4 Layer PCB

4 Layer PCB Meaning

4 Layer PCB means the PCB include four layers of conductive copper layers. The top layer, bottom layer are both copper, besides, there are still two inner layer are copper material. Between the copper layer there would be Pre-preg material for separating them.

Why some time use 4 layer PCB better than 6 layer PCB, 8 Layer PCB or 10 layer PCB?

A circuit board can be designed and constructed in a variety of ways. There are many additional materials besides FR-4, which is a common material group used as the PCB substrate. Normally, circuit boards are constructed by etching away excess copper, although additive methods are becoming more and more common. In addition, a circuit board’s layer count might vary, ranging from a single or double-sided board to a multi-board design with four, six, eight, or more layers.

Performance and cost are the two main factors that determine the manufacturing method, the materials, and the layer arrangement. It goes without saying that we want the circuit board to perform at its peak while also being produced for the lowest possible cost. But each of those elements has a significant impact on the others.

A double-sided board cannot accommodate high-density, high-speed designs with thousands of interconnects, nor can the board be configured to support the performance of the electronics. Even though the designer has plenty of room to spread out a ten-layer board for a straightforward design, it doesn’t make financial sense to invest in that many layers when less will suffice.

The ideal PCB layer configuration method must be developed by the design team, and in many circumstances, a 4-layer circuit board will enough. The 4-layer circuit board has many different aspects that need to be taken into account, beginning with a comprehension of all the requirements that will be placed on the board.

When design the 4 layer PCB you should consider below factors:

Working environment: The setting in which the board will be expected to operate will have a significant impact on how it is designed. The materials used to fabricate the board may need to be changed, which will modify how it is constructed, depending on the extreme temperatures or high moisture situations.

Board shape and size: The size and shape of the board can necessitate a change in board layers depending on where it will be mounted in order to fit all of its trace routing. The size and shape may also have an impact on how the board is made.

Technique: The layer stackup of the board will be determined by the kind of components used and the speed of the circuitry. In order to route out of all of its pins, large, high-density portions like BGA footprints may need additional layers.

Signal: The number of ground plane and routing layers may need to be increased due to design specifications for controlled impedance routing and EMI shielding, depending on the type of technology used.

Power: A strong power delivery network on the board can require more layers, depending on the power requirements.

Manufacturable: By reducing the trace widths and clearances to fit them into fewer layers, it may become impossible to construct the board without incurring a hefty cost in manufacturing time.

Cost: Building a four-layer board vs a six-layer board can cost more money by up to 40%. This increase is a powerful incentive to maintain the design’s layer count low as long as it is feasible to manufacture.

Performance: Even if configuration adjustments are necessary to achieve this, the board must function in accordance with its operating requirements.

The Stackup of 4-Layer PCB

For designers accustomed to having more room at their disposal, laying out a 4-layer printed circuit board might be quite difficult. 

They might wind up sharing space with copper pours and large traces for power delivery instead of having layers specifically for routing. Here are some specific design factors for a 4-layer PCB stackup to bear in mind.

Grounding

For the optimum signal integrity of the design, circuit board signals, especially high-speed signals, must have a clear return channel. All transmissions, whether they are digital, analog, or power signals, must meet this condition. This requires creating a special ground plane on one of the four internal layers of the board in order to accommodate it. The design will quickly run out of useful space with the outside layers of the board being used for component placement and the final inside layer being used for signal and power routing. However, it is crucial that the ground plane not be divided in order to offer a clean return path and minimize or completely get rid of EMI in the design.

Power

Today’s designs use a lot of components with various voltage level needs. The designer may find it difficult to route all of these voltages on a 4-layer board while keeping a clean power delivery system due to these power requirements. Typically, split planes and wide traces will be used in conjunction to route power. In order to give bypass caps the quickest and most direct route to their designated supply pins, location and routing must also be taken into account.

Escape Routing

This is where a 4-layer circuit board layout can get really complicated. A large-scale BGA component will require more layers for the escape route the more rows of pins there are. The next rows of the part must be connected by a via while the outer rows of the part can be routed out. A 4-layer board will eventually run out of layers needed to successfully route out of a big device.

Trace Routing

Today, mixed-signal designs are widespread, and even a 4-layer board must obey their routing requirements. For a mixed-signal design, a continuous ground plane is necessary. Maintain as much isolation as possible between digital and analog circuits by avoiding routing through gaps in the reference ground plane. Remember that you probably won’t have a separate internal layer for routing; therefore, planning for routing, component placement, and escape routing is necessary to guarantee that there is enough room for everyone.

Heat Dissipation solution

It is a good idea to use an internal power plane to offset the internal ground plane in order to retain the symmetry of the board throughout fabrication and assembly. However, because a routing layer is required, you can be forced to mix large traces or split power planes with standard signal routing. Ground vias can be used to thermally balance systems by transporting heat from large components down via the ground plane.

You must make use of all the features offered by your PCB design tools in order to keep track of all the requirements essential to successfully layout a 4-layer circuit board. We’ll then have a look at some of the functions and tool features that can be most useful.

4-Layer PCB Benifits

There are many benifits of using 4 layer PCB, we list some below:

This is among the crucial justifications for utilizing a 4-layer PCB. These printed circuit boards are naturally smaller than single-sided printed circuit boards because of their multilayer design structure. This is advantageous for current electronic gadgets including computers, tablets, and smartphones. Being a multilayered design, it necessitates meticulous planning and accuracy while installing components. This promotes quality control and lowers unintentional errors.

Durability: As previously mentioned, these circuit boards can endure their weight as well as the pressure and heat that are used to bond them together. Their durability also rises as a result of the numerous insulating layers between circuit layers.

Higher components Density: By combining multiple layers onto a single board, these printed circuit boards raise the assembly density. Circuit boards might be more connective due to the near proximity of the interconnections.

Light weight: Multiple connectors are needed in a 4-layer PCB to interconnect or connect different single- and double-layered circuit boards. It facilitates weight reduction and circuit design simplification.

4-Layer PCB application:

4-Layer PCB is very popular. They can be used to make a lot of different equipment, we list some products below:

1. Cell phone transmission and repeaters
2. Central fire alarm systems
3. Fiber optic receptors
4. Cat scan technology
5. Atomic accelerators
6. X-Ray Equipment
7. Space probe equipment
8. Weather analysis
9. Signal transmission
10. Data storage
11. Mobile Phones
12. File servers
13. GPS Technology
14. Computers
15. Heart Monitors

How do I order 4 layer PCB?

If you want to acquire a 4-layer PCB for your application, it’s crucial to do your research and choose a reputable manufacturer who fully comprehends your needs. One of the top makers of four-layer PCBs is INTOPCB. The company manufactures a range of RoHS-compliant multi-layered PCBs. The company’s staff of highly qualified and experienced experts has been designing premium 4-layer printed circuit boards for use in contemporary gadgets, electronics equipment, and other things for many years. They can offer you good customer service, a low price, and timely delivery of your PCBs. They also have a good reputation.