Despite the fact that PCBs are the essential building blocks of the electronics sector, it is crucial to ensure that their full potential is realized. However, there are situations when a PCB may not perform as required by the circuit owing to a variety of factors. Weak solder joints, inadequate heat management, improperly placed traces on the board, etc. may have an impact on the general performance of PCBs when in use. A PCB designer must consider a number of procedures from the very beginning of the designing process in order to address these problems. The smooth transmission of data across the circuit is influenced by various elements, including the material used, the size of the holes, the spacing between the lines, etc. Designers must strive for error-free current flow throughout the designing process.
Characteristics of an Optimized PCB
PCBs must be the optimum support for circuits and a carrier for electrical connections between circuits in order to function as an essential electronic component. An optimized PCB has a variety of important features. These are what they are:
- PCB Material: Various PCB materials can be employed for a variety of operations and a wide range of needs. Some of the most popular PCB materials include FR-4, FR-1, G-10, and others because of their superior insulating capabilities and high dielectric strengths. High-quality base materials should be chosen in order to prevent problems like open circuits, delamination, acid traps, etc.
- Superior Copper Cladding Quality: A solid PCB contains copper cladding that adheres to the tolerance guidelines established by IPC4101 ClassB/L quality specifications. This allows for greater control of the dielectric thickness, which lowers the departure from the performance of the PCB’s intended value. Additionally, since copper cladding alone cannot fulfill the task, the quality of the components must also be the major priority.
- Hole Wall Width: The optimal PCB hole wall is 25 microns thick and covered in copper. This is one of the key characteristics of the PCB since it improves the board’s capacity to withstand z-axis expansion. It is important to take precautions to prevent blowing through PCB holes since this could result in connectivity problems that could develop as a result of assembly difficulties.
- PCBs without Track Cuts: The high reliability of a PCB can be attained by making sure that no repairs of any kind are made using solder and solder break lines. The PCBs perform flawlessly as a result of solder-free repair, necessitating no maintenance of any kind.
- Positional Tolerance of a PCB: A clearly defined PCB needs to have its mechanical boundaries and schematics established within acceptable operational bounds. Additionally, it must be ensured that the PCB’s electrical characteristics are established in accordance with the board’s applications. to guarantee reliable operation during the circuit’s operation.
Optimization of electronic component selection and placement
To improve the device’s signal quality and performance, the PCB must be optimized, which necessitates careful component selection and arrangement. Numerous issues that might impact production, ease of servicing, functionality, and even the lifetime of the circuit board can result from improper component placement and selection. A component’s selection and placement are crucial steps, thus choosing the wrong ones or arranging them incorrectly could have an impact on the finished result. Therefore, a designer should adhere to the suggested processes to efficiently and accurately design a PCB that is free of errors.
Choosing the components
The designing phase is the first and most important step in the manufacturing process of a PCB. To prevent problems in the finished product, the designer must be careful when choosing the components. Therefore, it is important to check that the appropriate diodes and capacitors are specified for the board; doing so will reduce the likelihood of component failure. Lack of understanding of the components and applications during PCB synthesis may cause problems with component selection. Here are a few processes for component selection for optimizing the PCB assembly, as the designer’s selection of components may have an effect on the final quality of the assembly:
- Verifying component availability: It’s crucial to confirm component availability before creating the list of necessary components. Component shortages occur as a result of supply chain disruptions, production capacity issues, or obsolescence, which can delay PCB assembly and increase the cost of the final product. Therefore, a designer must ensure that the components they choose are easily accessible.
- Recognizing the end-use scenario: The environment should be taken into account in order to ensure a high quality PCB during the assembly process because temperature and moisture levels can have a detrimental impact on a component’s functionality. The project’s needed materials and coating should be built to withstand the demands of the surrounding environment. If this phase is skipped, the end result may suffer long-term consequences.
- Using the components with equivalent replacements will help you prevent the inconvenience brought on by a lack of any one component. This backup strategy will lessen the need for redesign or requirement redefinition in the event that a component is unavailable due to a crisis.
Component Placement
Electronic component placement optimization is the process of arranging components so that all essential functions, manufacturing, assembly, service, maintenance, and cost factors are satisfied. The designer should exercise greater caution when working with the parts since some parts of the gadget may be more vulnerable to harm than others. When positioning the components, problems with noise coupling and heat dissipation can occur. When the analog and digital high-speed components are not separated, noise may be generated. There will be a disruption in the PCB’s operation if these problems are disregarded. Therefore, the assembly process should be given top priority because problems could occur if some fundamental procedures are not followed during component placement. If the IC alignment is not carried out in accordance with the orientation, the PCB assembler will display various faults. These are some factors that should be taken into account during the component placement process to guarantee that the PCB design is successful before the design is finalized.
Module compartmentalization
The designer should isolate the analog, digital, power, and audio components when working on a complex system. The components ought to be organized into groups and kept to a single region of the PCB. As a result, the noise caused by cross-coupling between the parts will be reduced.
To prevent crosstalk and signal deterioration, analog and digital grounds must to be maintained apart.
