Tag Archives: PCB Fabrication

Physical and Electrical Partitioning In PCB Design

Physical and Electrical Partitioning In PCB Design

Partitioning your design into physical and electrical sections can significantly reduce the number of through-holes you need in your PCB, thereby increasing production speed and cutting down on manufacturing costs. Here, we will explain what physical and electrical partitioning are how they are used in PCB design, and how to create effective partitioning schemes in your PCB designs.
As you work on your next PCB design, you may be wondering how to implement physical and electrical partitioning in your design. These two factors are equally important to making the finished product successful, and both have a huge impact on the success of your design project as a whole. Stay with us if you’re looking to save time and money while producing high-quality products, read on!

Layout Considerations

When you’re laying out a Printed Circuit Board, you have two different considerations, such as physical, which is how your components are laid out on your printed circuit board; and electrical, which has to do with where you’re going to put all of your wires. These two can be grouped when it comes time for assembly.
For example, if you plan to use surface-mount parts that require soldering instead of wire-wrapping, then you will want to make sure that there is enough space between these parts so that they can be easily soldered onto your PCB. If you don’t leave enough space between them, then there won’t be room for solder paste. The solder paste is a sticky substance used to hold down SMT parts during pcb assembly.
This makes soldering difficult or impossible and the same logic applies to wiring. If you don’t leave enough space between components, then your wires may not fit without being bent too much or getting in each other’s way. This can cause problems when it comes time to solder everything together, as well as with heat dissipation, and too many wires crammed into one area might block airflow and cause overheating issues.
On top of that, you also need to consider things like trace width and spacing. Trace width refers to how wide your traces are (the lines connecting individual pads on your PCB), while trace spacing refers to how far apart they are from each other. Trace width should always be smaller than trace spacing because having wider traces means more copper is needed per unit length which means higher cost and greater weight.
Traces are usually made using either a single solid line or multiple lines connected by vias. Single solid lines tend to be faster but less reliable than multiple lines connected by vias, but they’re also easier to design and cheaper. Vias are holes drilled through layers of material that allow traces on different layers to connect.However, vias increase complexity and cost. There are several tools available to help designers create their circuits. Some free software options include EagleCAD, Kicad, Altium Designer, and CAD. However, regardless of what software you choose to use, remember that layout is only half of the process.

Physical and Electrical Partitioning In PCB Design-Content Image
Physical and Electrical Partitioning In PCB Design-Content Image

Overlapping Impedance Nets & Ghost Nets

To create a circuit board with electrical & physical separation, you must insert impedance nets into your design. There are three different ways you can do that, including overlapping impedances, creating ghosts, or through a virtual ground plane. In some designs, more than one method is used. So, let’s see how and when to use them.

An overlapping impedance net has part of it on one side of a barrier, and part of it on another side. A ghost net is used when you have two nets that need to be separated but you don’t want them physically separated because they are too close together or because they are too important for each other. A ghost net is just a virtual representation of an actual physical connection that exists between two parts of your circuit board.

A good example of why you might use a ghost PC board net instead of separating your nets with some physical method is if you have 2 power supplies that need to share ground. They can share ground by having their grounds tied together through some kind of wire.But, since they’re both supplying power independently, we don’t want them tied directly together at all times, but only when there is a current going through either one or both supplies. So what do we do? We create a ghost ground plane where we tie their grounds together. This way, when none ofthe supplies is active, there’s no connection between them, and when either supply is active, there isa connection between them.

An electrical partitioning net does exactly what it sounds like. It partitions electrical signals from each other. In a design where you want to physically separate your nets, you can do that by creating an impedance plane that separates them. But, then how do you keep them electrically isolated? That’s where a physical partitioning plane comes into play. This is just another name for a ghost ground plane, but instead of being used for sharing grounds between two supplies, it’s used for keeping two parts of your circuit board electrically isolated from each other while still allowing communication between them.

One last thing about these three methods is thatyou can’t use one without using at least one of the others. If you have a wall between two sections of your circuit board, there has to be some way for those sections to talk to each other. Otherwise, they wouldn’t be able to pass power or data. So, if you have a wall, you need ghosts or an impedance plane on both sides of it. And if you have ghosts, there needs to be a wall somewhere too.

Why Would You Ever Choose One Method Over Another?

Well, overlapping impedances are good when you don’t need high-frequency performance because they introduce more inductance than either of the other two methods. Ghosts are good when you don’t care as much about electromagnetic interference or EMI because they don’t create as much capacitance as either of the other two methods.

