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Physical and Electrical Partitioning In PCB Design

Physical and Electrical Partitioning In PCB Design

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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

PCB Design, Planning, and Components Selection in Printed Circuit Boards

PCB Design, Planning, and Components Selection in Printed Circuit Boards

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Designing a printed circuit board or PCB can become challenging because there are many factors to consider, including environmental conditions the PCB will be exposed to and the desired electrical components that the PCB will use. The best design, planning, and component selection bring the best-printed circuit boards. All electronic products contain printed circuit boards so considering the above elements is essential that we will discuss these elements in this article.

Questions Regarding PCB Planning?

A few questions to keep in mind when designing and planning a PCB include:

  • How many layers do I want?
  • What thickness of copper foil/laminate do I want?
  • Do I want to use plated through holes or non-plated through holes?
  • Do I want my board to be double-sided, single-sided, or multilayer?
  • Are all of my components going to be surface mount or through-hole?
  • Are all of my connections going to be made using jumpers or solder pads?
  • Can I get away with using cheaper non-plated through holes instead of plated ones? Can I get away with not having a ground plane layer if all my signals are digital logic levels?
  • Does my design require low-noise analog filtering?
  • Will I need to isolate high-voltage circuitry from low-voltage circuitry, and high-speed circuitry from slow-speed circuitry?

You can start designing a PCB after getting answers to the above questions.

PCDesign: Basic Guidelines

Before you even begin to design your printed circuit board, make sure you understand some basics of PCB design. When designing a Printed Circuit Board several things should be considered. Keep in mind that most errors caused by circuit boards are usually associated with improper grounding and power distribution.
If you are trying to create a custom PCB or just update an existing board, it is important to consider whether it will be surface mounted or through-hole mounted.
Size: The size of your circuit board will also play a big role to see how much space you have for components. You can either choose to go with a larger board and have less room for components or vice versa.
Layers: The number of layers in your circuit board also plays an important role to see how many components you can fit into one area. There are three basic types of circuit boards, such as single-sided, double-sided, and multi-layer. Single-sided circuits only have traces on one side while double-sided circuits have traces on both sides of a sheet of material called laminate. Multi-layer circuits consist of multiple layers stacked together which increases current capacity.
It is important to know what type of circuit board you will need before starting any design work because it may require special tools or materials that aren’t available at home orin local electronics stores.

PCB Design, Planning, and Components Selection in Printed Circuit Boards
PCB Design, Planning, and Components Selection in Printed Circuit Boards

PCB Layout Techniques

While surface-mount technology dominates today’s electronics designs, you still may need to design or repair an older circuit that uses through-hole components. Whatever your reason is for dealing with through-hole components, there are several layout techniques you should be aware of to ensure reliable operation.
Many PCB layout problems stem from poor component placement rather than PCB material defects. By following these best practices when laying out a PC BOARD using through-hole components, you can help avoid these common mistakes If possible.

  • Place resistors before capacitors on each side of a power supply line. This way, if any capacitor fails, it will not causedamage to the resistors placed after it.
  • Place decoupling capacitors close to the chip they are used for decoupling. For example, if you have a microcontroller with two crystal oscillators, place one cap near each oscillator and connect them at opposite corners of their respective pads.
  • Placing both caps near only one oscillator would increase the parasitic inductance between those two connections, reducing efficiency.
  • Don’t place any other traces within 0.5mm of a signal trace running parallel to another signal trace on different layers. Signal traces running parallel are said to be coupled and can pick up noise from each other due to electromagnetic induction caused by nearby power or ground planes.
  • Try to keep traces spaced away from each other by 1mm or more if possible. If you must cross a signal trace over another signal trace, do so at right angles and use wide traces to reduce coupling.
  • When placing multiple closely-spaced power/ground pins on a single side of a DIP package, leave enough room between pins for solder mask relief cuts. Otherwise, you could end up with a solder mask bridging across adjacent pins when you remove your stencil during soldering operations.
  • Never put a hole in a signal trace and even small holes can cause shorts to the surrounding traces and components, especially if you don’t seal them off with liquid electrical tape or conformal coating. Similarly, don’t drill holes in the ground or power plane areas because those holes could become filled with solder during soldering operations.
  • Drill larger holes for mounting standoffs instead of smaller ones for mounting screws to save time and improve manufacturability.
  • Keep in mind that you may want to place components on a PCB around a standoff if you plan to solder wires or connectors directly to it. Always use solid core wire for power and ground traces. Stranded wire has too much resistance and tends to break easily under repeated flexing.
  • Keep track of your trace lengths to make sure none are longer than 2-3 times their widths. Longer traces can affect signal integrity and lead to intermittent failures in your final product.
  • When possible, use a ground plane layer to provide a return path for your power and ground traces. Power and ground planes also act as heat sinks, helping to dissipate heat from your components.
  • If you can’t use a separate ground plane layer for some reason, try to place as many of your signal traces on that layer as possible. That way, if one trace causes a problem with another trace or component, it won’t affect any other traces running on that layer.