Fig 1 : Module compartmentalization
Source – https://resources.altium.com/sites/default/files/inline-images/migrate/jxUbt95Ot-u625dH_oBl1Uvz1Gs4pue9CHbYOFW_JxO8qCWcT8EV7MeS_wUqWPAkHHfJRIBqqwDU0qJBbxH64ahuFAVPVt8XCJiia-3v7y8CqAH1UgLtdyyLhDfI5_huESxMvOXr
Placement of connectors at the edge
The designer should keep them at the border of the PCB while working on a PCB that employs wire-to-board connectors that need the user to physically enter the cable. This will lessen the possibility of harming nearby components and make the connecting process simpler.
Fig 2: Placement of connectors
Source- https://www.google.com/url?sa=i&url=https%3A%2F%2Felectronics.stackexchange.com%2Fquestions%2F353426%2Fconnector-placement&psig=AOvVaw2Cf2z0QZiDB4kZb_2eXpoD&ust=1650775817158000&source=images&cd=vfe&ved=0CAwQjRxqFwoTCLii3bGxqfcCFQAAAAAdAAAAABAD
Avoid overcrowding the PCB
There are specific physical requirements to meet throughout the PCB designing process, which prevents packing components onto the PCB where there is practically any room corresponding to their sizes. Overcrowding or clustering the active elements and componentry too closely together can potentially cause overheating. Components can burn if they are overheated, which eventually results in PCB failure. Therefore, the designer should think about allowing some space between the components to prevent overcrowding.
Fig 3: PCB overcrowding
Source- https://aws1.discourse-cdn.com/wd/optimized/2X/d/d88ed6f2a27d3f4f9609b35ca698dbc816f2ca67_2_1024x762.jpg
Ensuring component’s edge clearance
Because it is advisable to keep small and delicate components away from the edge of the PCB, the PCB must be constructed with a dummy strip for support. The dummy strip will come off after all the parts are put together, which could harm any SMD components that were placed around the edge.
Fig 4: Edge clearance
Source- https://www.tempoautomation.com/wp-content/uploads/2019/04/shutterstock_77648.jpg
PCB optimization procedures
Creating the Blueprint – The PCB’s blueprint is nothing more than the conceptual layout of the circuit board illustrated on paper as the initial stage in developing a PCB. A designer can create the plan using a variety of websites and software. A schematic is the name given to the software’s digital rendition of the blueprint. More specifically, the schematic is just a plan that combines all the parts, connectors, connections, and power sources needed for the circuit. Additionally, the manufacturer can use these circuit schematics to construct the PCBs.
- Using PCB Design Software: Following the completion of the blueprint, it is crucial to simulate the PCB and the circuit using any available simulating software. This allows the designers to get insightful feedback on the created circuits. There are several PCB simulation programs, such as Altium, Eagle, etc., that are useful since they have a library of components with more than 500,000 pieces, such as connectors, cables, power sources, etc.
- Routing: Routing simply denotes how electricity travels from the circuit board to each component. Additionally, the copper traces on a PCB that follow the circuit board show the direction of the electricity flow between the parts. Maintaining clear, concise, and direct channels is crucial while building relationships. These copper traces must be wide enough to withstand the circuit’s high temperature.
- Layers – Using many layers was not possible with traditional PCB manufacturing technologies. However, the development of technology has made it possible for PCBs to have numerous layers. The performance of PCBs overall has greatly increased due to the possibility of adding more components and the tendency for stronger connection provided by additional layers. A PCB also has additional layers to minimize overpopulation.
- Making a Prototype: It’s usually a good idea to make a PCB board prototype before going into mass manufacturing. Once the performance of the prototype is assessed, there is a very good chance that changes will be made to the PCB design. It is always possible to return to the schematics after testing a prototype to make adjustments and better optimize the design and layout of a PCB.
- Mass manufacturing: After confirming that the PCB prototype is free from errors or flaws, mass production of the PCB can begin. Maximum accuracy can be achieved by using machine-driven tools and computer guidance. This aids in avoiding future operational disasters by preventing short circuits and incomplete circuits.
Fig. 5: Mass manufacturing Mass-produced printed circuit boards are available at https://cdn.thomasnet.com/insights-images/embedded-images/080b5fea-ad81-4698-8842-683245aae365/f326124c-b1f3-4416-9e45-16704a843f35/FullHD.jpg.
Conclusion
The selection of components and their location on PCBs are crucial for achieving high PCB reliability. When choosing components, it is crucial to consider their availability as well as their intended purpose in order to keep track of their specs and parameters. To prevent problems with signal integrity, components should be arranged so that analog and digital elements are kept apart from power components. It is important to keep connector placement at the edge, as this lowers the possibility of harming neighboring components and makes connecting output ports easier. Every opportunity should be taken to avoid overcrowding, and the design should be such that delicate components are maintained closer to the center of the PCB. The optimum initial step to visualizing the output of each component and element of the circuit is to create a design or schematic. For a better understanding of the circuit and to correct numerous faults throughout the analysis of the PCB design flow, simulation tools and software are crucial. To prevent current wastage, routing traces on the PCB must be kept short, direct, and have distinct channels linking the various components. Layering makes it feasible to have more space between components on PCBs, which helps to solve the problem of heat sinks. Designers must always have at least one prototype created before going into mass production, both for potential future revisions and for further optimization.