Whereas the physical partitioning nets are good when you want to keep your layout compact or if you have a design that’s already laid out and you can’t change it, as having a wall between two sections of your board is going to require some rework if it doesn’t already exist.
So, you need to decide if you want your partitions at a high frequency or low frequency. For a high-frequency circuit board, you’ll need to use overlapping impedances or ghosts; for a low-frequency circuit board, you can just go with physical partitioning nets.

Solving Unplanned Overlaps

It’s not uncommon for two different circuit boards or two different designs within a single board to overlap. Unplanned overlaps are hard to solve, but these tips will help you create better schematics so that you can avoid them.
Before you design your next PCB, make sure you follow all of these guidelines for PC Board Fabrication. By doing so, you’ll be able to identify overlaps before they occur and reduce your chances of creating any issues when manufacturing your product.
If you don’t have access to specialized tools or software, consider using some online tools like Google Sketch Up to help with your schematic design. These free programs allow you to build 3D models of your circuits, as well as export them into other applications like Eagle CAD or Altium Designer. This allows you to easily view how your components will fit together on a printed circuit board.
You should also use both software and hardware layout techniques to ensure that there aren’t any unplanned overlaps between your PCBs. While it may seem easier to just use one method, it’s important to understand how each technique works so that you can spot potential problems early on. For example, if you only use software-based layout techniques, then you might miss physical overlaps that would prevent a component from fitting onto your board.
Similarly, if you only rely on hardware-based methods, then you might overlook electrical conflicts that could lead to shorts or failures during testing. The best way to get around these kinds of issues is by using both types of layouts simultaneously. You can use a program like Altium Designer to lay out your circuit board, then print out an image of what you’ve created. Then take that printed image and place it over your actual PCB. This ensures that you catch any unplanned overlaps before they cause problems later on down the line.
Just remember, even though it takes more time upfront, double-checking everything twice is always worth it. With that said, there are still times when the overlap errors do slip through. When you find yourself in a situation where you need to resolve an issue like this, we recommend you double-check it. As it would become much easier to fix an error than it would be otherwise. You can also get professional help in this regard.
Would like to know more about physical and electrical partitioning in your designs or pcb assembly services? Write us at sales@pnconline.com

Tips for RF PCB Design

Tips for RF PCB Design

With so many things to consider when designing an RF PCB, it can be hard to know where to start. How do you choose the right layout? What tools should you use to get the job done? RF PCB design has its own set of challenges that need to be addressed to get the most out of your circuit. There are some best practices you can use to ensure that your design will function optimally and run smoothly.
The best PCB design solution can be the difference between success and failure for your product, so you want to make sure that you are getting it right the first time around. Our guide will walk you through all of the steps necessary to create an RF design that works and that makes your product even better than you envisioned.

Tips for RF PCB Design
Tips for RF PCB Design

Surface Mount Capacitors

Use surface mount capacitors when space is limited. You can incorporate them into your RF Printed Circuit Board design with no impact on performance. Try to keep track of how much space they’ll take and make sure there’s still enough room for other components on the board, like resistors and coils. The surface mount parts are more fragile than through-hole components and require an extra level of care when handling.
Consider using larger surface mount parts wherever possible, or incorporating test points into any sensitive areas if smaller parts are required. Remember that small surface-mount parts have very thin leads that could break off easily. Make sure you know what size of solder tip will be needed before moving forward with your design. If it’s too small, it could damage the delicate leads on these devices. It may also be difficult to attach them to boards after soldering as their leads are so small that they tend to slide around during assembly. When in doubt, use a slightly larger part.

Differential Pair Transformer Coupling

Choosing proper circuit components is an important part of designing and building circuits. When creating transmitter/receiver pairs, several factors influence how well each device will perform. The goal of any transmitter or receiver circuit is to accurately convert an input voltage into an output voltage with minimal noise and distortion.
These parameters are known as gain, linearity, bandwidth, noise figure, NF, return loss, RL, and intercept point, IP. A low NF results in more power being transferred from input to output. The IP value represents how much power can be handled by the front end of a given device before distorting or saturating it, all while maintaining its linearity characteristics.
In other words, if a device has high gain but poor linearity, then it may still have acceptable levels of IP. But if a device has high gain and poor linearity at lower power levels, then it won’t have good IP numbers. In general, devices with higher gains have lower bandwidths, however, there are exceptions to every rule. For example, some amplifiers have very high gains but also operate over wide frequency ranges.

Microstrip Transmission Lines

These are transmission lines in which all of their circuit elements, including those forming half-space planes, and terminations, such as capacitors and transformers, are fabricated on metal strip circuits. The strip circuit is usually etched onto an epoxy substrate using photo etching or electroplating techniques. The micro-strip designs have become very popular for many PC BOARD applications because they can be packaged in small cases with relative ease due to their thin profile. They also have good impedance matching properties over a wide frequency range.