Components Selection for Printed Circuit Boards

Deciding what components to choose when designing printed circuit boards is an important process that affects your final product. These electronic components come in many shapes and sizes, with different specifications for power consumption, weight, and other factors.

Knowing how to choose your components efficiently can prevent expensive mistakes down the line. This guide will help you understand how to select components for your PCB design effectively.

A printed circuit board contains conductive tracks made from metal foil and a conducting adhesive, typically etched into a thin layer of non-conductive material such as fiberglass or epoxy resin. Components are then placed on these tracks at specific points called pads, which are connected by copper traces forming circuits.
The PCB is usually used to connect electronic components like resistors, capacitors, transistors, and diodes with each other to form an electrical circuit. The most common materials used for PCBs are FR4 (fiberglass) and G10 (FR4 glass laminate). Other materials include CEM-1 (glass epoxy), Rogers 4003 (aluminum), Rogers 4350 (aluminum), and PTFE-based laminates.

The Purpose of Design

When designing printed circuit boards, many factors need to be considered and you can split them into two categories, such as functional requirements and design constraints.
The functional requirements describe what your printed circuit board needs to do, while design constraints determine how it will be designed. For example, if you want your product to have a battery life of more than five hours you need to consider things like battery size and power consumption when designing your product.
Functional Requirements
Four main functional requirements must be met when designing printed circuit boards, such as performance, reliability, serviceability, and cost.
Performance refers to how well your product performs its intended task.
Reliability means that your product should work correctly all of the time without fail.
Serviceability means that it should be easy to repair any problems with your product once they occur.
Cost refers to whether or not you can produce your final product for a reasonable price.
These requirements may change depending on who your target market is. If you are targeting high-end consumers, reliability and serviceability might take priority over cost. On the other hand, if you are targeting low-income customers in developing countries, affordability might take priority over everything else.

Connectors for Printed Circuit Boards

Solderless connectors are used to connect different electronic components on a printed circuit board. They’re available in two categories, such as through-hole and surface mount.
These connectors can also be classified by their location on a PCB, such as an edge-mounted or through-hole mounted. The primary difference between these two is the size.

Edge-mounted connectors are smaller than through-hole ones because they don’t have as much copper around them. This makes them better suited for smart devices having less space, such as cell phones and laptops. Whereas the through-hole mounted connectors are larger and easier to work with but require more space on a PCB.

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Printed Circuit Board Routing Practices after Auto Routing

Printed Circuit Board Routing Practices after Auto Routing

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In electronic design, PCB routing is the positioning of conductive pathways on a printed circuit board before final soldering and interconnection. The purpose of PCB routing is to have an arrangement where signal traces connect electrically to components and other signal traces while avoiding the signal crosstalk and maintaining short electrical paths between the components.
You can have a manual PCB through computer-aided design software or the use of specialized routing hardware, such as manually controlled routers or auto-routers.

