transferred automatically.
Then you will see some ratsnest lines, which are thin blue lines connecting the components. They are virtual wires that represent the connections between components.
This is the moment when you can start arranging the components. There are some circuits that perform better with some components in specific locations, so you should do some research.
The next step is to start drawing the traces. But you can do this automatically by using the software’s auto-router, which works better if the circuit is simple.
Order the PCB
You can choose the options for your PCB order in the same program that you are using: the number of PCBs you want to order, layers, dimensions, color… Also, you can download your PCB’s files in case you want to send them to a different manufacturer.
In conclusion, we can say that making your own Printed Circuit Board is so much fun and rewarding, regardless of all the working hours.
QueenField’s services
As we said before, you can choose QueenField’s services. This company has more than five years of experience in Hardware and Software Systems.
Why should you choose QueenField? Easy! Because it has mixed implementations (digital designs implemented in VHDL and System Verilog), UVM and Formal Verification (digital designs simulated and verified using universal and formal methods) and 100% Open Hardware (open source hardware descriptions and open source tools used).
If you still have doubts, you should meet the hardware/software engineer who is behind the company: Paco Reina Campo. He is the founder and electronic engineer at QueenField since September 2004. He also has five-year experience in hardware and software systems, specialized in digital design and verification (ASIC, FPGA), with emphasis on Hardware Description Languages (Verilog, VHDL). He is focused on the design, verification, and simulation of Integrated Circuits and Printed Circuit Boards.
