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Printed circuit boards (PCB) are the brain of almost all electronic and mechanical devices. As the center of command, PCBs are the most important part in electronic circuits and equipment. Without a sound and well-founded PCB design or PCB layout, any PCB and the device it powers is most certainly bound to fall flat.
This is what this article is all about–to teach you all the PCB design basics so you can avoid the dreadful cost of missing the mark. In the following chapters, you will learn all the things you need to learn in the world of PCB design or PCB layout process, including:
But before we dive into the PCB design process, let us first get to know a couple of common PCB layout terminologies that you will bump into later on.
A printed circuit board, sometimes called a printed wiring board, is a waferboard defining the mechanical and electrical wire structure of the circuit.
Gerber files are the CAD file generated from a PCB design software like Eagle and Altium that a PCB manufacturer can refer with to build the PCB layer structure. The most commonly support Gerber file format is RS-274X.
Schematic capture or entry is the step in the PCB design cycle where the electronic diagram or schematic of the designed electronic circuit is made using a schematic capture tool or a schematic editor. Normally, a manual hand sketch of the circuit design precedes schematic capture.
A schematic capture tool allows you to design a document that represents electronic component symbols and the interconnections between them in a graphical way. Before a PCB is generated, the symbols are mapped to component footprints, while the symbol interconnections are converted into a netlist that details the connections between the component footprints in the layout process.
Once an electronic circuit is designed, circuit simulation is done to analyze and test the initial design. Most schematic capture tools allow you to perform interactive circuit simulation with the same schematic circuit representation used for layout, which is rather convenient.
A numerically controlled (NC) file specifies the size and position of holes used for unplated holes, plated through-holes, and holes for vias.
As previously stated, PCB designing is an extremely important process and it could be the most critical part of an electronics engineer’s job. To create a PCB layout design, you need a tried-and-tested PCB design software to help you lay out the electrical circuits.
A PCB design software generates the mechanical and wiring connection structure of the PCB from the netlist. A PCB design software lets you place the wiring connection structure on multi-layers, and then generate computer-aided design (CAD) files, which is needed to manufacture a PCB.
If you do not know how to design PCBs and are not willing to get your hands dirty, you can always find PCB manufacturing companies that have PCB design services or PCB layout services. We will talk more about the PCB design process in Chapter #5.
Not all PCB design software is created equal, so selecting the right PCB design software matters. Before you choose a PCB design software, there are several factors to deliberate on and ask the following questions?
To know more about PCB design software, here are some of the most popular ones used by industry leaders today. Here we will tackle the key features of these PCB design software, how much these PCB design software cost, and how these PCB design software can help you with your PCB layout design.
EAGLE, short for Easily Applicable Graphical Layout Editor, is the most popular PCB design software originally developed by CADSoft Computer and is now owned by Autodesk. Apart from being free, EAGLE’s popularity among hobbyists and professionals alike can be attributed largely to its simple and easy-to-use interface on top of its massive library of electrical and electronics components.
EAGLE has a schematic editor and a PCB layout editor. The schematic editor is used to add all components and connect them based on circuit requirements. Features of EAGLE’s schematic file includes an electronic rule checking, modular design block, real-time design synchronization, and multi-sheet schematic.
Schematic is automatically converted in the PCB layout editor so you can set components according to complexities. The features of EAGLE’s PCB layout editor include a PCB routing engine, obstacle avoidance, and alignment tools. EAGLE can also generate Gerber files.
EAGLE is available to download on Windows, Linux, and Mac.
Altium Designer does not only cost an arm and a leg, but it is also the most expensive PCB design software on the market today. A one-year subscription to this PCB design software costs $7,245.
Although it is too costly of a PCB design software for smaller companies and freelancers, Altium Designer is a good investment as it gives you all the most advanced features you will need in a PCB layout tool. Altium Designer features include PCB designing, field-programmable gate array (FPGA) development, and schematic capture.