How To Reset Your Board After Auto Routing

If you’ve used an auto-router, but you’re not happy with its results, you can fix it in different ways. Moreover, if you know what a DRC is, you can use it to override certain errors that auto-router made.
DRC means the Design Rule Check which you can perform by running an ERC or Error Report Check. The ERC will report all of your errors on your design file on a text file. It will then tell you how many errors are found in each layer.
You can then go into each layer and manually change any error that was reported by using the P-CAD’s drag function to move components around until they fit perfectly within their pads or tracks. This is also known as drag fitting.
When everything fits perfectly, save your design as a new version so that you don’t accidentally erase anything important. Once saved, run another DRC and see if it finds anything else wrong with your board layout. If not, continue with another step to check for shorts between traces/pads/vias/traces, etc.
After fixing these issues, perform another DRC again. Now that everything looks good, export your Gerber files. Make sure you select the top copper layer only and then hit OK. Your Gerber files should now be ready to send off for PC Board Fabrication.

How To Manage Multiple Copies Of The Same Net

In printed circuit boards, nets are electrical connections between different parts of a design. For example, if you have an LED that is connected to the ground and another net that connects to a microcontroller through various resistors, there will be two nets connecting these two components.
You need to route one copy of each net in your board file in order for it to be used in your design. Having too many copies can make it difficult to update or change an element of your circuit board design.
In case you have several copies of a net, they will all be shown in different colors. But, you should always try to join them together instead of having multiple copies. The PCB editor provides a Merge Nets option which can do that for you. To use it, just click on it in one of your nets and select another net for merging. You can do that with as many nets as needed. When finished, press OK and then Save Board to save your changes. You can easily learn it through various video tutorials available on the internet.

How to Manage Tight Spaces in PC BOARD Routing

The key to successfully routing a PCB with tight spaces is in visualizing what you’re doing. If you can see it, you can do it. Once you have a clear picture of your goal, there are several techniques to deal with PCB obstacles that make it possible to route those hard-to-reach traces. Here are some tips on managing tight spaces.

Place your components as close together as possible: This will leave plenty of room for routing at either end of each component lead.

Put components with shorter leads toward one side: This allows more space for routing on other sides, where longer leads might overlap.

Use right-angle headers instead of straight headers when possible: They’re easier to route around obstacles because they have a narrower footprint. If you can’t use the right-angle headers, place them closer to an edge than a corner.

Use large-pad ICs instead of small-pad ones when possible: Large pads make it easier to route around them without accidentally overlapping their neighbors.
Put components with longer leads toward one side: This allows more space for routing on other sides, where shorter leads might overlap.
Place through-hole components near an edge: This leaves plenty of room for routing on other sides, where smaller holes might overlap. It also makes it easier to access component pins from both sides.
Route clockwise around obstacles when possible: Clockwise routing tends to be smoother than the counterclockwise routing because it keeps your drill bit moving forward rather than backward.

Tips On Hard-To-Route Pins, Vias, Signals, Planes, And More

One of the biggest advantages of auto-routing tools is that they save you a ton of time by automatically planning out your board’s signal paths. Though these tools are very convenient to use, there are certain types of signal paths that can be very difficult for them to handle.
Here’s a quick rundown on some common hard-to-route signal paths and what to do about them, so you can make sure your PCB design doesn’t have any issues during production.
Multi-layer boards allow you to create more complex circuit layouts than would otherwise be possible with a single-layer PCB. But, when it comes down to it, most manufacturers prefer single-layer boards because they don’t cost much more and will typically get you faster turnaround times than multi-layer boards.
If you’re trying to decide between single-layer and multi-layer, here are a few things to keep in mind:
Multi-layer boards require additional fabrication steps. Though multi-layer boards do indeed allow for more routing options than their single-layer counterparts, they also require additional fabrication steps which increase the manufacturing costs. This means that unless you need those extra layers, it’s probably best to stick with a single-layer board.
The single-layer printed circuit boards can fit more components. This may seem like an obvious point, but when designing your layout, remember that multi-layer boards have smaller component pads and traces than their single-layer counterparts. Each layer adds another set of traces and pads. So, if you’re looking to fit more components onto your board, you should consider sticking with a single-layer PCB.
In other words, both multi-layer and single-layer PCBs have their pros and cons. So, if you aren’t sure whether or not you should use one over another, or if you simply want to play it safe, go ahead and choose a single layer board instead.

