Difference Between 2 layer pcb vs 4 Layer pcb
Difference Between 2 layer pcb vs 4 Layer pcb
2-layer and 4-layer PCBs are the two most used types of PCBs. Though you can find other types such as 1,4,6 layered PCBs and so on, the 2-layer and 4-layer styles are the ones that are the easiest to employ in most of the devices or prototypes developed for various purposes. These PCBs’ popularity lies in the simplicity of design, relevance to the products, and cost-effectiveness.
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Further, if you choose between the 2-layer and 4-layer types, you will find the 4-layer PCB more promising to provide better signal integrity and low interference issues. The 2-layer PCBs may prove to be very cost-effective, lightweight, and simple, but it may not fit various devices that require more refined signals to deliver desired outcomes.
2-layer PCBs offer a better surface area for housing the conducting elements just like 4-layer PCBs but prove to be lagging in handling the interference issues. So, let’s understand the difference between these two popular PCB types and pick the one best-suited to user needs.
Things to know between 2- and 4-layer PCBs
If we compare 2 and 4 layer PCBs at the macro level, we will find it easier to work with 2-layer PCB as these deliver more ease of use, better conduction, and simple working support. Still, it is better to check the two types of PCBs on other essential aspects taken one by one in the sections below.
Also read:- what exactly is Prepreg in a PCB
Comparing 2-and 4-layers PCBs based on Stackups
2-layer PCB is relatively easy to demarcate or develop due to its simple design. The topmost layer is called layer 1. Since it performs the task of conduction of the signal, it is also called the signal layer. It is made of copper. The thickness of the copper layer is about 0.0014 in. About 1oz copper is used for making this layer. These are the typical values used to develop a PCB with a final thickness of 0.062 in. approx.
In many cases, the thickness is customized according to the device design. Therefore, these parameters are changed in proportion to the customized dimensions. One can easily infer from the design of a 2-layer PCB is that it is quite simple.
4-layer PCB, as the name suggests, is quite elaborately stacked up. It will have an FR4 core or glass core on which two prepreg sheets will be fit on both the sides length-wise. Two copper sheets further enclose these prepreg sheets on both sides. A cross-section of a 4-layer stackup gives design something like this:
00014 in. wide copper layer – 0.0091 in. wide prepreg layers having a dielectric constant of 4.2 – inner layer 0.0014 in. wide called plane – plane also has a sublayer 0.037 in. wide – inner layer 2 having 0.0014 in. wide copper – prepreg layer 0.0091 in. wide – 0.0014 in. single layer
All these layers in a 4-layer PCB are interconnected at joints using the soldering process. These interconnects placed on the upper and lower outermost copper layers.
Thus, the design or stackup of 4-layer PCBs is more elaborate as compared to 2-layer PCBs.
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Comparison of 2- and 4-layer PCBs on the basis of design
A 2-layer PCB design has more surface area to offer to the designer for housing the conductor pattern. Since it has 2-layers, its surface area is double that of a single layer PCB. All the connections are made through vias that allow routing of traces reaching the other side of the PCB.
For natural reasons, the 4-layer PCB design offers more surface area as compared to a 2-layer PCB. The design of a 4-layer PCB is more elaborate than a 2-layer circuit board and understandably more complex. The prepregs attaching in between the upper and lower outer layers require the application of heat and pressure. These prepregs offer better insulation as these are designed to have a dielectric constant of 4.2. If you want to find the number of layers in any PCB, the simple trick is to count the number of unique conductor patterns. The conductor patterns’ numbers are equal to the number of layers of PCB. Thus, in a typical 4-layer PCB design, you can quickly point out conductor patterns four in number.
Comparing 2- and 4-layer PCB on the basis of functionality
Functionality wise, the 2-layer PCB does not exhibit any propagation delay. Defining microstrip traces on the ground plane becomes a simpler thing to do as there are no hindrances due to fewer layers in the design. The Functionality of a 4-layer PCB may show some problems with impedance or give propagation delays, as the signal needs to deal with more layers. Thus, those devices where the signal delay does not catch much attention can use 4-layer PCBs. Also, ground, VCC layers, and two signal layers offer ample insulation and heat resistance that make these circuit boards ideal for devices used for extended hours.