Of course, it also comes with common features like offline design system, auto cross-probing, collision detection, interconnected multi-channel design, visual layer stack management, fast and top-notch PCB routing, signal integrity, and hole tolerance definitions.
Altium Designer uses a different graphics processing power that cannot be found in inexpensive PCB design software. No matter how complex your PCB layout is, Altium Designer can do the magic for you and produce PCB design results fast. Once you are done, you can have a 3D preview of your PCB design, allowing you to see even the minutest details of the components.
Altium Designer is available to download on Windows.
OrCAD is another premium PCB design software that offers both PCB design and circuit simulation solutions.
OrCAD Capture is intended to design PCB layouts. Under the PCB design suite are OrCAD Standard, OrCAD Professional, and Allegro PCB.
OrCAD Standard is for a concept to the production design environment and costs $1,300 annually. OrCAD Professional offers professional grade PCB design capabilities, which costs $2,300. Allegro PCB is perfect for experts level PCB design.
OrCAD PSpice (Personal Simulation Program with Integrated Circuit Emphasis) is used for circuit simulation and testing. OrCAD PSpice can also simulate PCB design from MATLAB/Simulink, which makes it different from the other PCB design software here.
PSpice Designer is for industry standard simulation technology that has 33,000 parts in its library. It costs $1,980 for a start.
PSpice Designer Plus is used to analyze PCB design for reliability, cost, and yield. It has all the features of the basic PSpice Designer and other features like design optimization, reliability analysis, cost analysis, HW/SW co-simulation, yield analysis, and system C/C++ modeling and simulation.
OrCAD is available to download on Windows, MacOS, and Linux.
KiCAD is a free PCB design software for electrical design automation. Since it does not require a license, its documentation is shared with Creative Common Attributes GNU General Public License.
Even as a free PCB design software, KiCAD can give your premium PCB design software a run for your money. It can be used to create a bill of materials (BOM) and supports Gerber files and 3D PCB layout. Also, KiCAD has its own library where you can find most electrical components.
KiCAD has five parts: a project manager; PCBnew to preview PCB layout in 2D and 3D; eeschema as a schematic capture editor; gerbfile to generate Gerber files; bitmap2component to convert images to a footprint.
KiCAD’s schematic capture editor and PCB layout viewer are the most used features of this PCB design software. Eeschema supports electrical rule checking, custom symbol creation, and hierarchical schematic sheets. Pcbnew provides a convenient way to do PCB routing and troubleshooting.
So if you want to modify your PCB design’s vias, holes, traces, or any other components of your PCB layout design, KiCAD makes it simple for you. Both KiCAD’s schematic capture editor and PCB layout viewer support EAGLE files.
KiCAD is available to download on Windows, MacOS, Linux, and Ubuntu.
EasyEDA is a web-based electronic design automation (EDA) tool, which makes it a great option if you are looking to free up space on your device. You only need to go to https://easyeda.com and access it from there. EasyEDA is known for its easy to use interface, so if you are totally new to the world of PCB layout design, it can never be a bad choice at all.
One of the benefits for using EasyEDA is the massive amount of open source projects that you can refer to. How massive? EasyEDA now has over 700,00 projects in its library with symbol and footprint of components. If you are looking for a component that is available, you can always create your own.
Another advantage of this PCB design software is its support for other PCB design software libraries and schematic, including EAGLE, Altium, LTspice, and DXF.
As a PCB design software that was originally developed for teaching electronics programs in colleges, Multisim became the commonly used PCB design software among researchers and students because of its research, teaching, and circuit design solutions rolled into one.
Its ability to analyze analog, digital and power electronics make Multisim’s simulation technology robust. Some of its distinct functionalities include integration with new embedded targets, improved parameter analysis, and simplified design with user-definable templates.
Multisim is as powerful as EAGLE. But if you are going to compare their strengths, you would see a stark contrast between the two PCB design software. Multisim has a great simulation environment that you cannot find in EAGLE. For PCB layout designing purpose, EAGLE is a better platform than Multisim.