Printed Circuit Board Routing Practices after Auto Routing
Printed Circuit Board Routing Practices after Auto Routing

Avoid Over-Relying On Auto-Routing

Though auto-routing is a great help, you cannot over-rely on it. Besides, you have to select the right software for this purpose. There are lots of free software available on the internet which might or might not work well in this case, so choose carefully. You should have practice to route traces with any software that we will discuss further. Besides, there are different parameters of auto-routing that should be precise, however, they vary from project to project or between different modules on a single printed circuit board.

Top 5 Tips for Manually Routing A Circuit Board

There are different things to consider while manual routing on PCB, such as:
1. Keep your route sizes as consistent as possible: Having a fixed grid is highly beneficial when it comes to routing. You should lay out your design in a way that allows you to connect pin-to-pin with no more than 5 percent variation from expected routes. It ensures an optimal layout before starting any manual routing work.
2. Use proper start and endpoint selection: Starting a route at a pad or component lead not only wastes time but also affects a board’s signal integrity. To avoid these issues, always use endpoints or pins for start/endpoints whenever possible.
3. Avoid using vias for signal layers: Vias are used for connecting two different copper layers on a PCB, not for connecting two pads on one layer. If you need to connect two pins on one layer, consider using micro-vias instead of traditional vias.
4. Don’t overlap traces: Overlapping traces can cause different kinds of problems, such as ground loops and impedance mismatches. So, make sure you leave enough room between each trace for easy soldering and troubleshooting later on.
5. Focus on long-term flexibility: Once you have routed your board, think about how you might want to change it down the road. For example, will you ever want to add another connector? How about changing around some components? You may find that adding the solder mask artwork into your design software now will prevent you from lots of headaches later on.
Your ability to change the designs without having to reroute everything from scratch makes a huge difference in future productivity and costs. The best way to learn new skills is by doing new things, so don’t be afraid to take chances and be innovative.
You can develop the best PCB by focusing on different techniques and design parameters for which you can also read our other posts.
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PC Board Debugging & Troubleshoot Guidelines

PC Board Debugging & Troubleshoot Guidelines

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Engineers have to test the PCB thoroughly to see if it’s functional and fulfills its purpose of design. But, some manufacturers don’t do it which leads to intermittent issues or PCB failure, and such issues are hard to deal with while debugging. Whereas it becomes a disaster if a PCB fails in the field. You can avoid PCB issues by testing it thoroughly, besides it should be built by a good manufacturer. First, you should know the basic troubleshooting methods, so let’s begin.

Basic PCB Troubleshooting and Debugging

PCB of a printed circuit board has copper traces and insulators to connect heavy components to develop an advanced circuit. It is a great challenge to troubleshoot a circuit board in terms of thickness, size, signals, layers, and the types of different components as they are all very important.
Some circuit boards are simple and don’t need a deep inspection, but there are also complex PCB designs that need special tools for troubleshooting. Generally, the basic test is easy to do through ordinary equipment to assess the currents, traces, and signals on the PC Board.

Choosing the Right Tools

Simple troubleshooting of a Printed Circuit Board involves a few tools, such as a multimeter which is quite common. But, deep troubleshooting of complex boards depends on high-end tools, especially if the problem is big. Like, you will have to use the oscilloscope, an LCR meter, a logic analyzer, and the power supply to assess a circuit board’s response in terms of function.

A Visual Inspection

Initially, you have to test your circuit board visually to see some obvious issues, such as overheating, overlapping of traces, burnt or damaged components, as well as the missing parts of a PCB. You can detect the burnt components through smell as they are not easy to detect otherwise. PCB components often get burnt due to overheating or excessive current. Sometimes the components bulge due to high temperature or heat which helps you identify the damage, like in the case of electrolytic capacitors.

PC Board Debugging & Troubleshoot Guidelines
PC Board Debugging & Troubleshoot Guidelines

Physical Testing

After visual inspection of your PCB comes the physical testing by applying the power to the board. You can easily find hot spots on the circuit board by touching its surface. So, you don’t need a costly thermographic camera to find heated areas. After finding the hot parts, you should cool them with compressed air to see how PCB components function at low temperatures.

How To Troubleshoot Or Debug A PCB Deeply

Experts use four techniques for PCB tests which come up with both pros and cons. Some common methods are ICT, cable scan, flying probe, and a functional test, so let’s study them one by one.

