PCB, also known as Printed Circuit Boards, is a common name in the world of electronics. PCB works as a surface which aims to provide support and proper wiring to the components and conducting materials to the electronics. It joins various points together with the aid of pads and lines. The conducting materials used in the making of PCBs are copper, heat sinks, pads and so on. Other than this, it contains an insulating material wrapped between the conductors. Printed Circuits Boards play a key role in providing power and signals to the devices. A printed circuit board must have a well-designed layout in order to increase its reliability and effectiveness. The importance of designing it is as important as component selection, and is worth time-consuming. If your layout isn?t effective enough, it can cause issues such as weak functioning of the components, faulty board and electromagnetic interference. If a person isn?t able to design the layout correctly in the first time, it can result in increased costs. To get rid of all these issues, one has to follow a set of rules and steps to design your layout.
Composition Of PCB:
A PCB isn?t a simple as it looks. Its complexity lies within the layers of materials it is composed of. The lower most layer is composed of substrate. It is usually a fiberglass, which is usually FR4. It provides toughness and thickness to it. The next material to be used is a thin sheet of copper, which is usually applied to both sides of the fiberglass. It sticks to the board with the help of heat. The copper layers can range from one to sixteen layers. The copper foil is usually thin, still its thickness may vary in different PCBs.The soldermask aims to protect the copper foil from other metals or solder, hence providing insulation to it. The silkscreen layer, which is usually white in colour, is supposed to be the top most layer of the Printed Circuit Board layout. On this layer, we can find symbols, letters and numbers so that it is readable and understandable by the humans. Silkscreen is used as an indicator to tell what each LED or pin is to be used for.
Steps To Design A PCB Layout:
After knowing that PCB is required, one should start working on the concept of the layout. He should be able to recognize what tasks is PCB supposed to perform. Also, there should be an idea about the features, how to locate it in the product, the sizes and lengths of the board and so on. Other than this, one should have an idea about the range of temperatures on which the PCB can work best. The other step involves developing your schematic. This contains all the required details of the rating, value and name of the components. You also need to maintain the bill of materials where you will be enlisting all the components needed for the PCB. The next step involves having a board level block diagram. This gives you an idea of dimensions of the PCB. You need to identify different regions of the components which are needed to be connected electrically. Another step involves placing the components in the PCB. It is a task which requires a lot of time to be fulfilled, as placing components is not often finalised in the first take. First-Pass Routing is yet another step to be followed. As the name suggests, one should know the possible routing of the circuit. The next which is required to be done is testing. Tests are done to make sure design is completed. If it does not match your requirements, some amendments are supposed to be done in the back stages.
Design Considerations For A PCB Layout:
There is a whole lot of things to be considered while designing a PCB. One of them is linked with the structure of the board, its shape and size. The PCBs are mostly are rectangular in shape. It should be considered that they aren?t shaped irregularly and must have enough space to accommodate all the desired components. One should also consider the number of layers they require. Adding more layers can make it more costly as per the production point of view, but the tracks are too raised through it. Other main consideration is regarding the manufacturing process. One needs to make use of reference holes which are supposed to be free of components on the board. When you are designing the layout of your PCB, you should know which components and materials are to be placed on the board. Some items aren?t available in the market or are too expensive to come across.Once who have all items in hand, you can startworking on the PCB. One should be aware of the order of components to be placed. There is known placement which works for most of the PCBs. The first in line are the connectors. Next comes the series of circuits including power circuits, precision circuits and critical circuits. The rest of the components are to be placed after this. Another consideration to make is placing the similar components in same direction. Thisenhances the process of soldering. Proper organization of the components is yet another important consideration to make. The costs are reduced and efficiency is increased. Other than this, the ground and power planes are to be kept inside of your board symmetrically. You should also know your track design and that it must be concise. Obtaining the correct ratio for size of pad to hole is also important. Other than this, it is prior to eliminate electrical issues from the PCB. One should also avoid thermal issues by letting heat dissipate. Plus, the process of testing should be continued from manufacturing till designing. This helps you fix your problems easily.
Hence, Printed Circuit Boards are supposed to be made with deep consideration and must be carefully checked at every stage. It is important to make sure you are placing the right components in the right order and time, to minimise errors.