Introduction

The world of electronics is filled with various components and technologies that work together to create functional devices. Among these components, printed circuit boards (PCBs) and printed circuit board assemblies (PCBAs) play a crucial role in the design and operation of electronic devices. 

Understanding the differences between PCBs and PCBAs is essential for engineers, designers, and manufacturers, as it helps them make informed decisions when developing new products or improving existing ones. 

This article will delve into the definitions, functions, types, and manufacturing processes of both PCBs and PCBAs, as well as explore their key differences and applications. By gaining a deeper understanding of these essential components, professionals in the electronics industry can make better choices and optimize their projects for success.

PCB: Printed Circuit Board

Definition and Function

A printed circuit board (PCB) is a thin board made of insulating material, such as fiberglass or epoxy resin, with conductive pathways etched or printed onto its surface. These pathways, also known as traces, are typically made of copper and serve as the electrical connections between various electronic components, such as resistors, capacitors, and integrated circuits. The primary function of a PCB is to provide a stable and organized platform for mounting and interconnecting these components of the circuitry, enabling them to work together to perform specific tasks within an electronic device.

Fig. 1: Bulk manufacturing of a PCB board

PCBs are designed to minimize the complexity of wiring and improve the reliability of electronic devices. By using a PCB, designers can create compact and efficient circuits that are less prone to errors and easier to troubleshoot. Additionally, PCBs provide mechanical support for the components, ensuring that they remain securely attached and properly aligned during operation. This is particularly important in high-vibration environments or when the device is subjected to physical stress.

The performance of a PCB is influenced by various factors, such as the thickness and type of the insulating material, the width and spacing of the traces, and the quality of the solder joints. These factors can affect the electrical characteristics of the board, including its resistance, capacitance, and inductance, which in turn can impact the overall performance of the electronic device. Therefore, careful consideration of these factors during the design and electronic manufacturing process is essential to ensure the optimal functioning of the PCB and the device it supports.

Types of PCBs

There are several types of PCBs, each with its unique characteristics and applications. The primary types of PCBs include single-sided (single-layer PCB), double-sided (double-layer PCB), and multilayer boards.

Single-sided PCBs are the simplest and most common type of PCB. They consist of a single layer of insulating material with conductive traces on one side. Components are typically mounted on the same side as the traces, and connections are made using through-hole soldering or surface-mount technology. Another term for through-hole technology is thru-hole, a traditional method of component mounting. Single-sided PCBs are cost-effective and suitable for low-density and low-complexity circuits, such as those found in basic consumer electronics and simple control systems.

Fig. 2: Assembling a PCB with components

Double-sided PCBs have conductive traces on both sides of the insulating material, allowing for more complex and denser circuit designs. Components can be mounted on either side of the board, and electrical connections between the two sides are made using plated-through holes (PTHs) or vias. Double-sided PCBs offer greater design flexibility and are used in a wide range of applications, including automotive electronics, industrial controls, and communication devices. However, they are more expensive to produce than single-sided PCBs due to the additional manufacturing steps required for creating the PTHs and vias.

Further reading: What is a Via: A Comprehensive Guide

Multilayer PCBs consist of multiple layers of insulating material and conductive traces, which are laminated together to form a single board. The layers are interconnected using PTHs or blind and buried vias, allowing for even more complex and high-density circuit designs. Multilayer PCBs can range anywhere from four layers to over 30 layers, depending on the manufacturer's capabilities and the application's requirements, with each additional layer increasing the board's complexity, cost, and manufacturing time. These boards are commonly used in high-performance electronics, such as computers, smartphones, and advanced medical equipment, where space constraints and signal integrity are critical considerations.

Each type of PCB has its advantages and disadvantages, and the choice of which to use depends on factors such as the complexity of the circuit, the available space within the device, the required performance characteristics, and the project's budget. By understanding the differences between these types of PCBs, designers and engineers can make informed decisions that best meet the needs of their specific applications.

