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Flexible Circuit PCB Assembly

Flexible Circuit PCB Assembly

It can be tricky to figure out what you need to know about flexible circuits assembly, especially since it’s not something many people are familiar with or have experience with. Flexible electronic assembly is one of the most innovative and useful circuit boards in the electronics world since it allows you to make low-profile electronic devices with multiple electronic components.
The Circuit board has different types, including a standard or rigid PCB, a flex PCB, and a flex-rigid PCB. Besides, these circuit boards are further divided into single-layer PCBs, double-layer PCBs, and multilayer PCBs.
A flexible circuit board has a flexible base, but the components are just like a rigid circuit board. However, you can turn a flex PCB into any shape while using it which means it is easy to bend.The following article will help you learn everything you need to know about flexible smt assembly so that you can get started working on your designs right away.
Before we move to the assembly of a flex PCB, we want to discuss its applications.

FPCB Applications

The FPCB is a vital part of electronic products that we use daily, such as desktop printers, hard disks, and several other devices. You would see the use of a flex circuit board in the below industries.

  • Medical industry
  • Consumer electronics
  • Communications industry
  • Military
  • Automotive industry
  • Aerospace industry
  • Transportation

Engineers use it in the transportation industry because flex PCBs are vibration-resistant and constant movement for several hours can’t damage them.

Choosing The Right Material And Processes

When it comes to choosing the right materials and processes for your flexible circuit board assembly, there are a few things you need to keep in mind.
First, consider the environment in which the board will be used. Will it be exposed to harsh chemicals or extreme temperatures?
Second, think about the amount of flexibility you need. The more flexible the circuit, the more expensive it will be. Finally, consider the size and weight of the finished product.

What Are The Uses Of The Flex PCBs?

Every kind of circuit board has specific uses because it is an important part of different products, especially electronics. Designers preferflexible circuit boards for computers, mobile phones, and servers to make them more effective, less heavy, and more flexible. Though different devices have different shapes, functions, and sizes, they all include flexible circuit boards.
Let’s look at the main uses of flexible Printed Circuit Board
1-FPCB is Flexible

  • The flex circuit board is an elastic board that helps in placing it near folds or edges.
  • It is suitable for 3-axis connections due to its elasticity.
  • FPCB involves minimum wiring, whereas some applications don’t require any wiring at all. So, there are no wiring issues that make a device more reliable.

2-Flex PCB Reduces Weight and Space
Unlike rigid circuit boards, a flex PCB needs less space. According to engineers, it can save 60 percent of space, hence, its weight also decreases.
3-Flex PCB Reduces Connectors
If you use a flex PCB in a 3D design, it will eliminate or reduce connectors. Whereas the bending cycles go up to 200 000.
4-FPCB Eliminates Vibration
A flex PCB is very light which helps it absorb movements or vibrations. So, the vibrations can’t damage an FPCB. Moreover, the solder joints also stay safe.
5-Compatible With Tough Environments
You can use a flex circuit board in tougher environments due to its material. Its main materials are water-resistant, shock-resistant, heat-resistant, as well as corrosion, and oil-proof.
6-Thin layers
Flex PCB has thin layers on the inside which reduce its weight. The copper layers in an FPCB are heavy which if combined with thin layers becomes useful for high-power applications.

Types of Flex Circuit Board

A flex PC Board has different types, including single-sided, double-sided, multilayer flex, and rigid-flex circuit boards. Let’s look at their pros one by one.
Single-sided F PCB: It is economical, flexible, and has many bending cycles.
Double-sided F PCB: Its design is more flexible than others. Moreover, it saves space and provides dual-sided soldering.
Multilayer F PCB: It is lightweight and compact and its flexibility is more in a 3D design. It is compatible with blind and buried vias.
Rigid-flex circuit board: It helps have a long-lasting 3D application having stable parts, pins, heat streaks, etc. It reduces noise and enhances signal integrity.Besides, it is more reliable and offers better impedance.
It helps have minimum mechanical space and reduces the weight of the device. It is compatible with the HDI micro-via. It is economical and offers a flexible pcb design.
Some More Advantages
A flex PCB can give you many benefits, but mainly it enhances flexibility and saves space. Its assembly involves a few items that reduce its cost and manufacturing time.

