How Much More Expensive Is 4 Layer PCB?

02 February 2024
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In the modern age of technology, there's a growing demand for advanced PCBs to power computers, home appliances, industrial machinery, and other electronic devices/equipment. One of the most popular options is the 4 layer PCB. As its name suggests, this printed circuit board has four layers, which offer various benefits, including the ability to design complex, integrated circuits.

However, regarding the price point, a cheap 4 layer PCB is among the most moderately priced circuit boards you can find. Therefore, it's an excellent choice for manufacturers looking to reap the benefits while managing costs more efficiently.

In this post, we'll discuss how much more expensive a cheap 4-layer PCB is than other types of PCBs, including single-layer (1L) and double-layer (2L) variants. But before we dive right into the details, we'll share an overview of a 4 layer PCB.

What Is a 4-Layer PCB?

A 4 layer PCB is a printed circuit board with four layers of conductivity wedged between two layers of insulation (substrate). All these layers combine to create a functional but incredibly cheap 4 layer PCB that enhances signal strength and overall quality. More importantly, it offers superior thermal regulation, which is crucial for modern electronics in terms of shelf life and performance.

Understanding the Anatomy of a 4L PCB

Below are the four layers laminated together to create a 4-layer printed circuit board:

1. Top Signal Layer

The top-most layer of a 4 layer PCB contains most of the electrical components, including:

Capacitors
Resistors
Integrated circuits, etc.

These components are connected by copper traces and solder masks that carry electrical signals throughout the device.

2. Ground Plane

The ground plane is the circuit's first inner layer. It distributes power and ground connections throughout the PCB with a low-resistance return path, reducing noise and enhancing signal strength and stability.

3. Inner Signal Layer

The third layer is a second copper-based signal layer used for routing signals that require controlled impedance, mostly analog frequencies and high-speed data lines.

4. Bottom Layer

Finally, the bottom layer or core serves as the board's foundation and comprises copper traces that mirror the top-most layer's functionality and provide more signal routing.

Common Applications of 4 Layer PCBs

Here are the most common use cases of a 4 layer PCB:

1. Consumer Electronics

The most common use of 4 layer PCBs is to create complex circuits for common devices like smartphones, digital cameras, laptops, and gaming consoles. Manufacturers prefer 4L boards for these devices to enhance signal integrity while minimizing electromagnetic interference (EMI).

2. Industrial Control Systems

Modern industrial machinery and equipment need reliable PCBs, such as programmable logic controllers (PLCs), automatic conveyor belts, and packaging bots, to function optimally. A 4 layer PCB enhances component routing, allowing manufacturers to organize and synchronize their circuitry more flexibly.

3. Automotive Electronics

4L circuits are commonly used in modern vehicles. Manufacturers use it to design components like engine control circuits, infotainment systems, advanced safety features, and self-driving enabling equipment.

4. Data Storage Devices

High-capacity data storage devices like solid-state drives (SSDs) and storage controllers often use 4-layer PCBs. These boards ensure data transfers are efficient and performance is reliable, making them essential for the smooth operation of storage solutions in various applications.

5. Communication Systems

Wireless communication devices like routers, modems, and transceivers frequently rely on 4-layer PCBs. These boards optimize signal routing, minimize interference, and improve overall performance, enhancing the reliability and effectiveness of wireless communication technologies.

Factors Affecting the Cost of PCB in Terms of Number of Layers

Before comparing the costs of 4 layer PCBs with others, we need to understand the underlying factors contributing to the differences. Here are the main ones:

1. Materials

The more layers there are, the more FR-4 substrate, copper, and other raw materials are used for the printed circuit board. The difference between a cheap 4 layer PCB and an expensive variant usually falls to the quality of material used.

2. Manufacturing Complexity & Equipment

The number of layers also influences the complexity of manufacturing processes. The more layers, the harder it is to align, laminate, and drill different components. Moreover, adding layers calls for more advanced and costlier tools and machinery for manufacturing.

3. Design Complexity

Signal routing is among the most important functions of a PCB. The more layers a circuit has, the more additional layers it needs for efficient routing.

4. Manufacturer

4 layer PCBs are manufactured all around the world. Therefore, their prices can vary significantly, depending on the quality, resources available, market competition, and other factors. So, you can expect to find them anywhere between $10 and $100. However, higher-end variants for more complex applications could be more expensive.

How Much More Expensive Is 4 Layer PCB than 1-Layer, 2-Layer, Rigid, and Other PCBs?

1. 1-layer PCBs

One-layer PCBs are generally the most affordable, costing roughly 30% to 50% less than a two-layer PCB. This cost difference is due to their simpler manufacturing process and fewer materials. These single-sided boards are suitable for less complex designs where the advantages of additional layers are not necessary. Hence, manufacturers use them for basic applications, including LED lighting, power supplies, and low-cost electronics like calculators, toys, and remotes.

2. 2-layer PCBs

Two-layer PCBs fall in a moderate cost range, about 20% to 40% less expensive than their four-layer counterparts. The increased cost of one-layer PCBs stems from the added manufacturing complexity with conductive traces on both sides, making them ideal for the abovementioned applications.

3. 4-layer PCBs

Four-layer PCBs are generally the most expensive, about 30% to 50% pricier than a two-layer PCB. This higher cost is attributed to the greater manufacturing complexity and advanced fabrication processes.

Conclusion

Printed Circuit Boards (PCBs) are indispensable to modern electronics. They provide a structured way to connect electronic components, which is key to ensuring device or equipment functionality.

A 4 layer PCB is one of the go-to choices for modern manufacturers looking to balance performance and design flexibility. These variants allow them to design more complex circuits while improving signal integrity and power distribution.

These PCBs are more cost-effective than rigid-flex, 6-layer, and more advanced circuit boards.