PCB Manufacturing Process

The manufacturing process of a PCB involves several steps, each of which plays a crucial role in ensuring the board's functionality, reliability, and performance. The main stages of the PCB manufacturing process include design, fabrication, and assembly.

Design: The first step in the PCB manufacturing process is creating a detailed design of the board using computer-aided design (CAD) software. This design includes the layout of the components, the routing of the conductive traces, and the placement of vias and PTHs. The design process also involves determining the appropriate materials, layer stack-up, and trace dimensions to meet the desired electrical and mechanical requirements. Once the design is complete, it is converted into a set of manufacturing files, such as Gerber files, which serve as the blueprint for the fabrication process.

Further reading: How to Design a PCB Layout: A Comprehensive Guide

Fabrication: The fabrication process involves the creation of the physical PCB based on the design files. This process typically begins with a substrate material, such as FR-4 (commonly used fire-retardant composite material made of woven fiberglass cloth with an epoxy resin binder), which is coated with a layer of copper on one or both sides. The copper is then etched away using a chemical process or a mechanical milling process to create the desired trace pattern. For multilayer PCBs, individual layers are fabricated separately and then laminated together using heat and pressure. After the traces are formed, the board is drilled to create holes for mounting components and establishing electrical connections between layers. The holes are then plated with copper to create PTHs or vias. Finally, the board is coated with a solder mask to protect the traces and a silkscreen layer to indicate component placement and other relevant information. Post fabrication, the PCB is treated to prevent oxidation and ensure longevity.

Further reading: PCB Material: A Comprehensive Guide to Understanding and Choosing the Right Materials

Assembly: The assembly process involves mounting and soldering the electronic components onto the PCB. There are two primary methods for attaching components to a PCB: through-hole soldering and surface-mount technology (SMT). In through-hole soldering, components with leads are inserted into the drilled holes and soldered to the traces on the opposite side of the board.

Fig. 3: SMT component soldered on a PCB

Further reading: SMT Manufacturing: Everything You Need to Know

In SMT, surface mounted devices (SMD) components with small metal tabs, called solder pads, are placed directly onto the surface of the PCB and soldered to the traces using a reflow soldering process. SMT is more commonly used in modern PCB assembly due to its higher component density, smaller footprint, and improved performance characteristics. After the components are soldered, the assembled PCB is tested for functionality and quality before being integrated into the final electronic device.

Further reading: PCB Manufacturing Process: Everything You Need to Know

Each stage of the PCB manufacturing process requires precision and attention to detail to ensure the board meets the desired specifications and performs reliably in its intended application. By understanding the intricacies of this process, engineers and designers can make informed decisions that optimize the performance, cost, and manufacturability of their PCB designs.

PCBA: Printed Circuit Board Assembly

Definition and Function

A printed circuit board assembly (PCBA) is a PCB with all the necessary electronic components mounted and soldered onto it, forming a complete and functional circuit. The process of assembling a PCB with its components is known as PCB assembly, and it is a critical step in the production of electronic devices. The primary function of a PCBA is to provide a platform for the electronic components to work together in a coordinated manner, enabling the device to perform its intended tasks.

In more technical terms, a PCBA serves as the electrical interconnect that routes signals between components according to the schematic of the device. It also provides the necessary ground planes, voltage planes, and impedance control needed for stable electrical performance.

Further reading: Components of a PCB: A Comprehensive Guide

The assembly process involves placing and soldering components such as resistors, capacitors, integrated circuits, and connectors onto the PCB. This can be done using various techniques, including through-hole soldering and SMT, depending on the type of components and the design requirements of the device. Once the components are securely attached to the PCB, the assembled board is tested for functionality, quality, and reliability before being integrated into the final product.

Fig. 4: An assembled PCB/PCBA can either be used as a standalone product or as a part of a larger system

The performance of a PCBA is influenced by several factors, including the quality of the components, the accuracy of the assembly process, and the integrity of the solder joints. These factors can impact the electrical characteristics of the assembled board, such as its resistance, capacitance, and inductance, as well as its overall reliability and lifespan. Therefore, it is essential to carefully select components, follow best practices for assembly, and thoroughly test the PCBA to ensure optimal performance and reliability in the final electronic device.