Reference Planes, Power Planes & Ground Planes

Radio-frequency circuit boards or RF designs are often more sensitive to ground loops and signal integrity issues than regular designs because RF circuits and components are particularly susceptible to noise. One way that experienced designers combat these types of issues is by strategically adding power planes, reference planes, and ground planes to their board layouts.
Reference planes: The reference or signal planes can allow designers to focus on specific sections of a circuit without having to worry about interfering signals from other portions.
They also provide a convenient place for designers to add vias between layers of copper, which helps improve both signal quality and thermal performance. Reference planes can be especially useful when they’re directly connected to a component’s ground pin, which allows them to act as an extension of that component’s ground plane.
Power planes: they should always be connected directly to an external source of power, otherwise, they could cause voltage drops across adjacent traces and components.
Ground planes: They should always be connected directly to an external source of the earth, otherwise, they could cause the voltage rises across adjacent traces and components. It’s important to note that many high-speed applications use multiple ground planes at different potentials, so it may not be feasible to have just one global ground plane. However, it’s generally best practice to keep each section within a single board connected through at least one shared global ground plane.
By using separate grounds for different sections of a design, designers can avoid parasitic effects and increase the overall reliability by ensuring all parts of their designs have access to low impedance paths back to an external earth point.
In addition, it’s crucial to ensure that any ground or power planes are spaced far enough away from any active circuitry in order to minimize crosstalk. Generally speaking, there should be at least 1/10th of a millimeter between active circuitry and any nearby reference or power planes. The distance requirements become even more stringent with higher frequencies. When operating above 30 GHz, there should ideally be no less than 0.3 mm of separation between any ground or power plane and active circuitry.

Vias – Size, Shape & Placement

Vias are required in order for us to make electrical contact with traces on different layers. There are three types of vias, including plated through, blind, and buried. A plated through via connects one layer’s copper trace directly with another via’s copper trace or traces. A blind via creates electrical contact but no physical connection between two layers and a buried via provides both an electrical and physical connection.
Placement is generally determined by where it will be soldered or how many layers are involved. For example, if there are four or more layers involved then we recommend using plated through vias because they offer better conductivity than a blind via. If there are only two layers involved then we recommend using either type of visa, depending on its location relative to other components.
As far as shape goes, choose from square, round, or rectangular options that match your pcb fabrication layout requirements. Circular vias may also be available upon request, however, these have a higher cost associated with them due to their complexity and are not always necessary. We use wire-bondable vias wherever possible because they provide a faster assembly process. The above diagram illustrates each type of via along with its respective shape and size.

Isolating an RF trace

It is essential to isolate an RF trace from high-speed signals, including HDMI, USB differential pairs, or crystals’ clock traces. Experts do it through a method known as via stitching where vias are stitched around the RF traces to keep them away from other parts on the circuit board. But, there should be proper isolation as improper isolation can affect PCB function.

RF Circuit Board Insulation

Insulation is one of the most important factors for minimizing the signal loss in an RF transmission. If you want to ensure that your signal reaches its destination without any hiccups or interference, it’s crucial that you use good quality material for your board’s insulation, and choose one with at least 5-mil thickness.
One of our favorite options is Taconic TFEP as it offers superior heat resistance and can withstand temperatures as high as 350 degrees Celsius. It also has great mechanical properties and will last for years to come. Another great option is Rogers, which boasts similar properties but has a slightly higher temperature resistance.
You’ll also want to make sure that you’re using a good adhesive when attaching components to your board. This will ensure that everything stays intact even in tough conditions. If you want to ensure that your signal reaches its destination without any hiccups or interference, it’s crucial that you use a good, quality material for your board’s insulation.
You can create a flawless RF circuit board by considering all the above design guidelines.

Final Thoughts

RF PCB design has its own set of challenges that need to be addressed in order to get the most out of your circuit. There are some best practices you can use to ensure that your design will function optimally and run smoothly. You have to consider material, traces, surface mount capacitors, isolation, insulation, reference, ground, and power planes, vias size and shape, coupling, and micro-strip transmission line.
Would like to know more about RF design or pcb assembly services? Email us at sales@pnconline.com

Design Elements Influencing SMT Assembly

Design Elements Influencing SMT Assembly

Smart devices should perform well to satisfy consumers who want high-density devices. The Surface mount technology or SMT helps develop high-end electronics. The process of SMT involves soldering which goes through different problems due to PCB pads, reflow technology, stencil design, quality of the soldering paste, and different technical parameters.
SMT manufacturing involves many challenges and different design elements influence it. The supplier needs Gerber files and design data for the placement of components. Gerber files help configure different SMT manufacturing machines and develop stencils for placing the solder paste on the circuit board. The manufacturer and designer should discuss the design parameters and elements for precise SMT manufacturing.
So, different elements affect the quality of SMT that we will discuss below.