  • A flex circuit board offers a high-heat dissipation.
  • It enhances the inner airflow.
  • It reduces the size and weight of the package.
  • It involves minimum assembly errors.
  • It reduces the inductance of wires.
  • A flex circuit board enhances the product’s looks.
  • The assembly time and cost of the FPCB are less in some cases.
Flexible Circuit PCB Assembly
Flexible Circuit PCB Assembly

Flexible Printed Circuit Board Assembly

The assembly of a flex PCB is the same as a rigid board except for a few changes due to certain technical needs. The assembly of a single-layer flex PCB consists of the following steps

  • BOM
  • Electrical testing
  • Punching process
  • FPCB baking process
  • Optical inspection
  • FQC process
  • Silkscreen printing process
  • Reflow soldering
  • Packaging process
  • Mounting process
  • Deep inspection

Flex To Rigid Surface
Since flex PCB is soft and gets deformed, it is hard to assemble it directly on SMT. So, engineers fix it on a hard surface such as a tray for the assembly process. The tray or a hard carrier should be well-intact to make assembly smooth.
Low-Density Assembly
Flex PCBs aremore costly than the rigid circuit board, so most of them are used for connecting different modules having different functions. So, the FPCB assembly involves fewer components in the case of low-density assembly. The quantity of the components ranges from 2 to 50 in this case.
Increased Panels
Manufacturers use many planes during FPCB assembly to enhance the process. A flexible circuit board is used in smart products, such as digital cameras and mobile phones, so a single board is too small. As it involves a few components, manufacturers use panels which are then removed through punching.
Use of Auxiliary Fixtures
Flexible PCB assembly involves auxiliary fixtures as it deforms easily. These fixtures include:

  • Baking fixture
  • Carrying tray for FPCB
  • Electrical and function test fixtures
  • Cutting Fixtures

High Demand for Quality
The devices with FPCB are used in an environment where the accuracy of control has to be high. So, the board components should be well-positioned to get compatible with a particular environment.One must focus on certain factors, such as anti-static precautions, cleanliness, and reliable soldering. It also involves several technical issues.
Increased Assembly Cost
A flex circuit board has a costly assembly compared to a rigid circuit board. It involves many fixtures which also increases its cost.Theassembly process takes more time than a rigid PCB. Moreover, the assembly involves lots of accessories and working labor because less equipment is used. Besides, the increased demand for high quality and flawless manufacturing environment also is the reason for the high cost.
However, as the flex circuit board’s application is increasing, so new technology and assembly methods emerge. Eventually, the assembly cost decreases due to less time and tools involved.
Choosing A Supplier
When it comes to choosing a supplier for your flexible circuits PCB assembly, there are a few things you need to take into account. First, you need to make sure that the supplier is reputable and has a good track record.
Second, you need to make sure that they have the necessary experience and expertise.
Third, you should ensure that they are able to meet your specific needs and requirements.
Fourth, you should see if they are able to provide you with a competitive price. Finally, you need to ensure that they can produce high-quality products at an efficient rate.
For example, some of the key considerations when selecting a supplier are quality control measures in place and their ability to adapt to changes in demand. To put this another way, if a company’s success relies on being able to keep up with production rates, it will be easier for them to fulfill orders if they’re accustomed to adjusting according to supply and demand than if they’re not. The same thing goes for quality control, as companies without established procedures may not be as adept at preventing defective products from reaching customers.