Types of PCBAs

PCBAs can be categorized based on various factors, such as the assembly technique used, the complexity of the circuit, and the intended application. The primary types of PCBAs include through-hole assembled PCBAs, surface-mount assembled PCBAs, and mixed-technology PCBAs.

Through-hole assembled PCBAs utilize through-hole components, which have leads that are inserted into holes drilled into the PCB and soldered on the opposite side. This assembly technique has been widely used for decades and is known for its robust mechanical connections and ease of prototyping. However, through-hole components are generally larger and require more space on the PCB, making them less suitable for high-density and miniaturized designs. Through-hole assembled PCBAs are commonly found in older electronic devices, power electronics, and applications where strong mechanical connections are required.

Surface-mount assembled PCBAs employ SMT, where components with solder pads are placed directly onto the PCB and soldered to the traces using a reflow soldering process. SMT components are smaller and can be mounted on both sides of the PCB, allowing for higher component density and more compact designs. Surface-mount assembled PCBAs are widely used in modern electronics, such as smartphones, computers, and IoT devices, due to their improved performance characteristics and space-saving advantages.

Mixed-technology PCBAs combine both through-hole and surface-mount components on the same board, taking advantage of the strengths of each assembly technique. This approach is often used when specific components are only available in one form factor or when the design requirements call for a combination of the mechanical robustness of through-hole connections and the high-density capabilities of surface-mount technology. Mixed-technology PCBAs can be found in a variety of applications, including industrial controls, automotive electronics, and medical devices.

Fig. 5: Mixed technology PCBA with both surface mount and through hole components

In addition to these, there are several other types of assemblies such as flexible PCBAs, and Ball Grid Array (BGA) PCBAs. Flex PCBAs are designed to bend and flex, making them ideal for applications where space constraints are a concern or where the PCB needs to conform to a particular shape. BGA PCBAs, on the other hand, utilize a surface mount packaging technique for integrated circuits, offering a compact footprint, high lead count, and enhanced thermal and electrical performance. These specialized PCB types are often utilized in devices requiring intricate designs and high flexibility, such as in aerospace, medical devices, and high-performance computing applications.

The choice of which type of PCBA to use depends on factors such as the design requirements, the available components, the desired performance characteristics, and the project's budget. By understanding the differences between these types of PCBAs, engineers and designers can make informed decisions that best meet the needs of their specific applications.

PCBA Manufacturing Process

The PCBA manufacturing process involves several stages, including PCB fabrication, component procurement, and assembly. Each stage plays a critical role in ensuring the functionality, reliability, and performance of the final assembled board. It’s also important to note that the foundation of a PCBA is the PCB; without a PCB, a PCBA cannot be created.

PCB Fabrication: As discussed in the PCB manufacturing process, the fabrication stage involves creating the physical PCB based on the design files. This includes etching the copper traces, drilling holes for through-hole components and vias, and applying solder mask and silkscreen layers. The fabricated PCB serves as the foundation for the assembly process.

Component Procurement: Before assembly, all the necessary electronic components must be procured. This involves selecting and sourcing components based on the design requirements, such as performance specifications, form factor, and cost. Component procurement is a critical step, as the quality and availability of components can directly impact the performance and lead time of the PCBA.

For high-frequency applications, material selection becomes critical. Materials like Rogers or polytetrafluoroethylene (PTFE) laminates are often used to minimize signal loss. Additionally, the manufacturing process may include impedance control measures and multi-stage inspections to ensure signal integrity. 