Making Bill of Materials (BOM)

SMT has various features and BOM is one of them. The flow of soldering has close contact with the bill of materials. You have to consider the below factors to create a high-quality SMT.
• Components packaging should be compatible with mounting requirements.
• The component figure should be according to the SMT requirements to get the desired shape with precise dimensions.
• The PC BOARD pad soldering should be compatible with the reflow technology to prevent its oxidation and the same applies to the solderable ends of the elements. If these two factors get polluted, it would result in defective solderings, such as solder beads or pseudo soldering. The same is true regarding the humidity sensor and PCB administration.

Design Elements Influencing SMT Assembly
Design Elements Influencing SMT Assembly

PCB Pad Design

PCB design highly influences the manufacturing of SMT in terms of quality. According to HP research, 80% of SMT manufacturing defects occur due to the poor design of a PCB. So, the designer should focus on essential factors, including the folder mask, layout of components, type of the substrate substance, thermal pad design, assembly techniques, component packages, the position of vias, optical positioning, and the transmission boundary.
If the PCB pad design is poor, it would result in deflected soldering even if the mounting position is fine. Like, tombstoning or disposition of components can happen. You can avoid these issues by considering the key aspects while designing the SMT pad, such as the distance between the pads, residual size of the pads, width and symmetry regarding pads, and avoiding through-hole vias.

Printing of Solder Paste

The paste of solder should have a compatible printing technology, or it will affect soldering. A poor printing of solder paste results in a deflected PCB that you have to revise. During the printing of solder paste, you should consider three essential elements, such as solder paste, scraper, and stencil

Quality of The Solder Paste

Solder paste is an integral part of reflow soldering, and it’s a combination of alloy and flux. Precise soldering joints depend on the powder of alloy, whereas the flux removes oxidation from the surface to ensure high-end soldering. Even, the paste of solder having 50 percent of solder of alloy can be enough if it has high quality. Two key factors of soldering paste, including storage and application, determine its quality. Make sure to store the solder paste at appropriate temperatures ranging from 0 to 10 degrees.

PCB Stencil

The pad of the PCB should have evenly applied solder paste through a stencil, which is a major factor in Printed Circuit Board printing. Moreover, the eminence of the stencil affects the printing eminence. The stencil is designed through different techniques, including laser cutting, and chemical corrosion. You can design stencils by considering certain characteristics, such as:
• The thickness of the steel sheet
• Aperture design
• Mark points
• Anti-solder ball processing
• Direction of printing
• Type of scraper in terms of shape and material

Printing Parameters

You have to consider essential parameters of printing for precise results, such as frequency, scraper speed, scraper pressure, stencils down release speed, and its cleaning mode.
Both pressure and speed of scraper should be well-balanced, like not so low or so high. If these values are not balanced, it would result in defective printing, thus influencing the manufacturing.

Right Equipment

There should be accurate equipment to have high-level printing of the soldering paste. A small space and high-density PCB should follow the right printing rules for a stable process.

Understanding PCB Support

The printing of the soldering paste depends on the PCB support, as its lack can result in an uneven soldering paste. So, it is important to have uniform PCB support to keep the PCB and stencil close enough.

Components Mounting

The mounting of the PCB parts or components depends on different elements, including the right pressure for mounting, the quality of the components, and their precise location. Components should be according to the BOM, and mounted on the PCB at the right place, following the right dimensions. At the same time, the mounter should be precise in this case to ensure a stable mounting of the components onto the PCB pads.
The mounting angle should be correct, besides, the mounting pressure should be suitable, like not too high or low. You can evaluate mounting through different elements, such as the thickness of the board, components’ package, mounted z-axis, and nozzle’s pressure.

Quality of Reflow Soldering

The temperature curves of the reflow soldering should be well-set to have high-quality soldering of areas to be welded. An increased temperature can affect the PCBA due to heat occurring at a fast rate. It would cause PCB deformation, damaging the components. Besides, the soldering paste has a solvent that gets volatile, splashing out the metal composites as tin’s plating balls. Engineers apply nitrogen reflow soldering to get rid of oxidation, enhancing the quality of soldering.
Moreover, make sure that the reflow soldering is compatible with the PCB substrate, size, material, weight, and thickness. Besides, it should be according to the reflow oven’s structure, and the temperature zone’s length should also be considered.
SMT assembly is easy to optimize by having the best PCB design and software to analyze it. The right design software helps you to set assembly standards without missing any factor.