Final Words

Flexible circuits are used in a variety of products, from hearing aids to sports-related items like fitness trackers and smartwatches. They allow you to connect electronics into your home, and even onto your body, giving you easy access to valuable data and features. However, with all this flexibility comes the need for greater care in assembly than typical PCBs require. The designer must know about flexible circuits and PCB assembly to ensure the end product works correctly and lasts as long as possible.
Would like to know more about Flexible Circuit assembly or pcb assembly services? Email us at sales@pnconline.com

How To Design A Signal Amplification PC Board

How To Design A Signal Amplification PC Board

Various kinds of circuit boards are essential for electronic devicesand the amplifier PCB is one of them. You need amplifiers to reproduce sounds, so the amplifier circuit board is vital for sound-generating devices, such as loudspeakers.

Understanding An Amplifier PCB

A PCB with an amplifier produces enhanced signals that input terminals require. Such a circuit board consists of electronic components to transfer signals. The components also increase the power of the amplifier by transferring signals through specific transistors. A substrate is an essential part of an amplifier circuit board like it’s a surface with components and it is composed of resin and fiberglass.

Though the amplifier is an independent component, it has several parts in it. An amplifier circuit board has many resistors and capacitors to perform various functions. Moreover, it has input and output terminals for both original and amplified signals.

Such a PCB can be small or large, depending on the device and its application. Generally, the headphones amplifiers are small, whereas the professional sound system has a large amplifier that singers and musicians often use. The size of a large amplifier Printed Circuit Board goes beyond 100 square inches.

The small amplifiers often depend on an external source for power supply whereas the battery-driven amplifiers are different.  Such PCBs are either power amplifiers or audio amplifiers.

How To Differentiate The Normal And Amplifier PCB

A normal PCB uses through-hole technology that helps drill holes and install PCB components. Surface mount technology is also another way of constructing a normal PCB.

On the other hand, the construction of an amplifier circuit board involves a schematic design. Certain design software helps place the components, whereasthe nature of the board determines its physical properties.

You need to consider the thermal and geometry factors while placing the components in an amplifier PCB. Likewise, in such a PCB, the power input and output work with respect to transistors’ resistance.

The amplifier circuit board has a better dielectric constant than a normal circuit board. But, the design of both kinds of PCBs needs a schematic diagram. You can also design a normal PCB manually like through Photomask.

How To Design A Signal Amplification PC Board
How To Design A Signal Amplification PC Board

What Are Heat Sinks In Amplifier PCB design?

There are heat sinks in the amplifier circuit boards which dissipate the heat caused during a PCB function. Engineers use aluminum to make heat sinks because it is highly conducive compared to other materials. Besides, aluminum resists corrosion and abrasion better than other metals.

The function of the heat sinks depends on two elements, including copper coins and thermovia.You need specific components to mount the heat sinks on the amplifier circuit board.Moreover, you also need solder pins and lock tabs during mounting. Heat sinks help a circuit board to manage its thermal propertywhich is the key element of the board.

Applications of Amplifier PCB

There are many applications of amplifier PCBs but their main function is to transform analog signals into digital ones.So, the amplification of the signals is the main thing in this case. Let’s see its applications one by one.

The amplifier PCB increases the amplitude signals, maintaining the frequency and several other elements.
This kind of PCB is able to transfer analog signals to square waves through the input saturation of a much high level.
The output resistance and voltage are also high in an amplifier PCB which helps it to produce enough output for the loudspeakers’ function.
It helps figure out the metal fatigue, ultrasonic cleaning, and ultrasound scanning.
The amplifier circuit board having a constant increase in the DC and AC is ideal for oscilloscope.
However, it has a low input resistance, and it works as a barrier between the circuitry and the receiver.Besides, it eliminates the signals it does not need.

Main Elements of An Amplifier Circuit Board

The board has certain characteristics as described below:

High Input Impedance: The high-input impedance is essential because it causes the voltage drop only on an amplifier, which is not possible in the low-input impedance. So, the amplifier PCBs need materials with a low-input impedance. You can eliminate the loading through a high-input impedance. The amplifier absorbs more current if its input impedance is low.