Assembly: The assembly process involves mounting and soldering the electronic components onto the PCB. This can be done using through-hole soldering, surface-mount technology (SMT), or a combination of both techniques, depending on the design requirements and the types of components used. The assembly process typically involves the following steps:

1. Stencil Printing: A stencil is used to apply solder paste onto the PCB in precise locations where the surface-mount components will be placed. The solder paste contains tiny solder particles suspended in a flux medium, which helps to create strong and reliable solder joints during the reflow soldering process.

2. Component Placement: Using automated pick-and-place machines, surface-mount components are accurately placed onto the PCB, aligning their solder pads with the corresponding solder paste deposits. For through-hole components, manual or automated insertion machines are used to insert the leads into the drilled holes.

3. Reflow Soldering: The PCB, with surface-mount components in place, is passed through a reflow oven, where it is subjected to a controlled temperature profile. The solder paste melts and forms a solid connection between the component pads and the PCB traces. For through-hole components, wave soldering or selective soldering techniques are used to create solder joints.

4. Inspection and Testing: After the assembly process, the PCBA is inspected for defects, such as misaligned components, solder bridges, or missing solder joints. Inspection methods include visual inspection, automated optical inspection (AOI), and X-ray inspection. The PCBA is also tested for functionality and performance using techniques such as in-circuit testing (ICT) and functional testing.

By understanding the intricacies of the PCBA manufacturing process, engineers and designers can make informed decisions that optimize the performance, cost, and manufacturability of their assembled boards. This knowledge can also help identify potential issues and implement best practices to ensure the highest quality and reliability of the final electronic device.

Key Differences between PCB vs. PCBA

Manufacturing Process

One of the primary differences between a PCB and a PCBA lies in their manufacturing processes. While both involve the fabrication of the printed circuit board, the assembly process distinguishes a PCBA from a bare PCB.

PCB Manufacturing: As previously discussed, the PCB manufacturing process involves designing the board layout, fabricating the physical board based on the design files, and applying solder mask and silkscreen layers. The result is a bare PCB with conductive traces and holes for mounting components but without any electronic components attached.

PCBA Manufacturing: The PCBA manufacturing process builds upon the PCB manufacturing process by adding the assembly stage. This involves procuring the necessary electronic components, placing and soldering them onto the PCB using through-hole or surface-mount techniques, and inspecting and testing the assembled board for functionality and quality. The final product is a fully functional circuit with all the required components mounted and interconnected on the PCB.

The distinction between the two processes is essential to understand, as it impacts various aspects of the electronic device's development, such as cost, lead time, and complexity. A bare PCB is less expensive and quicker to produce than a fully assembled PCBA, but it lacks the functionality provided by the mounted components. 

On the other hand, a PCBA offers a complete and functional circuit, ready for integration into the final electronic device, but requires a more complex and time-consuming manufacturing process. By understanding the differences between PCB and PCBA manufacturing, engineers and designers can make informed decisions that best meet the needs of their specific projects and applications.

Components and Complexity

Another key difference between PCB and PCBA lies in the components and complexity of the boards. While a PCB serves as the foundation for mounting and interconnecting electronic components, a PCBA includes all the necessary components already assembled, forming a complete and functional circuit.

PCB Components and Complexity: A bare PCB consists of an insulating substrate, conductive traces, and holes for mounting components. The complexity of a PCB is primarily determined by the layout of the traces, the number of layers, and the density of the interconnections. PCBs can range from simple single-sided boards with a few traces to complex multilayer boards with high-density routing and numerous vias. However, a PCB does not include any electronic components, and its functionality is limited to providing the platform for component assembly and interconnection.

PCBA Components and Complexity: A PCBA includes all the electronic components, such as resistors, capacitors, integrated circuits, and connectors, mounted and soldered onto the PCB. The complexity of a PCBA is influenced not only by the PCB design but also by the number, type, and arrangement of the components. Assembling a PCBA requires careful consideration of component placement, orientation, and soldering techniques to ensure reliable electrical connections and optimal performance. The complexity of a PCBA can impact the assembly process, testing, and troubleshooting, as well as the overall functionality of the electronic device.