Multisim is available to download on Windows.
PCB design or PCB layout needs a brilliant fusion of different technical capabilities. It is an indispensable link between manufacturing and engineering, thus, dictates the overall functional performance of a final product.
It is this exact same reason why it is always a better idea to seek the aid of experienced and skilled PCB manufacturing companies that know how to design PCB layout or offer PCB design services or PCB layout services for top-notch PCB designs or PCB layouts. They know all the PCB basics, PCB steps, PCB rules, and PCB guidelines that you probably are not interested in knowing for the first time.
Working with a company that knows how to design PCB layout or offer PCB design services or PCB layout services can help you build the ideal PCB for your product. If ever you are on the fence whether or not seeking PCB design services or PCB layout services is more beneficial to you, it is important to grasp its advantages. Let us discuss to you the benefits of PCB design services or PCB layout services in the manufacturing industry.
Designing PCB layouts can bear a great advantage if you have access to a third-party source of technical competency. With PCB design services and PCB layout services, you can guarantee that your PCB layouts and components pass the requirements. So whether you need advice on concept ideas, schematics, or prototypes, PCB design services and PCB layout services have them readily available for you to access.
When looking for PCB design services and PCB layout services, it is important to know if they have worked on a range of projects before and their techniques and technologies. Their experience can help you in making the right trade-offs in choosing strategies or technologies to allow best time-to-market. This sort of competence can dictate the success of your PCB design in some way.
PCB design services and PCB layout services have a streamlined process from PCB layout design down to verification. Using PCB design services and PCB layout services enables them to evaluate your plans and check any factors that can be improved on your future products because they know how to design PCB in the first place.
Additionally, PCB design services and PCB layout services can help you determine parts that could be reduced to save money. PCB design services and PCB layout services can review you schematics and existing boards to check how the product can be improved to simplify the design.
At the core of every successful electronic product is the PCB design. A company that offers PCB design services and PCB layout services with experience from product specification down to production can help you transform your PCB design into a force.
In terms of reworks, PCB design services and PCB layout services normally label components on the board. Each component is conveniently placed in a predetermined location based on their function. This makes the process of detecting problems and repairing issues fairly manageable.
Companies with PCB design services and PCB layout services follow strict ISO guidelines and standards to make sure that they deliver only the highest quality results. And the more experienced they are, the more you can depend on the quality they can provide,
Design flaws are inevitable; even the most experienced PCB design services and PCB layout services cannot get away with them at times. But PCB design services and PCB layout services are also good at finding flaws in your PCB layout designs. PCB design services and PCB layout services can contribute additional knowledge to resolve any issues with PCB layout designs, and they can give you a new perspective on issues which may help you resolve products as quick as possible.
Enhanced quality could mean a lot of things in the PCB layout design, including reduced PCB layout design flaws, low electrical noise, low material waste, and high production yield, among many other things.
PCB prototypes are important to the final development of PCBs. So it really pays to produce prototypes in a timely manner to stay on schedule. Working with PCB design services and PCB layout services can accelerate your time-to-market by using their expert development engineers and designers. It also reduces risk and lowers development cost without sacrificing quality.
Many big PCB design services and PCB layout services have multiple delivery centers spread across the globe, and this helps them accomplish PCB design and PCB layout orders quickly. If you are looking at PCB design services and PCB layout services in China, it is important that the company has satellite offices in the United States or anywhere near you.
PCB design services and PCB layout services tend to be more cost-effective. Depending on some factors, you might be able to save a lot of money from hiring external PCB layout designs. There are a lot of companies out there who can provide top-class PCB design services and PCB layout services at a cheap cost. Others even offer customized pricing and discounts.
No matter what electronic products, the PCB layout design is one of the most essential design elements. In most cases, an electronics hardware design engineer will design the circuit, and a PCB layout expert takes care of the PCB layout and PCB design from schematic made using a PCB design software.