Enough Bandwidth: The bandwidth should be well-balanced in an amplifier circuit board to get compatible with the frequency being amplified. There will be no signal frequency if the bandwidth is narrow. Likewise, the wider bandwidth causes a lot of noise, so the bandwidth has to be undercontrol.

Increased Open Loop Signals: The amplifier increases signals’ power that you can evaluate between the input and output channels when the circuit board gets no feedback. The board might get feedback when the open-loop gains are high.

Stability of An Amplifier

You have to consider the amplifier’s stability while designing it. Signal distortions often happen when the amplifier is not stable. Many instabilities happen in the function of an amplifier PCB which can be controlled by considering certain factors while making its layout. By considering these factors, you can eliminate the board- spin failure, power strength, and signal integrity issues during its function.

The amplifier gets unstable if there are changes in the input signals. Some common issues with the amplifier stability are as below.

Ringing issues

In this case, the output can create a damped oscillation, reaching a stable output. It might involve undershooting and overshooting the output.

Oscillation Issues

It happens because of the load input and the impedance of the amplifier output. Such an issue affects the transfer ability of the amplifier by creating a pole.

Various Parasitic Feedbacks

It involves parasitic coupling which causes negative or positive feedback to the input terminal. This is a very unstable behavior of an amplifier that you can identify through an on-amp circuit.

Why Is Amplifier Stability Important?

When it comes to the RF systems, the amplifier stability becomes evident, like in telecom systems that involve the RF frequencies. Such systems useRF power amplifiers having high-signal power and frequencies, so you have to be careful while placing them in the signal chain.

When the layout has errors due to unnecessary parasitics, the output signals would become unstable. So, you must test the RF power to check the unstable behavior of the amplifier circuit board. Such management ensures that the RF system will function correctly.

Types of Amplifier PCBs

The amplifier PCBs have different categories, depending on their nature. In general, the number of power and audio amplifier circuit board designs is above 108. Engineers also classify them as A, B,C, and going up to G.

Group AAmplifier

You will see the gain and high linearity in this amplifier PCB layout. Besides, it has a 360-degree conduction angle. It remains functional during the entire signal’s input. Moreover, it includes an always-ON transistor.

Group B Amplifier

It involves two active devices and users can bias the amplifiers step-wise during the positive and negative cycles of the signals.

Group AB Amplifier

You can have the AB amplifier to eliminate the cross-over distortion of the signals.

Group C Amplifier

It is also known as a tuned amplifier that works through two modes, such as turned and unturned mode. Such a layout’s conduction angle is lower than 180 degrees and it is 60 to 70 percent effective.

Group D Amplifier

Such a layout involves the Pulse Width that changes its input signals.However, there is no role of conduction angle in this case. Besides, it does not need a linear gain.

Group E Amplifier

It is the most effective power amplifier that involves switching topology and radio frequencies as well.

Group F Amplifier

Such an amplifier comes up with high impedance like in harmonics. It includes the square and sine waves.

Group G Amplifier

It enhances a circuit board’s function using less power. Such amplifiers depend on the systems known as rail switching.

FAQs

What Is An Amplifier Circuit Board?

The construction of an amplifier circuit board involves a schematic design. You need to consider the thermal and geometry factors while placing the components in an amplifier PCB. Besides, the power input and output work with respect to transistors’ resistance.

What Is A Normal PCB?

A normal PCB uses through-hole technology that helps drill holes and install PCB components. Whereas surface mount technology is also another way of constructing a normal PCB.

What Are Heat Sinks In An Amplifier PCB?

Heat sinks in an amplifier PCB dissipate the heat caused during a PCB function. The function of the heat sinks depends on two elements, including copper coins and thermovia. You need specific components to mount the heat sinks on the amplifier circuit board.

