2 Layer Print Circuit Board(PCB) Manufacturer - NextPCB

What is a 2 Layer PCB?

2 layer PCB is the most common type of PCB design. This layer is also a double-sided PCB since they have electronic components on both sides of the board. Thus, the double-sided PCB has the proper conductive layer on both sides. 

Bonding the two Copper layers, including dielectric materials, can fabricate 2 layer PCB. FR-42 and FR-44 are the two commonly used dielectric materials. The copper layers on both sides of the board help to carry the electrical signal. This property makes the 2-layer PCB suitable for high-speed applications. You can use the double-sided PCB for the product or design with simple to intermediate circuit complexity levels. It is one of the most economical choices in various applications. It can handle more complicated devices and circuits than single-sided PCBs, but it is quite challenging to handle the complex circuitry of this double-layer PCB. Some of the complex circuity includes LED lighting, car dashboard, industrial controls, vending machines, etc. Double-layer PCB provides twice much space compared to single-layer PCB for the components.

2 layered PCBs have a solder mask on both sides of the PCB board. To have the proper conductivity on the circuit board, holes for each component required good plating. These holes are the ones that attach one side of the circuit to the other circuit side. It has the components soldered on both sides, forming a double-layer circuit. Thus the 2-layer PCB is also known as a double-sided PCB. 

2 Layer PCB Stack Up

You can stack 2-layer PCB in 5 layers: Solder Mask, Top layer, Core, Bottom layer, and lower solder mask. The first layer, or the top layer, is the signal layer. Both the top and the bottom layers are copper layers. 

• Inner Layer

The inner layer of this 2-layer PCB is the copper layer. Most of the vias lie in this layer. These vias connected are the tiny hole that properly connects the top and the bottom layers. It helps the electrical signals flow from one layer to another.

• Ground Plane

The ground plane helps in reducing the noise in the electrical signal. Thus ground plane plays an important role in returning electrical signals. In addition, it also helps distribute the proper amount of heat and uses it as a power layer in the circuit board.

• Signal Layer

The signal layer carries the electrical signal for the circuit. The 2-layer PCB contains signal layers, one for the top and one for the bottom. You can use this layer for routing the external signals on the board. In contrast, you can use the bottom layer for the internal routing of signals. 

• Power Layer

Using power layers, you can distribute power across the board. You can also send ground signals through it. 

• Solder Mask Layer

The solder mask layer is the thin material layer that covers most of the exposed copper. In addition, the solder mask also protects the copper from corrosion and oxidation. 

• Silkscreen Layer

It is a thin layer of material used to print the legends on the board. You can also print the name of the board and the number.

What is the Thickness of 2 Layer PCB Stack up?

PCBs with two layers can range from 0.010" to 0.060". The thickness of this PCB board depends on the used dielectric materials and the component's size mounted on the board. The thickness of the panel is proportional to the crosstalk reduction between the signal traces. It means the more the thickness of the board, the less will be the crosstalk on the signal.  

Dielectric or the insulating materials between the conducting layers determines the thickness of PCB. The core material is copper clad, and this will barely change the thickness of the manufacturing process of PCB. In a 2 layer PCB stack-up, the central substrate between the two copper layers is called the Top and Bottom layers. 

What are the Materials Used in a 2-Layer PCB?

PCB may use various materials as substrates. This materials selection for PCB depends on the application requirement. Some of the popular materials used in PCB fabrication are as follows:

• FR4 epoxy laminate and prepreg

It is one of the most commonly used PCB substrate materials. FR4 materials have proper electrical, thermal, and mechanical characteristics and suitable strength to make them ideal for various electronic applications. Usually, glass cloth and epoxy resin make the FR4 laminates, and they are one of the lowest-cost PCB materials available. FR4 has many additional advantages that make it suitable to use in PCB. It has the properties of good electrical insulation and excellent mechanical strength, which make it a good PCB material. 

• Polyimide laminates

This material offers a higher temperature compared to that FR4 materials. However, this polyimide material is expensive and also contributes to improving survivability in higher temperatures. They are more stable with fewer expansion characteristics, making them suitable for higher layer counts.

• Teflon

Teflon has good electrical properties; thus, you can use it for high-speed circuitry applications. They are more expensive compared to polyamide and offer high-speed capabilities. So, we can see less use of Teflon in 2 layer PCB stack-up only in desired application of high-speed circuitry. 