Understanding the differences in components and complexity between PCBs and PCBAs is crucial for engineers, designers, and manufacturers. This knowledge can help them make informed decisions regarding the design, assembly, and testing processes, as well as optimize the performance, reliability, and cost of their electronic devices. By considering the specific requirements and constraints of their projects, professionals in the electronics industry can choose the appropriate level of complexity and component integration for their PCBs and PCBAs.

Cost and Time Considerations

Cost and time considerations are crucial factors when comparing PCBs and PCBAs, as they can significantly impact the overall development and production of electronic devices. The differences in manufacturing processes, components, and complexity between the two types of boards contribute to variations in cost and production time.

PCB Cost and Time: The cost of producing a PCB depends on factors such as the type of substrate material, the number of layers, the complexity of the trace layout, and the quantity of boards being produced. Generally, single-sided PCBs are the least expensive, while multilayer boards are more costly due to the additional materials and manufacturing steps involved. The production time for PCBs is typically shorter than for PCBAs, as it does not include the assembly process. However, more complex PCB designs may require longer fabrication times due to the increased number of manufacturing steps and the need for more precise alignment and registration.

PCBA Cost and Time: The cost of producing a PCBA is influenced by the PCB fabrication costs, as well as the costs associated with component procurement, assembly, and testing. Component costs can vary widely depending on the type, quantity, and quality of the components used. Assembly costs are affected by factors such as the complexity of the board, the number of components, and the assembly techniques employed. Additionally, testing and inspection processes can add to the overall cost and time required for PCBA production. In general, PCBAs are more expensive and time-consuming to produce than bare PCBs due to the added complexity and the need for component mounting and interconnection.

Table 1: Summary of key differences between PCBs and PCBAs

When choosing between PCB and PCBA, it is essential to consider the cost and time implications of each option. By understanding the factors that contribute to these differences, engineers, designers, and manufacturers can make informed decisions that balance performance, reliability, and cost-effectiveness for their specific projects and applications. This knowledge can help optimize the development process, reduce production lead times, and ensure the successful completion of electronic devices within budget and time constraints.

Applications of PCB and PCBA

Both PCBs and PCBAs are integral to the electronics industry, underpinning almost every electronic product. Their applications span a multitude of sectors:

• Consumer Electronics: From the smartphone in your pocket to the television in your living room, PCBs and PCBAs are at the heart of these devices. They provide the platform for the microprocessors, memory, and other components that enable the device's functionality.

• Automotive Electronics: Modern vehicles, especially electric vehicles (EVs), heavily rely on PCBs and PCBAs for battery management, energy efficiency, and autonomous driving capabilities. As the shift towards electrification accelerates, these boards play a pivotal role in ensuring optimal performance and safety in EVs.

• Industrial Controls: In factories and industrial settings, PCBs and PCBAs drive the programmable logic controllers (PLCs), motor drives, and sensors that keep operations running smoothly.

• Medical Devices: Whether it's a heart rate monitor, an MRI machine, or a robotic surgical assistant, the precision and reliability of PCBs and PCBAs are vital.

• Computing Devices: The computational power of servers, desktops, and laptops is facilitated by intricately designed PCBAs, which house CPUs, GPUs, RAM, and other critical components.

• Telecommunications: The routers, switches, and base stations that keep us connected, whether through cellular networks or the internet, rely on high-performance PCBAs.

• Aerospace and Defense: In the demanding environments of aerospace and defense, PCBs and PCBAs must meet stringent standards. They play a role in everything from cockpit instrumentation to missile guidance systems.

• Internet of Things (IoT) Devices: The burgeoning world of IoT, encompassing smart home devices, wearables, and industrial sensors, is powered by compact and efficient PCBAs.

While the end-use applications for PCBs and PCBAs are fundamentally the same, the choice between procuring a bare PCB or a fully assembled PCBA often hinges on the project's specific requirements:

• Prototyping and Testing: During the initial stages of product development, engineers might opt for bare PCBs. This allows for manual assembly, easy component swaps, and iterative testing. It's easier to diagnose issues on a bare PCB where components can be manually soldered and replaced.