1: The Flying Probe Technique

This method of PCB troubleshooting involves multiple probes that check the PCB by flying around. Like, there are two to six probes in this case. This technique is ideal for large circuit boards, like backplanes. It is also cheaper than the ICT, and it debugs the pcb assembly issues that occur due to poor solder connections. The flying probe also checks components’ presence and their polarities and different values. It is a simple test and can handle the revisions of a PCB.

Cons of The Flying Probe

The flying probe techniques have some flaws in terms of PCB functionality testing, unlike ICT. The flying probe also works slowly compared to ICT because several probes contact the entire PCB testing points. However, it is ideal for low volume PCBs and its total cost is also lower than other techniques.

2: ICT Or In-Circuit For PCB Troubleshoot

The ICT is a PCB testing technique that involves multiple probes which are also called the bed of nails. In this process, the ICT probes connect with the testing points of the entire PCB to check its circuits to see if the assembly is correct or wrong. Like, it tests the bad solder joints or short circuits.

This method can perform even a deeper test by adding other modules or adapters to it. ICT also tests the overall function of PCB and values of the critical components.

Cons Of ICT

Though ICT is a great tool for PCB testing, it has some disadvantages too. Like, it has costly fixtures ranging from $8000, and they go up to $ 15000. Besides, the cost increases with any changes in the technique.

You can have maximum benefits from ICT if the technician knows the testing software and other tools. ICT is the best method for large volume testing.

3: The CableScan

Another troubleshooting technique is the cablescan, which is ideal for PCBs with several connectors having a complicated interface, like the backplanes. The tester attaches the cablescan with the circuit board and it tests all the pins against each other to evaluate the assembly issues, like a solder opening or shorts.

Cablescan also helps check jumpers’ configuration and quality of the diode, besides, it also accesses the capacitance and resistance.

Cons Of Cablescan

There are some flaws with cablescan due to its limits. Like, you have to see the size of the connectors it can test in one go. Moreover, it involves an additional cost to create the hardware interface.

You have to get wetting connectors, but their wiring with the system gets delayed due to the cost or other issues. The cablescan technique and its setup take lots of time, depending on the number of connectors and their complexity.

4: Functional Testing Technique

Another essential thing is to see if a PCB is ready to function or not. The functional test consists of test probes, software, and connected cables, and it determines PCB behavior according to design specifications.

The CM can also create the hardware and software or test fixtures to test the PCB function. This process is ideal for simple and small PCB layout designs. The engineers also develop fixtures for a bench test and make a plan to target the assembly issues involving less time and cost to assess the components. The functional test also helps see if the entire circuitry is working as you want. However, you need detailed debugging to find different faults and remove them.

Role of Engineers and Technicians In PCB Troubleshooting

You need experienced people to troubleshoot a PCB, such as engineers and technicians. Besides, these experts should know how to use the testing tools. Like, in the case of ICT, the engineer should know how to test the semiconductor. He should also know the DFT, end-user applications, as well as ICT optimization. The knowledge of hardware and software development is equally important.

When it comes to the cablescan, the troubleshoot company should have a huge inventory of already built connector interfaces. You can reduce the development cost and time by having all resources in hand.

Likewise, the technicians should debug with a flying probe according to the circuit board. In other words, the testing method should be compatible with the PCB design.

Most engineers use the LabView for a functional test, as it works according to the frequencies, variable supply levels, and several other PCB requirements. Such a deep examination of the PCB involves less amount of hardware, unlike surface-level testing.
Both basic and deep troubleshooting methods help you to find the right PCB issues, leading to an effective product by removing those issues.

Frequently Asked Questions

What Is ICT In PCB Troubleshooting?
ICT is a PCB testing technique that involves multiple probes which are also called the bed of nails. The ICT probes connect with the testing points of the entire PCB to check its circuits to see if the assembly is correct or wrong.
What Is The Flying Probe In PCB Debugging?
This method of PCB troubleshooting involves multiple probes that check the PCB by flying around. There are two to six probes in this case. This technique is ideal for large circuit boards, like backplanes. It debugs the assembly issues that occur due to poor solder connections.