Additional Information

The solder paste is applied to the pads through a machine by holding the stencil tightly on the PCB. Then components are placed according to the footprints with the help of optic technology. The engineers inspect the placement of the components through an optic machine to make sure it’s free from flaws, and this should be done before reflow soldering. Sometimes the x-ray technology is used for inspection which is essential before PCB testing. Such inspection helps detect poor solder joints, as well as short circuits that happen during the reflow soldering.
The placement machines are unable to hold a PCB if the PCB edge is crowded with components, and this can influence SMT manufacturing. You also have to consider the tooling strips for miniature PCBs. The tooling strips should be at least 6 mm to help a machine have a proper grip during the PCB assembly. You can also give the V-score on the tooling strips to separate the parts easily in the later stage.
Keeping the SMT components in one direction can also reduce the flaws and helps have placement the components in one go. So, the selection of the components and their placement affects the SMT assembly, making it smooth or horrible.

Frequently Asked Questions

What is PCB?
PCB is an abbreviation of Printed Circuit Board. It is used in electrical devices to provide them with signals or currents to operate. Printed circuit boards are used in different industries, including networking, electronics industry, gadgets, aerospace, and much more.

What is SMT in PCB?

SMT stands for Surface mount technology, and it helps develop high-end electrical devices.

What is Soldering in PCB?
Soldering is a manufacturing technique in PCB where two metals are connected through another material’s fusion. It should be precise because poor soldering results in a device malfunction.

What Are Important Characteristics Of A Stencil Design In PCB?
Stencil design depends on certain characteristics, such as the thickness of the steel sheet, aperture design, mark points, anti-solder ball processing, the direction of printing, and the type of the scraper in terms of shape and material.

Final Thoughts

Smart devices should perform well to satisfy consumers who want high-density devices. The Surface mount technology or SMT helps develop high-end electronics. The process of SMT involves soldering which goes through different problems due to PCB pads, reflow technology, stencil design, quality of the soldering paste, and different technical parameters.
SMT manufacturing involves many challenges and different design elements influence it. PCB design highly influences the manufacturing of SMT in terms of quality. According to HP research, 80% of SMT manufacturing defects occur due to the poor design of a PCB.
The PCB designer should focus on essential factors, including the folder mask, layout of components, type of the substrate substance, thermal pad design, assembly techniques, component packages, and the position of vias, optical positioning, and the transmission boundary.
Like to know more about the Design Elements or PC Board Fabrication? Write us at sales@pnconline.com

Significance of Copper Coating in PCB Design

Significance of Copper Coating in PCB Design

Printed circuit boards have a certain unused area, which is coated with copper known as copper coating or filling. There are several benefits of copper coating and one of them is to minimize the impedance of ground wire, as well as enhance the anti-interference and power supply, and minimize the voltage droppings.
The copper coating also helps prevent the deformation of a PCB during soldering. However, you have to manage copper coating properly to avoid certain issues that we will discuss here and find ways to resolve.

PCB has wirings distributed capacitance regarding high frequencies. The designer knows that when the length is higher than 1/20 of the corresponding wavelength of the noise frequency, it will cause the antenna effect causing the noise emission through wiring. Poor grounding of copper results in noise, so the ground line should have a hole with a pitch that is lower than λ/20 to have a good grounding on a multi-layered Printed Circuit Board.

The grid has traces in multiple directions and the trace width comes up with a corresponding electrical length to help a PCB operate. If the operating frequency is low, the gridline becomes less effective. But, the electrical length compatible with a PCB’s operating frequency causes bad effects and the PCB stops working transmitting the signals somewhere else.

High-frequency PCB resists a multi-purpose grid having high-interference requirements. On the other hand, the low-frequency PCB comes up with a wide current circuit and the designers use it for copper plating.
The grid should be compatible with the PC design, otherwise, the signals get scattered interfering with the entire system. The high-frequency PCB should have a high multi-purpose grid, and low-frequency PCB involves copper laying.

There are two methods of copper coating known as grid copper and large-area coating. In a large-area copper coating, bubbles develop due to wave soldering. In large-area coating, some slots are opened and the foaming of the copper foil is alleviated. Whereas the grid coating provides shielding to reduce heat dissipation, and it also provides electromagnetic shielding.

