What You Need to Know About the 6 Layer PCB

You may have believed that the 6 Layer PCB is a type of Printed Circuit Board (PCB) with six (6) layers. While that appears to be what the name deduces, it is not so. On the contrary, the 6 Layer PCB is a type of circuit board with four (4) major layers and two (2) additional layers that serve as the signal layers.

In this article, you will learn more about the 6 Layer PCB stackup, why it is better than the four (4) layer circuit board and some of the benefits of choosing it.

How the 6 Layer PCB Compares to the 4 Layer PCB

The four (4) layered PCB, which is the circuit board layer design that comes before the 6 Layer PCB, is common for applications that require less resources, such as higher power requirements.

However, when your PCB applications begin requiring more resources, such as higher power needs, more Input and Output (I/O) counts, as well as high-speed solutions; it is a signal that you need to step up on the layer count.

The next layer of circuit boards after the 4 layer PCB is the 6 Layer PCB and that is what we are discussing in this article.

As a “step up” or improved variant of the 4 layer PCB, the 6 Layer PCB helps to match the high-speed, high power and several I/O count needs. It is also one of the primary PCB layer designs that feature improved signal integrity, as offered by the two (2) extra layers, routability and improved EMC.

6 Layer PCB Structure: How is it Formed?

If you are to buy the 6 Layer PCB, it is expedient that you understand how it works. The structural design of the layers is an important consideration.

The first thing you must note is that the 6 Layer PCB retains the original four layers that accrue to the 4-layered PCB. In addition to that, it adds two more layers, that double as the signal layers.

These additional layers are positioned between the planes. The following is a breakdown of all the layers you can find in the 6 Layer PCB:

  • Ground plane layer
  • A power plane
  • A bottom signal layer
  • Inner signal layer
  • Top signal layer and;
  • Second inner layer

However, the above being the standard configuration of the 6 Layer PCB doesn’t mean that all designs follow suit. Depending on the manufacturer and the target applications, variations can also be created.

In that light, below are examples of some variants of the 6 Layer PCB stackup:

Stackup for Shielding Purposes

One of the major reasons for introducing the 6 Layer PCB is to offer better features than the 4 layer PCB does. These features range from the improved signal transmission and the high-speed of the targeted applications.

To actualize the aforementioned and to provide additional layers of protection for the circuit (in the form of shielding); the following 6 Layer PCB stackup was invented:

  • Top signal layer
  • Bottom signal layer
  • Ground plane layer
  • Single power plane layer
  • Inner signal layer and;
  • Second inner layer

6 Layer PCB Stackup for Improved Capacitance

It is pertinent to mention that the second stackup of the 6 Layer PCB that we just talked about is imperative for improving the signal transmission and solidifying the circuit’s protection. However, it lags in the provision of better capacitance, as a result of the wide margin (separation) between the ground and power layers.

To resolve that separation and to improve the capacitance capabilities of the 6 Layer PCB, a new stackup format can be followed. Below is the structure:

  • One top signal layer
  • Ground plane layer
  • An inner signal layer
  • Power plane layer
  • One ground plane layer and;
  • A bottom signal layer

Reasons for Choosing the 6 Layer PCB

If we are asked to mention some of the reasons why the 6 Layer PCB is better, one of the things we would probably talk about is the excellent routing capabilities. We may also hint on the improved signal transmission and the extra layer of protection it adds to the circuit board.

However, the benefits of the 6 Layer PCB far outweigh those. Below are some of the additional reasons why the 6 Layer PCB is better, especially when it is placed side-by-side with the 4 layer PCB.

1. Signal Separation

In addition to improving the speed of transmitting signals, the 6 Layer PCB also helps to separate these signals so they don’t “conflict.”

It is expedient to mention that the signal separation capability comes in handy for high-speed circuit boards, which also have a higher Input and Output (I/O) counts.

2. The 6 Layer PCB Offers Improved Durability

One of the main benefits of the 6 Layer PCB is that it improves the durability or long-lasting possibility of the circuit board.

This happens because the stackup guidelines usually make provisions for the implementation of different protective materials and insulation layers between the circuits.

3. 6 Layer PCB Weighs Less

One may have expected the 6 Layer PCB to weigh more, due to the higher layer counts and the number of components that will be used.

It is rather a less-weighing circuit board, mainly because of the use of lightweight components. Besides, the connection process is simplified, as the 6 Layer PCB doesn’t necessarily need a lot of connectors to link or connect the components.

4. It has a Simplified Layout

The layout process of the 6 Layer PCB, as well as its connection processes are simplified. While reducing the number of connectors needed to link the parts, the 6 Layer PCB also uses a simplified layout, which helps to create a lot of space inside the board.

5. 6 Layer PCB is Ideal for Mixed Signal Routing

Are you working on a circuit board that uses different signals, especially the analog and digital signals? If so, it is better to use the 6 Layer PCB for the fabrication and here’s why:

By using the 6 Layer PCB, you can have an entire surface layer dedicated to the analog interfaces, while the extra/additional (internal) layer, can be used for enabling the slower routing of the digital interface.


In summary, the 6 Layer PCB is an improved version of the 4 layer PCB, and hosts a number of innovations, ranging from improved signal transmission, support for high-speed applications and mixed signal routing capabilities.