What Is The Role Of A Functional Test In PCB?
The functional test consists of test probes, software, and connected cables, and it determines PCB behavior according to design specifications. The functional test also helps see if the entire circuitry is working as you want.
Is Basic Troubleshooting Enough For Circuit Boards?
No, the basic testing involves only visual and physical tests at basic levels. You need deep testing with specific tools, especially for complicated circuits.

Final Thoughts

PCB of a printed circuit board has copper traces and insulators to connect heavy components to develop an advanced circuit. It is a great challenge to troubleshoot a circuit board in terms of thickness, size, signals, layers, and the types of different components as they are all very important.
Some circuit boards are simple and don’t need a deep inspection, but there are also complex PCB designs that need special tools for troubleshooting. Generally, the basic test is easy to do through ordinary equipment to assess the currents, traces, and signals on the PCB. Whereas deep troubleshooting involves different techniques.
Would like to know more about PCB debugging, troubleshooting printed circuit board assembly? Email us at sales@pnconline.com

Identify SMT Components Polarity on a PC Board

Identify SMT Components Polarity on a PC Board

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The design of PCB and its assembly involves different components. The smart era has resulted in a compact PCB design and the components’ polarity is hard to identify now. Here, we will see how to recognize the polarity of the SMT components to avoid its reversal during production, ensure a correct PCB, and enhance the quality of engineers’ knowledge regarding the polarized components’ direction.

Understand the Polarity of Components In PCB?

The polarity of SMT components is the position of the SMT components’ first pin or it’s the direction of the component. In other words, when you mount a component during the SMT assembly process, it should be installed in a specific direction and that is polarity.
You have to make sure that both negative and positive poles of the components are connected to the circuit board. If the components’ direction is wrong while mounting, it would result in a blocked circuit, causing a short circuit. Moreover, the body of the component gets burned and the circuit does not function correctly due to wrong placement.

Polar Components and Their Type

PCB has several SMT components having polarity, such as
• Shaped capacitors
• Transistors
• Diodes
• Field effect tube
• IC integrated circuit
• Coil
• Crystal oscillator
• Transformer
• Shielding frame
• Row socket

All these connectors have different symbols, however, there are also several other types of components.

Marking of Polar Components

Components with polarity have specific marks that show the direction of both poles or the direction of the components’ first pin. The two-pin components have mostly positive and negative marks. Whereas in the case of multi-pin components, the mark is the placement of the components’ first pin.

The poor reverse happens if the circuit board has polar components with the wrong polarity. Reverse components are not suitable in terms of Printed Circuit Board function even their mounting and soldering are fine on the board pad. This issue can also burn the PCBA while testing it, making the board less functional.

You have to identify the SMT components’ polarity considering a few things

Identifying The Body Polarity of The Component

It is the position or direction of components’ positive and negative poles. You can also say that it is the first pin of the part marked on the component body.

Identifying the Component Polarity in The Circuit

• It is the position or direction of the positive and negative poles of electronic components. It can also be the direction of the first pin in the circuit.
• Another thing to consider is the mounting of the electronic components on the PCB. Whereas the component body’s polarity corresponds to the circuit’s polarity.

PCB has electronic components mounted on it through surface mount technology. The component body’s polarity corresponds to the circuit’s required polarity.

Printed circuit boards made by SMT are getting more integrated with precise components layout. Moreover, the components are getting smaller than before due to smart PCBs.

In mobile phones’ motherboards, you won’t find any components. So, you can’t identify the components’ polarity intuitively. In such products, the components tag map is used to create a material release map to identify the polarity, and the location specification to help quality personnel ensure the first piece which also becomes a sample for testing. This test ensures a flawless identification of the component polarity.

Identifying the Capacitor Polarity

• The chip resistors have no polarity.
• The ceramic capacitor is non-polarized.
• Polarity of the tantalum capacitors is determined by positive and color band marking of the components on PCB and diagonal marking.
• The capacitance and electrolysis of aluminum come up with polarity. The color band of components shows a negative marking. Whereas the PCB mark is positive.

Identifying the Inductor Polarity

• There is no need to identify the polarity for a chip coil package and welding areas.
• There are polarity requirements for multi-pin inductors. The polarity point is indicated by dot/1. Whereas the PCB mark is indicated by dot /circle / “*” for the polarity point.