  • Sometimes the PCB has several grounds, including GND, AGND, and SGND. The main surface of a circuit board becomes a reference to use copper plating, or as a digital or analog ground. However, copper pouring does not need to be separated. Moreover, the designer has to increase the thickness of the power connections, such as 3.3V and 5.0V which helps make different deformed surfaces having different shapes.
  • When it is about different grounds single-point connection, the process involves a connection through magnetic beads or 0-ohm resistors.
  • You also have to take care of copper coating in areas adjacent to the crystal oscillator, which is a source of high-frequency emission. The basic technique is to shield a copper coating of the crystal oscillator and ground it separately.
  • There is another issue of a dead zone, also known as the Island. However, you can reduce it by defining a hole.
  • PCB ground should have equal treatment while wiring. You can’t depend on copper coating by adding a hole to remove a pin’s connection, as it would affect the signals badly.
  • The PCB design should not have sharp angles, such as 180 degrees, because they cause a transmitting effect in terms of electromagnetism.
  • The multi-layered PCB’s middle layer has open wiring that should not have copper as it is harder to manage and keep it grounded.
  • You should also properly ground the metal reinforcement and a metal heat sink.
  • You should also properly ground the metal block that causes heat dissipation regarding a three-terminal regulator. The isolation belt of the crystal oscillator should also be grounded properly.

So, you can make a copper coating significant by managing the grounding issues. Such management can reduce the signal path’s backflow issue and also reduce electromagnetic interference.

Many unused surfaces in a PCB are coated with copper known as copper coating or filling. There are several benefits of copper coating and one of them is to minimize the impedance of ground wire, as well as enhance the anti-interference and power supply, and minimize the voltage droppings.

The copper coating also helps prevent the deformation of a PCB during soldering. However, you have to manage copper coating properly to avoid certain issues that we will discuss here and find ways to resolve. PCB has wirings distributed capacitance regarding high frequencies. The designer knows that when the length is higher than 1/20 of the corresponding wavelength of the noise frequency, it will cause the antenna effect causing the noise emission through wiring. Poor grounding of copper results in noise, so the ground line should have a hole with a pitch that is lower than λ/20 to have a good grounding on a multi-layered PCB.

Moreover, the grid has traces in multiple directions and the trace width comes up with a corresponding electrical length to help a PCB operate. If the operating frequency is low, the gridline becomes less effective. But, the electrical length compatible with a PCB’s operating frequency causes bad effects and the PCB stops working transmitting the signals somewhere else.

As you know that high-frequency PCB resists a multi-purpose grid having high-interference requirements. On the other hand, the low-frequency PCB comes up with a wide current circuit and the designers use it for copper plating. The grid should be compatible with the PC design, otherwise, the signals get scattered interfering with the entire system. The high-frequency PC Board should have a high multi-purpose grid, and low-frequency PCB involves copper laying.
There are two methods of copper coating known as grid copper and large-area coating. In a large-area copper coating, bubbles develop due to wave soldering. In large-area coating, some slots are opened and the foaming of the copper foil is alleviated. Whereas the grid coating provides shielding to reduce heat dissipation, and it also provides electromagnetic shielding.

Significance of Copper Coating in PCB Design
Copper Coating in PCB Design

Also, PCB has several grounds, including GND, AGND, and SGND. The main surface of a circuit board becomes a reference to use copper plating, or as a digital or analog ground. However, copper pouring does not need to be separated. Moreover, the designer has to increase the thickness of the power connections, such as 3.3V and 5.0V which helps make different deformed surfaces having different shapes. When it is about different grounds single-point connection, the process involves a connection through magnetic beads or 0-ohm resistors.
Similarly, you must take care of copper coating in areas adjacent to the crystal oscillator, which is a source of high-frequency emission. The basic technique is to shield a copper coating of the crystal oscillator and ground it separately. There is another issue of a dead zone, also known as the Island. However, you can reduce it by defining a hole.

Moreover, the PCB ground should have equal treatment while wiring. You can’t depend on copper coating by adding a hole to remove a pin’s connection, as it would affect the signals badly. The PCB design should not have sharp angles, such as 180 degrees, because they cause a transmitting effect in terms of electromagnetism.
The multi-layered PCB’s middle layer has open wiring that should not have copper as it is harder to manage and keep it grounded. You should also properly ground the metal reinforcement and a metal heat sink. You should also properly ground the metal block that causes heat dissipation regarding a three-terminal regulator. The isolation belt of the crystal oscillator should also be grounded properly.

You can make PCB more effective by applying copper plating the right way. The design of the PCB matters a lot in this case because you need the right tools. Lots of software are there that designers use according to their requirements. You can also get customized PCBs through online platforms by giving your requirements.

At the same time, you need to follow specific design rules, and the fabrication should also be of high quality. Both designer and manufacturer should be experienced to provide the best PCB with correct copper coatings.