• In-house Assembly: Some companies possess in-house assembly capabilities. They might purchase bare PCBs and handle the component assembly themselves, giving them greater control over component choice, quality assurance, and production timelines.

• Turnkey Solutions: For businesses that want a complete solution, fully assembled PCBAs are the answer. These are ready-to-integrate circuits, often coming with warranties and quality assurances. They're especially useful for large-scale manufacturing where consistency and reliability are paramount.

PCBs and PCBAs serve similar end-use applications, but the choice between them is dictated by the project's stage, the company's capabilities, and the desired level of control over the assembly process. Making an informed decision between them can optimize costs, enhance product quality, and streamline the production process.

Choosing between PCB & PCBA

Factors to Consider

When deciding whether to use a PCB or a PCBA for a specific project, several factors must be considered to ensure the optimal choice for the application. These factors include:

Design Complexity: The complexity of the circuit design plays a significant role in determining whether a PCB or a PCBA is more suitable. Simple, low-density circuits can often be accommodated on single-sided or double-sided PCBs, while more complex, high-density designs may require multilayer PCBAs with advanced assembly techniques.

Component Availability: The availability of electronic components in the desired form factor (through-hole or surface-mount) can influence the choice between PCB and PCBA. Some components may only be available in one form factor, necessitating the use of a specific assembly technique and, consequently, a particular type of board.

Performance Requirements: The performance requirements of the electronic device, such as signal integrity, power management, and thermal performance, can impact the choice between PCB and PCBA. High-performance applications may require advanced PCBAs with specialized materials, shielding techniques, and assembly processes to meet the desired specifications.

Space Constraints: The available space within the electronic device can also influence the decision between PCB and PCBA. Compact devices with limited space may require high-density PCBAs with surface-mount components, while larger devices with more room for components may be able to accommodate through-hole assembled PCBs.

Cost and Lead Time: The cost and lead time of the project are crucial factors to consider when choosing between PCB and PCBA. PCBs are generally less expensive and quicker to produce than PCBAs, but they lack the functionality provided by the assembled components. PCBAs offer a complete and functional circuit but require a more complex and time-consuming manufacturing process, which can increase costs and lead times.

By carefully considering these factors, engineers, designers, and manufacturers can make informed decisions about whether to use a PCB or a PCBA for their specific projects. This knowledge can help optimize the development process, balance performance and cost considerations, and ensure the successful completion of electronic devices that meet the desired specifications and requirements.

Case Studies

Examining real-world examples can provide valuable insights into the decision-making process when choosing between PCB and PCBA. The following case studies illustrate how different factors influenced the choice of board type in various applications.

Case Study 1: IoT Wearable Device

A company developing a wearable IoT device for health monitoring needed a compact, low-power, and cost-effective solution. The design required a high-density circuit with numerous sensors and wireless communication capabilities. The team chose a multilayer PCBA with surface-mount components to meet the space constraints and performance requirements. The use of a PCBA allowed for efficient assembly, reduced the overall device size, and ensured reliable operation in a compact form factor.

Case Study 2: Industrial Control System

An industrial control system required a robust and reliable PCB to support a variety of through-hole components, such as relays, connectors, and power components. The design needed to withstand harsh environments, including high temperatures, vibrations, and electromagnetic interference. The engineers opted for a double-sided PCB with through-hole assembly, which provided the necessary mechanical strength and durability for the application. The choice of a PCB allowed for a more cost-effective solution while still meeting the performance and reliability requirements.

Case Study 3: High-Performance Computing Server

A high-performance computing server required a complex, high-density circuit to support multiple high-speed processors, memory modules, and network interfaces. The design demanded excellent signal integrity, thermal management, and power distribution capabilities. The team chose a multilayer PCBA with advanced materials, such as low-loss laminates and high-performance solder, to meet the stringent performance requirements. The use of a PCBA enabled the integration of surface-mount components, high-speed routing, and advanced thermal management techniques, ensuring optimal performance and reliability in a demanding application.