Conclusion

The amplifier PCB has many uses as discussed above. You have to consider several factors while designing it. You can get the desired layout by controlling certain issues while creating the layout of an amplifier circuit board. You should also plan the type of amplifier PCB your device requires.

Would like to know more about designing a signal amplifier or PC Board assembly? Email us at sales@pnconline.com

Four Stages of PCB Design and Assembling

Four Stages of PCB Design and Assembling

PCB is a printed circuit board that helps connect different electrical components. The board is a combination of laminated material, and the copper foil laid on a non-conductive substrate.
A PCB is the main part of any electronic device, so it has to be perfect. It should have functional components and microelectronics circuits to perform well. Development of PCB goes through different processes that you should know well. PCB manufacturing has 4 stages, including design, manufacturing, PCB assembly, and PCB testing.

First Stage- Design

PCB design involves different steps, such as schematic design, layout planning, the placement of the components, routing, and manufacturing files.
PCB schematic design: It is a blueprint of PC design that shows all PCB components with symbols. The schematic design is always according to the technical requirements of the user.
Layout planning: After the schematic design, you have to develop the layout of a PCB that includes physical components’ models,the shape of the PCB, and the structure of a PCB.
Placement of components: It involves planning the placement of various components. You decide on the PCB layers according to your requirements. The right placement of the components ensures a flawless board, decreasing the production cost.
First of all, the designer places the fixed components in the layout, including switches and connectors.
Then, the critical components are placed, such as memory chips, microprocessors, as well as power supplies.
Then the supporting components of the PCB are placed, like inductors, capacitors, and resistors.
In the end, the decoupling capacitors and terminating resistors are placed.
Routing: Once the components are placed, you have to connect all components through trace routing. There are four ways to do so, such as manual routing, auto-interactive routing, semi-automatic, and batch-auto routing. You can choose any method according to your Printed Circuit Board and budget.
Design: In this stage, you have to plan for the number of board layers, dimension of the board, and types of components. You can use a special app in this case, such as EDA or electronic design automation. The designer often adopts the SMT instead of a through-hole technology, depending on your requirements.Once the design is over, you can export the design files to CAD or Gerber format.
Preparation of manufacturing files: This is the last stage of design where the designer exports the Gerber files for manufacturing. The manufacturer needs these files to develop a printed circuit board.

Four Stages of PCB Design and Assembling
Four Stages of PCB Design and Assembling

Stage 2-Manufacturing of Circuit Board

Once the manufacturer receives all design drawings, he starts making PCB. It involves different stages as described below:
Design Imaging:The manufacturer uses a plotter to convert the PCB design files into filmslike they resemble the photo negatives of the schematic design. The printer uses black and clear inks for inner and outer layers. Copper traces and circuits are shown with black ink, whereas the non-conductive parts are shown with clearink.
Printing of Inner Layers On Copper: It is the initial stage of PCB manufacturing. The engineer uses a substrate material to make a laminated board. Like, epoxy resin or fiberglass are common in this case. The design of the PCB is printed on the board, and then he pre-bondscopper on a board’s both sides. After that comes the etching of copper, and then the board is protected through a photo-sensitive film.
UltravioletLight: the manufacturer then exposes the resist-covered PCB to UV light to strengthen the photo-reactive material. Then the board is cleaned with an alkaline solution to get rid of unnecessary copper particles. The expert checks the board to remove any errors and then goes to the next stage. The main aim of UV blasting is to develop a PCB Board according to the schematic drawing.
Inner layer’s etching: copper’s inner layer needs chemical etching for removal. The process of photoresist prevents the essential copper from etching. The board size determines the amount of the solution and etching time which is less for small boards but more for large boards.
Some other manufacturing processes include:

  • Alignment of layers
  • Optical testing
  • Layer pressing and lamination
  • Drilling
  • Plating of PCB
  • Imaging of external layer
  • Etching of external layer
  • Solder mask
  • Silk screening
  • PCB finishing
  • Testing
  • Profiling
  • Quality testing
  • Packaging of PCB
  • Shipping of PCB