What Components are Used in a Typical 2-Layer PCB?

The components provide the purpose and work of the projects or the circuits. Components are the vital part of the PCB that makes the proper functioning of the board. 

PCBs have many components, but some of the most common types include

• Batteries
• LEDs
• Switches
• Resistors
• Capacitors
• Diodes
• Transistors

Battery

One of the most common components is the battery system. You can use it for proper voltage and current in the circuit. The battery will drive the entire working of the circuit board. The components, like LED, capacitors, switches, etc., will store the charge from the battery system.

Diodes

Diodes are another component used in PCBs that store charge and current. LEDs light up things, but simple diodes do not. In its place, diodes only pass on the current in one direction - the diode blocks the other direction.

Switches

The switch allows switching the current on and off in the circuit. Current can pass through the circuit when the switch is kept open. While if it is closed, the current can't pass through it.

Resistor

Resistors are one of the passive components used in the PCB that creates resistance for the current in the circuit. There are various reasons for the use of resistors. But one of the common reasons is the matching of the current in the circuit with the energy. With the use of the resistor, the current in one circuit can be matched to another, making the current flow easier between them.

Capacitor

It stores energy like the battery. It blocks the DC and allows the AC in the circuit. At the same time, an analog circuit smooths the output of the power. 

How do Arrange the Signal, Power, and Ground Planes on a 2-layer PCB Stackup?

Power Planes require proper design for heat dissipation. It is always a better idea to separate the high power of PCB, analog, and digital circuits to eliminate and reduce the change of adverse effects. The ground plane is required to absorb the circuit's noise and shorten the return path. 

The use of a ground plane helps in the proper routing of traces. You can minimize the EMI in 2-layer PCB by routing the return trace. You can place the signal trace close to the ground plane to suppress the crosstalk between the close traces. 

Through a vias, you can route ground returns directly from components to the ground plane when you place a ground plane below the relevant components and signal traces. The signal will follow the path with the least impedance to return to the power supply. This helps to place the bypass capacitor in between the power connection in the ground plane and critical components resulting in high-frequency fluctuation in reaching the relevant components. 

Factors that Determine the Designs of a 2-layer PCB Stackup

The PCB fabrication and assembly process is a more complex task and uses more advanced electronics for the circuit board. Designing the new circuit board prototype starts with a great PCB layout design or stack-up. Thus, one must consider all the design requirements and factors for a highly functioning board. 

• Vias Types

In other words, the vias connect the layers of the board. You will need different vias for different projects due to the different thicknesses of the boards. Some boards are one-sided, while others have 10 layers. A blind, through-the-hole, buried, or microsystem is available.

• Your trace thickness

The ounces of copper measure the track's thickness. Some PCB manufacturers can provide up to six ounces of thickness if needed; most PCB designers use one or two ounces of copper. Lamination and soldering problems can occur when the trace thickness is wrong.

• How will the PCB be stacked?

To figure out even the most basic details of your board, you must create a guide on how to stack your PCB. Based on how many levels there are in a PCB, you can determine the necessary raw materials and the time it will take to fabricate, which will determine the price.

• The design limitations

To ensure the board is according to your needs, you will need to establish rules for PCB fabrication. Your list should include component placement, layer distribution, and engineering time.

• Signal quality

It is essential to consider the impedances, track lengths, and signal rise and fall times. Test the pre and post-layouts to determine whether your outcome is effective or not.

Design Tips and Layout on 2-Layer PCB

PCB design rules are essential for developing high-speed PCBs. The proper PCB design rules can prevent unwanted costs and delays. The proper design rules help to generate the appropriate PCB board.

Some of the design tips of a 2-layer PCB are as follows:

• It must have sufficient space in between the traces. The close traces and pads could lead to a short circuit during manufacturing.
• Using the ground fills, balance the copper on each side.
• Reduce the EMI by using the closely-spaced, solid plane, the adjacent return path for the signal traces.
• Try to use a 45-degree trace angle and avoid using the 90-degree trace angle.
• Increase the width of the power and ground traces. You can reduce wire and board damage by making your power and ground traces wider, allowing more current flow.
• Form EMI shielding and heat-sinking power planes from solid copper layers.
• Power planes powered the PCB areas. The copper layers can be connected to power or ground to create power planes.
• On dense designs, consider burying the vias to utilize space above and below the vias for additional routing.
• Maintain proximity to a solid plane return path while establishing the shortest route with the fewest vias.
• Connect many test points across the PCB to the power and ground nets, facilitating board testing.
• Avoid placing the test points near the capacitors or any taller components. This makes the test points difficult.