Identifying the Diode Polarity

The surface-mounted LED in PCB has polarity. The components’ negative polarity is indicated by green. Whereas PCB’s negative polarity is indicated by the vertical bar, color band, and silk screen’s sharp corner.

Identifying the IC Polarity

• You can identify the polarity of the integrated circuit through SOIC packaging. It is indicated as a color band, groove, symbol, concave point, and bevel.

• The polarity of the SOP and QFP packaging is indicated by groove, concave, and two different points.

• The polarity of the QFN packaging is indicated by a beveled edge to the marking, a symbol like a horizontal bar, and two different points in terms of size and shape.

Identifying the Polarity of Ball Grid Array, BGA

In this case, the component polarity is indicated by a dot, concave point, groove, and a circle mark. Whereas the PCB polarity is indicated by dot, circle, and diagonal to mark. Moreover, the components’ polarity point corresponds to PCB’s polarity point.

Things To Consider In PCB Manufacturing For Components Direction

PCB assembly gets wrong if the components are not compatible with their orientation. However, certain warning signs regarding the PCB design guidelines can help in this case. The manufacturer has to consider a few things while reviewing a PCB design, such as:

Quality of design: the CM can enhance PCB production by finding the defective parts during assembly and replacing them with the right material or parts.

Standard assembly: PCB design should be compatible with assembly and the CM can ensure low-cost manufacturing by reducing the time and labor.

Assembly issues: the CM can also enhance PCB production by removing the potential assembly problems. This can also reduce the overall assembly cost due to reduced time and labor.

Thermal performance: certain components have to be positioned at a certain angle to enhance the airflow around the circuit board. This step keeps the parts cool and effective.

PCB going through a solder reflow also has issues with components orientation. Sometimes, the passive parts are placed together to connect all the pins to one power bus. When the direction of such components is unable to change, the power bus connection should be through a thin trace to remove the large metal areas that flood the pin.

The passive components having irregular metal connections between two pins might be vulnerable to floating on the pad surface or can cause tombstoning in solder reflow.

The direction of the parts is also a concern if they lie on PCB edges. In the case of V-groove scoring, the direction and placement of the components should allow some space for the scoring tool to work. It helps to remove the defects in PCB and the parts also stay safe. Moreover, you should also consider the direction of the components in terms of their function.

Identify SMT Components Polarity on a PC Board
Identify SMT Components Polarity on a PC Board

Frequently Asked Questions

What Is SMT Component Polarity In PCB?
The polarity of SMT components is the position of the SMT components’ first pin or it’s the direction of the component. When you mount a component through SMT, it should be installed in a specific direction and that is polarity.
What is SOP in PCB?
SOP means the small outline package that is an IC package of SMT.

What is QFP in PCB?
QFP in PCB means the quad flat package and it is also an integrated package for surface mounting.
What is QFN in PCB?
QFN in PCB means the quad flat no-lead package and it is leadless, small, and provides heat dissipation in PCB.
What are some SMT components with polarity?
PCB has several SMT components having the polarity, such as shaped capacitors transistors, diodes, field-effect tube, IC integrated circuit, coil, crystal oscillator, transformer, shielding frame, and the row socket.

Final Thoughts

The polarity of SMT components is the position of the SMT components’ first pin or it’s the direction of the component. In other words, when you mount a component through SMT, it should be installed in a specific direction and that is polarity.
You have to make sure that both negative and positive poles of the components are connected to the circuit board. If the components’ direction is wrong while mounting, it would result in a blocked circuit, causing a short circuit. Moreover, the body of the component gets burned and the circuit does not function correctly due to wrong placement.
Components with polarity have specific marks that show the direction of both poles or the direction of the components’ first pin. The two-pin components have mostly positive and negative marks. Whereas in the case of multi-pin components, the mark is the placement of the components’ first pin.

The poor reverse happens if the circuit board has polar components with the wrong polarity. Reverse components are not suitable in terms of PCB function even their mounting and soldering are fine on the board pad. This issue can also burn the PCBA while testing it, making the board less functional.

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