Stage 3-PCB Assembly

The assembly of a PCB involves four stages, such as soldering, placement of components, solder pasting, and testing. Let’s review them in detail.
Solder Pasting: It is like t-shirt screening, as it involves solder paste stenciling. The stencil is made of stainless steel and it’s very thin. You have to use the stencil to apply the paste in areas where different components will be installed. In this process, flux is used for melting the paste to help it bond to the PCB.
Placementofthe Components: Once you are done with the solder paste, you need a pick and place the tool for the components. Generally, it is SMT or surface mount technology where components are placed on the PCB surface. Initially, it used to be a manual process and assemblers used tweezers to pick and place different components on the board. However, new technology has made this process automated due to robotics and it’s more precise and consistent.
Soldering of PCB: After the placement of components, you have to place the PCB on a conveyor belt to help a board move to a reflow oven that heats the board. The heating helps melt the solder paste, and bond the components on the board permanently. However, if the board has more components other than SMDs, it would need a through-hole insertion that involves more advanced soldering.
Testing of PCB Quality: Sometimes, the components are misplaced during reflow when the PCB is moving. This issue may cause a poor connection, or no connection at all, or the parts are not well-connected. So, you need to inspect the PCB to ensure a flawless function. A PCB can fail this test even if it passed other tests, and a failed PCB goes to scrap or you have to recycle it with all essential processes until you get a flawless circuit board.

Stage4-PCB Testing

Manufacturers use different methods for PCB testing to ensure that it will function correctly. These methods include in-circuit, optical inspection, flying probe, turn-in, x-ray, anda functional test.
In-Circuit: It is also known as ICT, or you can call it the bed-of-nails inspection. In this method, PCB is pressed on the bed of probes. It is highly accurate because it checks all components of a PCB. You can also test the BGAs with this method. Moreover, it also tests the solder integrity of the bottom-terminated components.
However, this test is expensive and time-consuming. Moreover, it does not test the non-electrical parts and connectors.
AOI, Automated Optical Inspection: This testing method involves a visual inspection of the board. It is done with the help of HD cameras, LED lights, UV, and high-level infrared. The test is contact-free and helps check poor solder joints or missing parts. It also tests the smt assembly issues and it’s very accurate.
However, it only inspects the preprogrammed errors and can’t check defects regarding glue or sealing.
Flying Probe Test: It involves probes that help test the upper and lower surface of a PCB. This PCB testing method is cost-effective, consumes less time, is easy to do, and is compatible with many applications of PCB assembly. However, it is slower than other testing methods and not ideal for complex testing.
Burn-In Test: In this test, PCB is exposed to a high temperature to see if it works well. It ensures a lifetime product and enhances the brand because of an effective end product.
However, this test is costly and can affect a PCB by damaging its components. Moreover, it can be less reliable due to voltage scaling.
Inspecting Through X-Ray: It involves an x-ray machine that inspects a PCB. It thoroughly checks soldering which is hard to detect with AOI. The x-ray inspection is ideal for thick or multilayered PCBs. It also detects the voids or bubbles and can also check the components under a shield.
However, it needs expensive x-ray machinesand can cause hazards in the workplace.
Functional Test of PCB: It involves functional testers that you connect to the edge connector. It creates an electronic environment for which a PCB is made. It inspects the functional errors and identifies the analog issues. It also checks issues with digital circuitry.
However, it is very costly and needs high-end tools, which are too expensive. It needs a proper understanding of the working atmosphere of the DUT.

Final Thoughts

The development of a PCB involves different processes, including design, printing, assembling, and testing. Each stage is further divided into different parts, and you have to understand all stages to create a flawless PCB.
The board is a combination of laminated material, and the copper foil laid on a non-conductive substrate. A PCB is the main part of any electronic device, so it has to be perfect.
Would like to know more about the design or pcb assembly services stages? Email us at sales@pnconline.com

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