What Determines the Price of a 2-layer PCB?

Various factors determine PCBs' price, including the assembling and manufacturing companies. Besides, some other factors determine the cost of the 2-layer PCB:

Manufacturing Material

The materials used in the PCB board directly affect the board's pricing. The standard PCB material is the FR4 material type. The material affects the chip's compatibility. At the same time, additional components are required that improve the reliability of the circuit. 

Some factors also determine the selection of the materials, which also affect the cost of the PCB. 

PCB Size

The panel utilization and the PCB size are factors that affect the price of the PCB. The board size determines the circuit numbers required for the devices.

The space consumed by the components on the PCB also affects the price of the board. Compared to a computer or laptop PCB, a PCB in a digital watch requires fewer components and is, therefore, less expensive to produce. In addition, most home electronics have smaller PCBs than large industrial machines.

Board prices will also depend on how much space is consumed by components. In certain cases, efficiency and production costs are less considered in the board's design.

One of the main factors determining the overall price of your PCB design is its dimensions. In some cases, manufacturing small PCBs at high volumes can result in lower total costs than manufacturing large PCBs at low volumes.

Board Thickness

For your PCB assembly, you can choose thick or thin boards. Compared to the latter, the former requires more materials and costs more. Additionally, the thickness of your PCB will increase the overall cost of assembly. It will require more resources.

A thick PCB will require a thicker lamination. Complex manufacturing processes also apply. In this case, you can expect a cost increase because of the thickness difference between 2-layer and 4-layer PCBs.

What is the Difference Between 2 layer and 4-Layer PCB?

The 4-layer PCB is advanced compared to 2 layer PCB. Thus, there are some pros and cons regarding these two PCB types. The 4-layer PCB is expensive compared to 2 layer PCB, but it can provide greater flexibility and working performance compared to the 2-layer PCB design. While on the other hand, the 4-layer PCB is a bit difficult to manufacture.

Pros of 2-layer PCB

• It is not expensive compared to 4-layer PCB
• The manufacturing process of a 2-layer PCB is easier.

Cons of PCB

• It has limited design flexibility
• It is less effective for high-speed and complex circuitry. 

Functionality 

The microstrip traces containing a ground plane have no propagation delays, so it has more functions in 2 layers PCB. In most cases, using a four-layer PCB design with two signal layers and two ground layers is more convenient. However, impedance and propagation delays are important to the design. 

Cost of 2-layer PCB and 4-layer PCB 

The complexity of design and higher sensitivity of 4 layers PCBs make them more expensive than 2 layers PCBs. There is also a factor that reduces distortion and propagation levels, which makes 4 layers of PCBs more expensive. With the increased signal integrity and reduced interference levels, more and more electronic engineering prefers 4-layer PCBs.

This 2-layer PCB is suitable for the cost-effective option and is one of the most widely used PCBs in the electronics domain. Also, 2, the layer PCB has no propagation delay with the signal. This time is no factor in this PCB design. While if you want a flexible design for the high-speed circuitry, you should go for the 4-layer PCB. 

How to choose 2 layers or 4 layers of PCB?

Many factors determine which PCB to use according to your requirement.

• Cost

Cost is the major factor determining which PCB to choose in your design since a 4-layer PCB is expensive compared to a 2-layer PCB. 

• Size

The size of the PCB also affects which layer to choose. Large boards typically require more circuit layers to reduce the possibility of signal crosstalk and other problems.

• Thermal Consideration

Thermal consideration also determines the layers of PCB to use in your project. If you want to dissipate heat quickly and effectively, a 4-layer PCB best suits you. 

• Signal Integrity

Signal integrity is a problem for the higher-layer PCB. Thus you need to consider this while designing PCB.

• Environment

The working environment of the PCB is the primary thing that requires the various layered PCB to operate. For example, the PCB with a higher layer is necessary for a high-temperature environment to prevent board warping.