Wrap Up

PCB has wirings distributed capacitance regarding high frequencies. The designer knows that when the length is higher than 1/20 of the corresponding wavelength of the noise frequency, it will cause the antenna effect causing the noise emission through wiring. Poor grounding of copper results in noise, so the ground line should have a hole with a pitch that is lower than λ/20 to have a good grounding on a multi-layered PCB. The grid has traces in multiple directions and the trace width comes up with a corresponding electrical length to help a PCB operate. If the operating frequency is low, the gridline becomes less effective. But, the electrical length compatible with a PCB’s operating frequency causes bad effects and the PCB stops working transmitting the signals somewhere else.

High-frequency PCB resists a multi-purpose grid having high-interference requirements. On the other hand, the low-frequency PCB comes up with a wide current circuit and the designers use it for copper plating. The grid should be compatible with the PC design, otherwise, the signals get scattered interfering with the entire system. The high-frequency PCB should have a high multi-purpose grid, and low-frequency PCB involves copper laying.

Would like to know more about the Copper coating in PC design or pcb fabrication? Write us at sales@pnconline.com

What is High TG In PC Board Fabrication?

The making of PCB involves different steps, technologies, and terms, and TG is one such term that refers to the Glass Transition Temperature. High TG PCB is the board made at a high temperature. We will discuss this topic in detail, including the TG value, features, applications, materials, parameters, and much more.

What is High TG PCB?

If a PCB’s temperature goes beyond a set TG value, its condition will change. Like, the solid board will turn rubbery, affecting a PCB’s function. Depending on where you use a PCB, the temperature of the application should be at least 10 to 20C less than the PCB temperature.

Understanding TG Value

TG means Glass Transition Temperature like there is a certain limit of this temperature for PCB and that specific temperature is the TG value. TG value helps in understanding the PCB material, and you can find which temperature is required for its service.

Secondly, it helps you to find the condition of the PCB material, like if it’s solid, flexible, or solid-flex.

High TG PCB and Its Features

You have to choose a high TG Printed Circuit Board for your application carefully, because it involves multiple features, including thermal, electrical, mechanical, and chemical features.

Thermal Features: they include the TG or Glass Transition Temperature, thermal conductivity, thermal temperature’s coefficient, and decomposition temperature. TG is the temperature at which the state of the PCB material changes. But, when the board cools down, it gets back to its initial condition.

Electrical Features: they include the surface resistance, electrical power, volume relativity, and the dielectric constant and loss tangent.

Chemical Features: the chemical properties of a high TG PCB include the moisture absorption and the methylene chloride resistance of the PCB material. The TG PCB should be able to resist moisture if it’s near water.
Mechanical Features: the mechanical features are also important to know regarding the TG PCB. They include the flexural and peel strength, and the young’s module.

Suitable Materials for High TG PCB

A PCB has two materials, including laminate and substrate. The substrate includes epoxy resin, glass, or paper weave. The substrate should be compatible with the TG. Some common substrates that we use for a high TG PCB are;

  • CEM-1, 2, 3,4, and CEM-5
  • G-10 and 11, FR-1 to FR-6
  • Aluminum
  • Knapton
  • Pyralux

The last three materials are flexible.

The laminates should also be compatible with your TG PCB in terms of strength and temperature. Some common laminates are:

  • FR-1, and FR-4
  • CEM-1, CCEM-3
  • Teflon

Criteria for High TG PCBs

Printed circuit boards with a high TG value are based on certain criteria as described below:

  • The selection of a PCB, depending on the components like it can be single or double-sided PCB or embedded.
  • The stack-up PCB with a single layer or several layers
  • The design of such boards can be based on a module or it can be custom
  • The strength of the board also matters, like it should be robust either electrically or mechanically
  • PCB’s bendability also helps to classify the TG PCB, like if it’s hard, flexible, or hard-flexible
  • The electrical strength also helps classify the TG PC Board

Generally, manufacturers use bendability and strength to classify a TG PCB‘s physical properties.

Where Can You Use The High TG PCBs?

You can use the high TG circuit boards in intense conditions, as the environments with high-vibration devices. They are also suitable for applications with shocks, chemical components, and high temperatures. Like, missiles and car parts often come up with chemicals. So, the suitable industries for high TG PCBs include aerospace, telecommunications, military and defense force, automobile, and down-hole drilling.

What to Consider While Designing a Rigid PCB?

You must hire a professional PCB manufacturer for the right design, manufacturing, and assembly of these boards. The engineer must know the kind of environment that suits a TG PCB to function precisely. Below are a few examples to help you understand it.