Case Study 4: Hybrid Home Automation System

A startup company aimed to develop a home automation system that could be customized based on individual household needs. Their primary product was a central control unit that interfaced with various smart devices, such as lights, thermostats, and security cameras.

Custom PCBs: For the central control unit, the company designed a custom PCB. This allowed them to tailor the board layout to their specific requirements, optimizing space and ensuring compatibility with their proprietary software.

Ready-made PCBAs: For the peripheral devices (like smart light switches or motion sensors), the company sourced ready-made PCBAs from third-party manufacturers. These PCBAs were standardized, cost-effective, and could be quickly integrated into the home automation ecosystem.

By combining custom PCBs with off-the-shelf PCBAs, the company was able to achieve a balance between customization and cost-effectiveness. This approach accelerated their time-to-market while ensuring a high degree of adaptability for their customers.

These case studies demonstrate the importance of considering factors such as design complexity, component availability, performance requirements, space constraints, and cost when choosing between PCB and PCBA.

Conclusion

A PCB provides the structural foundation for component placement and electrical interconnections, while a PCBA is the end result of the assembly process with all components in place. The decision to utilize a bare PCB or a fully assembled PCBA is influenced by design requirements, component availability, performance needs, space constraints, and budget. In certain applications, integrating a readymade PCBA with a custom PCB can offer a unique advantage, allowing for rapid deployment of standard functionalities while retaining the flexibility for custom design elements. This hybrid approach can optimize costs, time-to-market, and design specificity, catering to the multifaceted demands of contemporary electronic applications.

Frequently Asked Questions (FAQs)

What is the main difference between a PCB and a PCBA? 

A PCB is a printed circuit board with conductive material traces but without any electronic components mounted on it. A PCBA, on the other hand, is a PCB with all the necessary electronic components assembled, forming a complete and functional circuit.

When should I choose a PCB over a PCBA? 

You should choose a PCB when you only need the foundation for mounting and interconnecting electronic components, and you plan to assemble the components yourself or through a separate assembly process. PCBs are generally less expensive and quicker to produce than PCBAs.

When should I choose a PCBA over a PCB? 

You should choose a PCBA when you need a fully functional circuit with all the required components mounted and interconnected on the PCB. PCBAs are more complex and time-consuming to produce than bare PCBs but offer a complete and functional circuit ready for integration into the final electronic device.

What factors should I consider when choosing between a PCB and a PCBA? 

Factors to consider include design complexity, component availability, performance requirements, space constraints, and cost. By carefully considering these factors, you can make an informed decision that best meets the needs of your specific project and application.

Can I use both through-hole and surface-mount components on the same PCBA?

Yes, mixed-technology PCBAs combine both through-hole and surface-mount components on the same board, taking advantage of the strengths of each assembly technique. This approach is often used when specific components are only available in one form factor or when the design requirements call for a combination of the mechanical robustness of through-hole connections and the high-density capabilities of surface-mount technology.

References

[1] Macrofab. Engineering Essentials: The PCBA Design Handbook [Online]. 2023 June 6. Available from: https://www.macrofab.com/documents/pcba-design-handbook-2023/

[2] Hu R. PCB Design and Layout Fundamentals for EMC. United States: Independently Published; 2019. Available from: https://www.google.com/books/edition/PCB_Design_and_Layout_Fundamentals_for_E/mXIhzAEACAAJ?hl=en

[3] Williams T. The Circuit Designer's Companion. Netherlands: Elsevier Science; 2004. Available from: https://www.google.com/books/edition/The_Circuit_Designer_s_Companion/0ZWtUEOrpMcC?hl=en

[4] Peterson Z. What is a PCB? [Online]. Altium. 2020 Oct 5. Available from: https://resources.altium.com/p/what-is-a-pcb