2-layer and 4-layer PCBs’ comparison based on the cost factor
4-layer PCB features more complexity in its design. Thus, it requires a higher level of expertise and more years of experience to put such design together. Accordingly, the designers charge more for creating a 4-layer PCB than what they do for 2-layer variety. The 4-layer PCB, due to its elaborate design, can achieve an added reduction in distortion and enhancement in propagation levels. Due to high performance delivered through better signal integrity and interference reduced to nil, the high cost of 4 layer PCB design looks justified to the developers. Since 4-layer PCB makes it easier for the developers to achieve outstanding features in the devices, they do not mind paying extra for this type of PCB; they prefer it over a 2-layer PCB.
How 2-layer and 4-layer PCBs perform in the making of Prototypes
Prototyping is not a manual process anymore. There are softwares like Gerber that can make prototyping of both the 2-layer and 4-layer PCBs relatively quickly and easily. Hence, just because you are adding extra layers in a 4-layer PCB prototype, you don’t find the process to be more complicated than for making the 2-layer PCB. The complexity of design does not mean the prototyping becomes more problematic as it makes it almost an automated process, throwing the effort out of the development stage.
Mostly, businesses prefer to outsource the PCB prototyping to professional experts. These experts have a readymade set-up for designing all types of prototypes. So, choosing a professional designer also makes it easy to get the prototype ready on time and in an error-free manner, irrespective of the type of PCB you need to develop. The professional experts employ custom designing tools in their prototyping service. Also, they have functional production lines, an instant online quote service, and support for quick Gerber file uploading. All these features allow users to have both types of PCBs without worrying about prototyping issues.
Therefore, both the 2-layer and 4-layer PCBs perform equally well when people want to develop their prototypes.
Also read:- PCB Schematics vs PCB Designs
When should I choose 2-layers PCB vs 4-layers PCB?
Choosing between 2-layer and 4-layer PCB requires you to take into consideration some of the essential requirements. So, take a look to find when the option from 2 layer PCB or 4 layer PCB can help:
- The maximum functionality requirement in limited space: Device designing requires deciding about the maximum size of components used internally. PCB, which is smaller in size and quite enriched in functionality, is a 4-layer PCB. So, those devices, compact but enriched in functionality, can be designed better with a 4-layer PCB.
- More complex functionality in devices: 4-layer PCBs offer good support for devices designed to deliver complex and multiple functionalities. Therefore, 4-layer PCB makes the right choice when you want devices to be innovative in functioning.
- Better durability of devices: 4-layer PCBs support better durability in the devices. The devices with 4-layer PCBs have a better shelf-life. These continue to perform like fresh because of the robust functioning of 4-layer PCBs.
- Affordability of devices: When it comes to controlling the cost of a device, 2-layer PCB can help achieve the aim better. Since 2-layer PCBs do not involve high development cost, using this type of PCB is suitable for low budget devices.
- The quick development of devices: When you need to design devices on short notice, you can quickly meet the deadline by employing a 2-layer PCB. A 2-layer PCB is faster to achieve due to more straightforward design; therefore, for quicker rolling out of a device, pick this option.
Apart from these factors, you have to consider the operation frequency, signal flow design, and density requirement. All these considerations also define the need of picking based on 2 layer PCB vs. 4 layer PCB comparisons.
To conclude,
2-layer and 4-layer PCBs differ in the complexity level of their design. These also differ in thickness and time required for the development. Also, these PCBs’ cost differs as 4-layer is more complex and requires more quantity of materials. So, 4-layer PCBs prove to be costlier. However, 4-layer PCBs prove to be a better option because they enable including lots of functionalities in the device. If we consider the similarities, these perform equally well in the prototype development process due to the availability of the software and professional designing services.
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