Commercial Use

Many telecommunication companies use the best materials for mobile devices to enable them to bear high shocks. Like, the phone should not get damaged easily when you drop it.

Auto Industry

PCB has to be safe under a car’s hood as it’s mostly vibrating, so a shock or crash might happen. Hence, a rigid PCB is the best solution in this case.

Aerospace Industry

The flying machinery always needs the high TG PCB because there is intense vibration, like in the jet engine, as there are thousands and millions of micro-vibrations in one minute. So, equipment related to aerospace should be able to tolerate extreme temperatures, like from -45°C to 85°C.

Other Applications

These boards are also ideal for solar power equipment, such as power inverters and cogeneration equipment. As these boards resist temperature, they work well in many industries. Like, one of its applications involves Lead technology, like the medical, computer, and telecommunication industries.

The TG PCB is also used in broadcasting, like booster stations. Besides, the fire detectors and burglar alarms also need such boards.

Use of High TG Flex PCB

It is clear from the name that a flex PCB can adapt any design or shape to get compatible with certain products. Like, they can tolerate intense environments better than rigid PCBs. You can use the high TG flex PCB in defense and military, aerospace, medical equipment, consumer electronics, auto, wireless networks, as well as industrial equipment.

What To Consider While Designing a Flex PCB?

You must hire a professional PCB manufacturer for the right design, manufacturing, and assembly of flex PCB. The engineer must know the kind of environment that suits a TG PCB to function precisely. You should see if:

  • You need a flex PCB for an ordinary environment or an extreme environment like an explosion. Whereas the cell phone has a normal environment.
  • The environment should be free from any moisture before installing a high TG circuit board.
The Design Process

The design of a high TG PCB involves different steps, such as

  • Using the right software, like CAD, Eagle, Altium Designer, etc.
  • You must know the power requirements to suit different components on the PCB. You should also consider a specific plan for noise reduction caused by a TG PCB.
  • Preparation of the stack-up plans documents as it is essential for making the best TG PCB.
  • The floor layout for a PCB with proper sections, including components. Like you can place them together or separately.
  • TG PCB should be complete in terms of a power plane and ground details. These details ensure proper routing for signals.
  • The board should be compatible with patterns in terms of sizes. All components should be well-placed to help a PCB function the right way.
  • It is important to design routs for high-frequency signals, as the route should be clear for a flawless signal transfer. This step involves vias, as they help in proper signals. You need the reverse via and signal via in this case.
  • You must follow the 3W-rule to increase the traces’ distance which helps to reduce the coupling effect.
  • Another rule to reduce the coupling effect is the 20 H rule.
  • In the end, check the routing guidelines to see if you are doing everything the right way.
Specs and Design Parameters

The fabrication of a high TG PC Board Fabrication involves certain parameters and specs, depending on the application. Some standard parameters are described below.

How Many Layers Do You Need

Designers prefer the even number of layers while developing the high TG PCBs. But, the odd numbers of layers are also suitable in certain applications.

Dimensions of PCB

The PCB dimensions depend on its application. Like, you need a large circuit board for a broader application. Besides, there should be enough space on the board to place the electrical components.

Well-Finished

The high TG PCB should be well-finished, and the material depends on where you want to use this board. Like, some common materials are;
HASL, or hot air leveling – It is ideal as it is cheap and can be stored for longer.
OSP, or organic protective surface
Immersion silver – It gives a smooth surface, and it is cost-effective. It has many storage limitations
Immersion tin – It suits the SMT

Immersion gold – It can be stored for longer with a few limitations.

ENEPIG, nickel palladium – It can be stored longer, but it involves a complex process.

Solder mask – It protects the PCB from environmental elements.

Weight of copper – You must also consider the weight of copper like it includes both initial and finishing copper. Generally, the weight is 1 oz. to 1.5 oz. or 5 oz. It also depends on the layer and board thickness.

Assembled PCB thickness – The TG PCB thickness depends on its material and type. Like, if it’s flexible, hard, or a hard-flex board.

Distance between layers – The distance or spacing of electrical components and layers should be equal for high-frequency signals. As it reduces the coupling effect.

Via sizes – The drill aspect ratio and the hole size should also be appropriate. Generally, the PG PCB can have either plated-through or non-plated through holes, depending on the placement and layout design.

Board quality – The board should have a high-grade material to ensure an effective function during application. Besides, you must check the quality of the TG PCB to evaluate its performance in terms of specs. Like, you should test its lamination, vias, copper plating, solderability, finishing, components, and cleanliness.

Interested to know more about PCB TG or PCB Assembly? Email us at sales@pnconline.com