PCB or printed circuit board and PCBA or printed circuit board assembly. If you have ever done any electronics manufacturing, you may not be sure of the difference between a PCB and a PCBA. While the two terms are commonly interchanged, they are different from each other. Let’s help explain the difference between a PCB and a PCBA.

What are PCB and PCBA?

1. PCB (printed circuit board):
   The printed circuit board is the base for all the electronic products. Made of an insulating material, such as fiberglass or resin, with a thin layer of copper on the other side to conduct electrical signals, it provides a platform on which to connect different electronic parts and components. So, you can think of the PCB as the “skeleton” of the circuit board. The circuit board that does not have components on its surface. In short, PCB is nothing but the base for all electronic components to allow them to connect and communicate.
2. PCBA (printed circuit board assembly):
   PCBA is the finished and assembled circuit board, meaning that after the PCB is built, electronic components like resistors, capacitors, diodes, integrated circuits (IC), and more are added and soldered to the circuit board. The PCBA is what does the actual task after it is assembled and soldered. At this point, a PCBA is ready to go and perform specific electrical tasks.

Main differences between PCB and PCBA

1. Structure and composition:
   PCB: PCBs have just the circuit pattern and pads with no components on the board surface. PCBs are generally made from insulating materials like fiberglass resin or fiberglass-reinforced epoxy with a layer of copper on the other side to conduct electrical signals.
   PCBA: A PCBA is a fully assembled circuit board. The basic PCB with the circuit pattern and pads will also include the different electronic components and all are soldered onto the PCB board. A PCBA is fully operational after the assembly and can carry out all electrical tasks.
2. Functionality:
   PCB: A PCB is, for all intents and purposes, a blank circuit board. That means it can do nothing of itself.
   PCBA: A PCBA is a fully functional circuit board. After all of the components have been added and soldered to the PCB, the PCBA can perform a range of electrical tasks like signal transmission, power conversion, and data processing. A PCBA is the PCB after it has been made functional.
3. Manufacturing process:
   PCB: The process to make PCBs usually involves circuit design, printing, and etching.
   PCBA: A PCBA takes a PCB even further. After the PCB is made, then electronic components are added using surface-mount technology (SMT) or through-hole technology and soldered in place.
4. Cost and production time:
   PCB: PCBs are quick and relatively inexpensive to produce.
   PCBA: PCBA takes longer to produce and are more expensive.
5. Quality control:
   PCB: Quality control of PCBs is focused on the circuit’s quality, the copper’s integrity, and the quality of pads on the PCB.
   PCBA: In addition to the PCB, PCBA also must ensure the quality of soldering, placement, and electrical performance. Automated optical inspection (AOI) and X-ray inspection of PCBA are two common and effective methods.
6. Applications:
   PCB: PCBs are used primarily during the prototype development phase of the production cycle. If you are custom design services, you might also be using PCBs.
   PCBA: Once fully assembled, PCBAs are used for electronic devices, computers, automotive electronics, industrial electronics, medical equipment, and everything in between. The fully assembled PCB is what is in all of these devices and applications.

How to choose PCB and PCBA

It can be useful to know how to choose PCB and PCBA for your electronic needs. Whether you are prototyping, manufacturing in bulk, or doing custom PCB and PCBA, understanding PCB and PCBA will help your product be effective and successful and even save you money. Here is how to choose PCB and PCBA.