Not only a PCB layout designer’s proficiency in PCB design software is necessary but also a combination of standards and techniques used to make sure that the basic circuit design is successfully transferred to an overall print PCB that can be produced in an electronic circuit manufacturing environment.
Even if you do not know how to design PCB, a PCB layout design can be satisfactorily done with the help of PCB guidelines and PCB tutorials. Although, we must stress out that experience has no substitute.
If you are looking for PCB tips and PCB guidelines, this section covers the PCB basics and PCB guidelines you need for your PCB layout design.
Normally, reference holes and points are necessary on the board because they are used for pick and place machines and text fixtures. It is even more important to make sure that these reference holes and points are suitable for the PCB manufacturing process.
These reference holes and points sometimes intended for fixtures, other times for optical sensors. So they have to be clear of components, and not hidden or uncertain.
Determining the number of track layers of your board is a no-brainer. It is important that you have an idea of how many layers your board will have before starting the PCB layout design process.
More layers mean higher production cost. Note that you cannot decide to have a single-layer only just so you can reduce costs. The complexities of your PCB layout design will dictate how many layers are needed to accommodate all the tracks.
More often than not, board dimensions are defined by the product size. However, even before the PCB layout design starts, you should be able to estimate the size of the board and make sure that there is enough room for the components and their tracks.
It is important that at the beginning of the PCB layout design process you already know how the PCB will be mounted. Different ways of mounting may need different parts of the board to be kept vacated.
It is an industry standard to make use of a complete layer or plane for earth or power rails. Which effective way to use these must be considered at the beginning of the PCB layout design.
As we have just stated, complete planes are commonly used for earth and some major power rails. But this has a downside when it comes to noise and current capability.
Huge gaps in power planes or earth planes is not a wise move, so does having partial planes in a particular area on the board. This may cause major stress on the board which could lead to warping during the manufacturing of the bare board or later when the board goes through a hot PCB soldering process. Warping after surface mount components have been added can cause component fractures which can lead to functional defects.
Make sure to even out the standard track size that you are going to use within the PCB layout design. Narrow tracks and too close to one another increases the chances of short circuits. Also, wider tracks and too distant from one another restricts the number of tracks in a certain area; this could mean you will need more planes in the boards so that you PCB layout design can be routed.
The thin tracks used in most PCBs today only transmit a limited current. It is important to consider the track size for any that bear power rails rather than low-level signals.
Early in the PCB layout design, it is necessary to determine the pad and hole dimensions of the board. Normally, a ratio of about 1.8:1 (pad:hole) is used, although there are times a pad 0.5 mm bigger than the hole is used as the measure. This is just right for hole drilling tolerances. As the pads and holes get smaller in size, the ratio becomes more critical, especially for via holes.
Although component libraries associated with PCB design software and PCB CAD systems have libraries for the PCB and schematic footprints for different components, these may still differ during the manufacturing process. Normally, they have to be big for wave PCB soldering than for infrared reflow PCB soldering.
Therefore, the manufacturing process has to be determined first before the PCB layout design begins. This allows you to choose the best pad sizes and use them on the PCB design software and on the PCB itself.
It is important to avoid running tracks in parallel no matter the length to reduce the chances of crosstalk with signals on one track appearing on another. As you may know, crosstalk causes a lot of circuit issues most of the time, and it can be really hard to resolve once the PCB design is built.
In the case of two signal lines need to cross, it is important to have them cross at the right angles to reduce the level of mutual inductance and capacitance between these lines.
A PCB design is typically done by converting your circuit’s schematic diagram into a PCB design layout using a PCB design software. You can choose any PCB design software according to your needs and requirement. To get you started, we have listed some of the most common PCB design software in Chapter #2.
If PCB designing is something you are proficient at or you do not know how to design PCB, you can always seek the help of PCB fabrication houses that have PCB design services and PCB layout services. If you are interested to learn more about the benefits of getting PCB design services and PCB layout services, we have broken down some of its advantages in Chapter #3.
