PCB Design in Modern Electronics? – DSL Electronic Design

Printed Circuit Board (PCB) design is the cornerstone of modern electronics, serving as the foundation for nearly all electronic devices, from simple household gadgets to complex systems like computers and smartphones.

At its core, PCB design involves creating a layout that electrically connects and physically supports electronic components using conductive tracks, pads, and other features etched from copper sheets and laminated onto a non-conductive substrate.

This process is critical for ensuring the functionality, reliability, and manufacturability of electronic devices, and one of the cornerstones of our work here at DSL.

The Basics of PCB Design

PCB design begins with a discussion with our customers. From there, a conceptual design or schematic is devised, focusing on the logical connections between components. This is where our designers – assisting every step of the way – will determine the components required, their values, and how they should be connected.

Once the schematic is complete, the next step is to translate this logical representation into a physical layout that can be manufactured. This involves placing the components on a PCB and routing the electrical connections between them.

The goal is to optimise the layout to minimise noise, interference, and signal degradation, while also ensuring that the board can be manufactured cost-effectively.

DSL work with both basic control circuitry and multi-layer multi-board projects, and so the detail and difficulty of each stage will depend on the project. Let’s look at this process in a little more detail.

Layers in PCB Design

PCBs can have multiple layers of conductive material, typically made of copper, separated by layers of insulating material. The simplest PCBs are single-sided, with one layer of copper, while more complex designs can have multiple layers, sometimes up to 16 or more. Multi-layer PCBs allow for more complex circuits to be created in a smaller space, which is particularly important in modern electronics where miniaturisation is crucial.

The layers in a multi-layer PCB typically include:

1. Signal Layers: These are the primary layers where the electrical connections (traces) are routed.
2. Power and Ground Planes: These layers distribute power and provide a reference ground across the PCB. They help to reduce electromagnetic interference (EMI) and improve signal integrity.
3. Internal Layers: These layers may be used for additional signal routing or for more specialised functions, depending on the complexity of the design.

Design Considerations

When designing a PCB, we take multiple factors into account to ensure that the final product performs as intended. Some of these include:

1. Component Placement: The placement of components on the PCB is critical for ensuring proper functionality. Components that interact frequently or have high-speed signals between them should be placed close together to minimise signal paths and reduce the risk of interference. Additionally, thermal considerations are important, as components that generate heat need to be placed in such a way that allows for proper heat dissipation.
2. Routing: Routing is the process of connecting the components on the PCB using conductive traces. The width of these traces, their length, and the spacing between them will affect the electrical performance of the PCB. High-speed signals, for example, need to be routed carefully to avoid issues such as signal reflection or crosstalk.
3. Thermal Management: As electronic devices become more powerful, the amount of heat they generate increases. Effective thermal management is therefore needed. This can be achieved through proper component placement, the use of thermal vias (which help to dissipate heat to other layers of the PCB), and the inclusion of heat sinks or thermal pads.
4. Signal Integrity: Signal integrity refers to the quality of the electrical signals as they travel through the PCB. Poor signal integrity can lead to errors in data transmission, which can cause the device to malfunction. To maintain signal integrity, our designers consider factors such as trace impedance, the use of ground planes, and the minimisation of noise and interference.
5. Manufacturability: This includes ensuring that the PCB can be fabricated using standard manufacturing techniques, which helps to keep costs down. Of course, our designers also consider the tolerances of the manufacturing process, as well as the assembly process, including the placement of components and the soldering process.

Or, if you come to us with your design, but have some reservations, our designers and engineers are also skilled in the PCB re-design process.