Pros and Cons of 2-Layer PCB

With the increasing demand for circuit boards, many people prefer a 2 layer PCB design stack up. Some of the benefits of a 2-layer PCB design include:

• It has a shorter manufacturing time and a cost-effective design compared to other PCB types.
• It increases the routing space on both the layers of the PCB, including the top and bottom.
• It provides more design flexibility. At a low budget, you can increase the project numbers. Thus, you can have more excellent innovative projects, which are impossible with single-sided PCB. 
• 2 layer PCB can have a smaller design and is lightweight too.
• It offers increased reliability and durability compared to other PCB types.
• There is no propagation time in 2-layer PCB. Thus, it offers better signal integrity.
• It offers the best choice for sinking and sourcing the current. For sourcing in sinking currents, you can use the bottom layer of a 2-layer PCB as ground copper. 
• It has numerous applications in day-to-day life projects because of its reasonable price. 

Some of the drawbacks of this 2-layer PCB are as follows:

• 2-layer PCB is more prone to crosstalk and noise than other PCB types, thus, and is not durable.
• It is expensive to manufacture compared to single-sided PCB.
• The soldering process of through-hole vias is complicated.
• It has limited design flexibility and is difficult to perform for high design complete circuity.
• In comparison to single-sided PCB, 2-layer PCB has a lower yield rate.

Applications of the 2-Layer PCB

Double-Sided PCB provides a wide range of applications since it provides high versatility and circuit density. Some of the application of this 2-layer PCB includes:

• Power Circuits
• Control system/relays
• Industrial Automation
• Converters
• Instrumentation
• UPS systems
• HVAC
• Regulators
• Hard drives
• Printers
• Amplifiers
• Test Equipment
• Traffic systems
• Line Reactors
• Vending Machines

What is the Manufacturing Process of the 2 Layer, PCB Stack, up?

The manufacturing process of PCB goes through various steps. 

Step 1: Circuit and Layout Design

It is the very first step of any PCB manufacturing process. PCB design software is used for this purpose to make the schematic diagram of the circuit. After completing the PCB schematic design, you can start with the PCB layout design. 

Step 2: Material Selection

PCB manufacturers and users can choose from many different materials when making PCBs. Material includes a ceramic substrate, iron cores, an aluminum substrate, or an FR4 substrate with ceramic cores. PCB base substrates typically contain flame-retardant materials such as FR4. With FR4 board, PCB boards can remain stable and safe under extreme temperature conditions while remaining economical and affordable. 

While for high-speed and high-frequency applications, you need to use materials like the R04000 series, RT6000 series, etc.

Step 3: Copper Clad Laminate

The board is cut in the required shape and size. Various sizes are available. You need to cut the PCB board in a way that fits the machines. 

Step 4: Etching

The copper is etched to leave only the required traces and vias. Dry film and photo plotter complete this process. 

 Step 4: Drilling

The board then goes to the automatic drilling machine that makes the hole in the board. The mechanical hole, one of the simplest holes, is used to hold the board using the screw. After the drilling process, the board is cleaned, and think copper layer is applied, and finally, the board goes to the electroplating to increase the copper hole's thickness.

Step 5: Solder Mask

The next step in PCB making is applying the solder mask that protects the copper. It also prevents the solder from short circuits in between the traces. The solder mask is the thin insulating layer of the polymer in between the conducting lines. After drying the board, it undergoes the UV chamber that removes the excess of the solder mask. 

Step 6: Silkscreen

Applying silkscreen is the final step. It labels the PCB, marks the components, and places the logos on the board. There are various available silkscreens, but the standard color is white. 

2 Layer PCB Manufacturer - NextPCB

At NextPCB, we offer contract manufacturing services for PCBs. We also provide inspection and testing services and ensure every product is qualitative. We follow international standards and guidelines for our services. And we prioritize the timely delivery of our product without compromising the quality of our product. 

You can choose us for your 2-layer PCB or any other service. We provide you with the best quality work following all the required guidelines.  

Conclusion

PCB is an important part of any electronics domain and its use of it is increasing with the rise of advanced technologies. They provide the effective and best palace to communicate between the components and make a whole working system that could automate our requirements. The two-layer PCB is commonly used PCB among a large variety of boards because of its cost-effective nature. It is also popular because of its custom designs and high-temperature resistance. Thus, based on your requirement, you can select the 2-layer PCB for your project.