In case you want to take matters into your own hands and learn how to design PCB layout from the ground up, we will let you in on the PCB design steps. To understand the PCB design basics, PCB design rules, and PCB design steps, in this chapter we will walk you through the PCB design process and present to you some PCB design tips that you can use.
The PCB layout editor is where the magic happens. It is where the board dimensions come together and components are arranged and connected by copper traces. The PCB layout editor optimizes the conceptual schematic you have made in the schematic editor and makes the PCB routing and board dimensions more precise.
In this PCB design tutorial, we will cover the PCB design steps using the EAGLE PCB design software, from placing parts to PCB routing to generating Gerber files. We will also tackle the PCB design basics of EAGLE’s PCB layout editor.
Starting off the PCB layout design process with a schematic circuit diagram using a PCB design software like EAGLE, Altium, and others. PCB design software has a library of components that can be used to make the circuit. You can derive your circuit design’s position and tweak it according to requirement.
For the sake of this tutorial, let us use the EAGLE PCB design software for the schematic design. The schematic design is the foundation of these PCB design steps, and it is a two-part process–adding parts to the schematic sheet and wiring those parts together.
Step 1: Create a new project. Launch EAGLE to make a new project folder for the schematic design. Under the ‘Projects’ tree, there is a default ‘eagle’ folder. Right-click on it, then select ‘New Project’. Give it a descriptive project name.
Step 2: Create a schematic. To begin the PCB design process, create a schematic and add it to a project folder, then right-click on the folder and select ‘New’, and then ‘Schematic’. A new blank window should pop up.
Step 3: Add parts to the schematic. Use the ADD tool, which can be found under the ‘Edit’ menu, to place all components (frame, power input, microprocessor and supporting circuitry, connectors, etc.) on the schematic.
Step 4: Wire up the schematic. After adding every single part to the schematic, wiring them together comes next using a NET tool, which can be found under the ‘Draw’ menu.
If you want to learn more about how to design a schematic diagram, you can refer to the following tutorials according to the companies of PCB design software.
If you already have a schematic, you can open it on EAGLE and switch from the schematic editor to the related board by clicking ‘Generate/Switch to Board’ on the ‘File’ menu. This will launch a new board editor window where the parts you added from the schematic are present, stacked on top of each other and ready to be placed and routed.
When arranging the schematic board, you need to create a new PCB design based on your schematic in the schematic editor. To do this, ‘Generate/Switch to Board’ on the ‘File’ menu.
The new board file will show everything you have on the schematic–the airwires, light-gray outline of a board dimension, etc. Your goal here is to place the parts in the right places and then reduce the area of your PCB dimension outline.
Use the MOVE tool to move parts within the dimension box. Fix the dimension outline afterward. Use the DELETE tool to remove dimension lines. Then, use the WIRE tool to draw a new outline.
PCB routing is where the fun begins. Here you need to assign the gold airwires into the top or bottom copper traces and make sure to avoid overlapping two different signals. Use the ROUTE tool to draw all copper traces.
Copper traces will fail to function correctly if two signals overlap. If it is unavoidable, make sure that they cross on opposite sides of the board. Also, make sure that there is enough space between two different signal traces.
To make your life easier, you can use EAGLE’s autorouter to do it for you. However, you still need to check if it is doing the right thing. If not, you can simply click the undo button.
Checking your PCB design for errors is imperative before sending it to a Printed Circuit Board manufacturer. First and foremost, you need to check if you have routed all nets in your schematic. PCB design rules check comes after routing.
Depending on which PCB design rules check standard you want to use, most common errors usually found when doing PCB design rules checking involves too close traces, intersecting dimension lines, and overlapping signal traces.
Before finally generating Gerber files, you might have to do some finishing touches, including copper pours and silkscreen.
Adding copper pours is typically for the ground signal, and it makes your PCB layout design more professional. Adding silkscreen is also an important part of the PCB design. It makes your PCB layout design look good.
Before sending your PCB design to a PCB fabrication house, of course, you need the Gerber files. If you are satisfied with your final PCB layout design, you can generate the Gerber files of your PCB layout design.