1. Choosing PCB:
   A good PCB can help make sure your final product will give stable and quality electrical connections and physical support for the components on the circuit board. Here are some things you can use to choose PCB:
   Material selection
   FR4 (fiberglass resin), CEM-1 (composite material), and many more options like Polyimide (PI) and ceramics can all be used for PCB. Choosing the right PCB material will help you ensure the best electrical performance, heat resistance, and mechanical strength.
   Layer count
   The number of layers of PCB used will affect the size and cost. Single and double layers are relatively inexpensive and are often used for simple circuit designs. Multi-layer PCBs like 4 layers PCB, 6 layers PCB, or even more, are often used for high-density circuits and high-speed signal circuits.
   Size and thickness
   Size is an important consideration, as smaller PCBs are often needed in portable devices. Larger PCBs might be better for large equipment or for power. The thickness can also impact the board’s mechanical strength and heat dissipation.
   Surface finish
   The surface finish is applied to the PCB and can be options like OSP (Organic Solderability Preservative), metal spraying, and gold plating. Choosing the right surface finish will ensure high-quality soldering and reliable electrical connections.
   Signal and power
   Signal and power needs might also be a concern. If your board needs to support high-speed signals or high-power signals, then the right PCB design can help. Options like the PCB signal integrity, EMI, PCB layout, and trace routing can help ensure the right performance for your application.
2. Choosing PCBA:
   PCBA is the fully assembled PCB. So, in addition to choosing PCB, also consider choosing right electronic components, soldering process, and product testing. Here are some tips to consider when choosing PCBA.
   Component selection
   The performance and quality of all of these components can directly affect the performance and quality of the final product. Special components can also narrow down the choice of products, such as special requirements for low power consumption or special high-frequency support.
   Soldering process
   Hand soldering, wave soldering, reflow soldering, and selective soldering are all common soldering options. Reflow soldering is the most common method for SMD, while hand soldering is more for special components, usually for small production runs or more complex PCBAs.
   Assembly and testing
   Making sure all of the components are properly installed on the PCB and through comprehensive testing, the assembled PCB is fully functional and operational. The more components added to the PCB, the more extensive the testing is usually. Options for testing include Automated Optical Inspection (AOI) and X-ray inspection and functional testing. The good assembly manufacturer should have strong quality control to ensure the PCBA works as it should.
   Production volume and customization
   Production volume will also make a difference. A smaller batch production usually has lower initial costs and usually has a higher unit price. For larger production runs, the price is usually lower, but it also requires a more complex production and testing process. If your application requires customization, such as the medical industry or automotive industry or aerospace industry, also make sure the manufacturer can provide.
   Functionality and reliability
   For the application of a product, according to its specific function, we should choose a PCBA with high reliability and stability. For special applications such as automotive, medical devices, industrial electronics, etc., PCBA will have higher requirements for reliability, which must have more stringent testing and certification (ISO9001, ISO14001 certification).
3. Key points when choosing PCB and PCBA:
   It is important to note that when selecting PCB and PCBA, the two need to be considered in light of the other options. The product’s end use, budget, production schedule, and requirements for the device or machine to be used are all important when choosing both PCB and PCBA. Here are some tips to keep in mind:
   Understand the design requirements:
   Know the needs of the product that PCB and PCBA will be used in. Do you need a product to support high-frequency signals or high-power signals, or is it just for simple signal transmission? These design choices will impact the material, process, component selection, and production processes.
   Long-term supply chain and quality control
   It is important to ensure that the supplier has the ability to provide the same high-quality products over a long period of time with a tighter production schedule.
   Cost and performance:
   It is important to consider cost vs. performance for mass production projects. For example, it is not wise to sacrifice quality and functionality just because the initial cost might be too high. On the other hand, the right PCB materials and production processes will allow you to optimize the cost without sacrificing performance and quality.
   Lead time and delivery schedule:
   This is another important consideration. If your product needs to be ready quickly, then shorter production times and faster delivery are essential. On the other hand, if your product is not time sensitive, you can use cheaper or less expensive providers that may take longer.
   Conclusion
   In conclusion, the PCB and the PCBA are important parts of electronics manufacturing and need to be considered during the process. A PCB is the foundation for any electronics that need electrical signals and components to connect. PCBA is a more finished product that is a fully assembled PCB with components, testing, and soldering all in place. In choosing PCB, several considerations can make a difference in the end result. Selecting a PCBA is even more important since it is a finished product. When considering PCB and PCBA, it is important to keep in mind all of the aspects of the choices and choose wisely.
   If you want to know more about PCBs or PCBAs, do not hesitate to contact us.

FAQs

1. Why is it important to understand the difference between PCBA and PCB?
   Understanding the difference between PCBA and PCB is important because it can help you make better design and production decisions, which in turn helps your project be successful and saves you money. By making the wrong choice, you can end up making a mistake and needing to pay for an entirely new product. The PCB is a great option for early product development or custom circuit board services. PCBA, on the other hand, is best for fully assembled and tested boards ready to do the specific work needed.
2. Why is the production cycle for PCBA longer?
   PCBA has a longer production cycle because of all of the added work and complexity after the PCB is made. Each individual component on the board needs to be placed and soldered, and the board needs to be inspected and tested to ensure that the board works correctly. Quality control like automated optical inspection or X-ray inspection will need to be run to make sure the PCB is complete and working.
3. When should you choose a PCB and when should you choose a PCBA?
   You should choose a PCB when you are in the early development phase or just want a platform for connecting your components. This can be for prototyping or for custom circuit board services.
   A PCBA should be chosen when you are building out a fully assembled, ready to go product that needs to do specific work. In other words, a PCB is for developing, and a PCBA is for production-ready products that are functional and ready to work.