4-Layer PCB: How Do They Differ from Other Multilayer PCBs

As the demand for advanced tech, high-speed, high-performance, and miniature devices has risen, the need for complex and small-sized printed circuit boards (PCBs) has also grown. So, PCBs have become tinier than ever before, are available in various configurations, and can be customized based on application requirements. Therefore, varieties of multilayered PCBs are being developed. Among them, 4-layer PCBs are commonly used across applications. These PCBs are a key part of various electronics, as well as, communication appliances. Would you like to know more about them, especially the stack-up structure and their types? What benefits they offer and what are their application areas? Read through the post, and you will get the answers to all the questions.

What is a 4-Layer PCB?

Among all the multi-layered types, the 4-layer printed circuit board (PCB) is the most common. The stack-up of a 4-layer PCB is quite robust, and it comprises Top Layer, Inner Layer 1, Inner Layer 2, and Bottom layer to route electrical signals. Both the inner layers (Inner Layer 1 and 2) are placed in between the top and bottom layers. Therefore, a 4-layer PCB means 2 signal layers + a positive voltage layer (VCC layer) + a ground layer (GND layer) or 3 signal layer + GND layer. In a 4-layer PCB design, more surface area is available for traces. Thus, this design structure offers excellent routing for low, as well as high-speed signals.

4-Layer PCB Stack-Up Types

When you approach a 4 layers PCB manufacturer, they will offer you these two standard structures of a 4-layer PCB. Here VCC and GND layers are organized on the basis of application requirements.

  • Type 1: Signals – GND – VCC – Signals: In this type of 4-layer PCB design, the top layer is preferably the key signal. As far as the layer thickness is considered, the impedance control core board should not be too thick. This helps reduce the distribution impedance of the ground plane and the power supply.
  • Type 2: GND – Signals – Signals – GND: This stack-up structure is perfect, if you don’t want to connect all types of ground pins using via routes. To improve the EMC performance of the circuit board, it is always a good idea to space the signal layers close to the planes. Make use of a large core between ground and power plane for maintaining the overall thickness of the substrate.

Key Advantages of a 4-Layer PCB

Owing to their beneficial features, 4-layer PCBs are widely used in many electronic applications. Some key benefits offered by these multilayered PCBs are as follows:

  • Smaller and Quality-Driven Designs: This is one of the important reasons for using a 4-layer PCB. Owing to their multilayer design structure, they are inherently small in size than single-sided printed circuit boards. This is beneficial for modern electronic devices such as smartphones, tablets, and laptops. As it is a multilayered design, it requires a thoroughly planned design and precision, when mounting components. This helps in reducing unwanted errors and ensures high-quality results.
  • Excellent Durability: As described above, these circuit boards not only withstand their weight but also handle applied pressure and heat that bind them together. Additionally, owing to the multiple layers of insulation between circuit layers, their durability increases.
  • Higher Assembly Density: These printed circuit boards increase the assembly density by incorporating several layers into one single board. The interconnection between close quarters allows circuit boards to be more connective.
  • Lightweight Construction: In a 4-layer PCB, multiple connectors are required to interlink or connect separate single, as well as double-layered circuit boards. It helps in simplifying the circuit design, and reduces its weight.

Applications of a 4-Layer PCB

The key advantages of these circuit boards contribute to their popularity across diverse industries. Following are some important applications where these circuit boards are widely used:

  • Heart Monitors
  • Computers
  • GPS Technology
  • File servers
  • Mobile Phones
  • Data storage
  • Signal transmission
  • Weather analysis
  • Space probe equipment
  • X-Ray Equipment
  • Atomic accelerators
  • Cat scan technology
  • Fiber optic receptors
  • Central fire alarm systems
  • Cell phone transmission and repeaters

If you are looking for a 4-layer PCB for your application, then it is important to source them from a reliable 4 layers PCB manufacturer who understands your application requirements effectively. PCB HERO is counted among one of the leading 4 layers PCB manufacturers in the China. The company produces various types of multi-layered PCBs, which are RoHS compliant. Over the years, the team of highly experienced and skilled experts at the company has been designing high-quality 4-layer printed circuit boards for use in modern devices, electronics equipment, and so on.