PCB Design Tools

PCB design is typically carried out using specialised software tools known as Electronic Design Automation (EDA) tools. These tools allow designers to create the schematic, lay out the PCB, and simulate the circuit’s behaviour before it is manufactured. Please look here to see the tools that we at DSL use. In general, the most popular PCB design software tools include:

1. Altium Designer: Altium Designer offers a comprehensive set of features for schematic capture, PCB layout, and simulation. It is known for its user-friendly interface and powerful capabilities.
2. Eagle: Eagle is a popular PCB design tool, especially among hobbyists and small-scale designers. It offers a good balance between functionality and ease of use, and it is also available for free with certain limitations.
3. KiCad: An open-source PCB design tool, KiCad is a popular choice for those who prefer a free alternative to commercial tools. It offers a robust set of features and is widely supported by a large community of users.
4. OrCAD: OrCAD is known for its advanced simulation capabilities and is often used in high-end, complex designs.
5. CircuitMaker: Developed by Altium, CircuitMaker is a free PCB design tool aimed at hobbyists and makers. It provides many of the features of Altium Designer but is more accessible to beginners.

Printed Board Manufacturing Process

Once the PCB design is complete, the next step is manufacturing the board. The manufacturing process can involve several steps:

PCB Manufacturing

1. Printing the Design: The PCB design is first printed onto a photographic film, which is then used to create the circuit pattern on the copper layer of the PCB.
2. Etching: The copper that is not protected by the circuit pattern is etched away, leaving only the desired conductive traces.
3. Drilling: Holes are drilled into the PCB for through-hole components and vias, which connect the different layers of the PCB.
4. Plating: The drilled holes are plated with copper to create electrical connections between layers.
5. Solder Mask Application: A solder mask is applied to the PCB to protect the traces and prevent solder bridges between closely spaced components.
6. Silkscreen Printing: A silkscreen is applied to the PCB to add labels, component identifiers, and other important information.
7. Surface Finishing: A surface finish is applied to the exposed copper pads to protect them and ensure good solderability.

 PCBA Manufacturing

1. Assembly: We then solder the components onto the PCB using surface-mount technology (SMT) or through hole technology (THT). Each component is precisely placed, cementing DSL’s reputation for highly robust and reliable PCB assemblies.
2. 2. Inspection: Boards will undergo full visual inspection both manually and via a 3D AOI (Automated Optical Inspection) process to identify any manufacturing issues.
3. Testing: Boards will undergo electrical, functional, and environmental testing to ensure the highest level of integrity.

Trends in PCB Design

PCB design continues to evolve as technology advances, and we’d be happy to discuss any novel ideas that you may have. Some of the key trends shaping the future of PCB design include:

1. Miniaturisation: As devices become smaller and more powerful, the need for smaller and more complex PCBs increases. This has led to the development of advanced manufacturing techniques, such as HDI (High-Density Interconnect) PCBs, which allow for more components and connections to be packed into a smaller space. Our engineers frequently operate at a submillimetre scale.
2. Flexible PCBs: Flexible PCBs, which can be bent and folded, are becoming increasingly popular in applications where space is limited, or the PCB needs to conform to a specific shape. These are commonly used in wearable devices, medical devices, and certain automotive applications.
3. Advanced Materials: New materials, such as those with better thermal and electrical properties, are being developed to meet the demands of modern electronics. These materials help improve the performance and reliability of PCBs in demanding applications.
4. 3D PCB Design: With the rise of 3D printing and additive manufacturing, 3D PCB design is becoming more feasible. This allows for the creation of PCBs with complex shapes and structures, which can be integrated more closely with other components in a device.
5. Artificial Intelligence (AI) in PCB Design: AI is beginning to play a role in PCB design, particularly in the optimisation of layouts and the prediction of manufacturing issues. AI can help designers create more efficient designs and reduce the time it takes to bring a product to market. At DSL, we have already adopted 3D AOI testing.

PCB design is a critical aspect of modern electronics, enabling the creation of complex, high-performance devices in a compact and reliable form. As technology continues to advance, PCB design will continue to evolve, with new materials, techniques, and tools shaping the future of the industry.

Since PCB design is such an essential facet of electronics, please get in touch with us if you are looking for a cost-effective, yet high-quality and professional approach for you or your company’s next project.