Remember, Gerber format is like the universal language used in all PCB design software. Fabrication houses may not have support for all PCB design software formats, so Gerber files enable them to read your PCB design.
While building an electronic circuit with breadboards and zero boards is possible, it is not as efficient as with PCB since breadboards and zero boards are prone to break and are too delicate to handle a complex process of placing the components of the circuit.
Ever since PCBs that support electronic components and wiring via surface-mounted copper tracks were introduced, designing a complex electronic circuit has become more manageable. PCBs are made up of materials such as fiber and glass so they do not conduct electricity. The circuits on the board are made with copper tracks for the conduction of electricity between electronic components.
The electronic components have their allotted positions by drilling holes on the board, placing the components and then PCB soldering them in their respective locations so that the copper traces and components together create a circuit.
There are different how to design PCB layout designs. Depending on the PCB design services and PCB layout services, your PCB layout design can be manufactured in bulk using PCB fabrication machines, including drilling, plating, punching, and final fabrication methods. CNC machines, strip etching machines, optical inspection equipment, automatic plating machines, and flying probe testers can greatly help in the production of high-quality, high-yield PCBs.
As soon as you have generated the film from the finalized circuit board diagram of the PCB design software, you can send it to your manufacturer to print out the negative image or mask on a plastic sheet.
The most common types of PCB materials used today are the fiberglass epoxy (FR-4) and phenolic paper (FR-2). Most PCBs are made with an unbreakable glass or fiberglass with copper foil covering either one or two sides of the board.
PCBs made from phenolic paper with copper foil are cheaper and are often used in household electrical devices. However, it is more toxic and more prone to damage. Glass epoxy, on the other hand, is the most common but is not ideal for high-speed or RF boards.
The drilled pattern is stored in the computer, including the number of holes per panel, drill bit sizes, drilled time per load, and drilled stack, among others. The PCBs are placed into the CNC machine for hole drilling based on the pattern.
There are a couple of ways to print the PCB layout design’s circuit on the PCB, such as pen plotters and printers, dry transfers, and manual pen. But a laser printer is a better option.
To print your PCB layout design’s circuit on the PCB, take a clean copper paper and put it on the laser printer. Then, save the designed layout film on the computer. Finally, print the PCB layout design circuit on a copper paper.
The stripping and etching process entails removing the unwired copper on the PCBs. This can be done using different chemicals like ammonium persulfate and ferric chloride.
To make the solution, mix 1% of sodium hydroxide and 10 grams of sodium hydroxide pellets to 1 liter of water. Mix it up until everything is dissolved. Then, place the PCB on a chemical bowl and cleaned it up with the solution with a brush.
After finishing the PCB manufacturing process, you need to subject the PCB design and board to testing and checking for functional issues. For high-volume testing of PCBs, you can use any types of automatic testing equipment which are now available today.
PCB design or PCB layout can be a stressful part of the whole electronics manufacturing process. PCBs bring products to life, so the PCB layout design process is a very critical stage. In fact, it often dictates how the standard PCB and the product that it is going to power will perform.
If PCB layout design is not your thing or you have no time to learn all the PCB basics, PCB rules, and how to design PCB or learning how to navigate PCB design software is too much to handle, you can always turn to PCB fabricators that offer PCB design services or PCB layout services. Not only will PCB design services or PCB layout services do the PCB layout design for you, but they might also give you a peek on how to design PCB so you somehow get the idea how the process is done.
Of course, there are PCB guidelines that have to be followed when designing a PCB layout. All of these things can be rightly done and followed by PCB design services or PCB layout services without stressing out. Even so, it is important to get yourself acquainted with the whole PCB design process in one way or another because, as previously mentioned, it is a critical stage.
That is all for PCB design! We hope you have learned a ton of things from this article, from the benefits of getting PCB design services or PCB layout services to how to design PCB. If you still got questions, leave them in the comments so we can get back to you soon.
