By Mer-Mar Electronics | Date posted: | Last updated: May 25, 2022
PCB Layout Tips

Once the PCB components are placed on the board and routed, any requirement that calls for a sizeable amount of rework, can prove to be extremely cumbersome. Not only does it take time that in turn impacts go-to-market and impacts your competitive advantage, it also comes at a cost. Additionally, if your board hasn’t been designed to support rework, it makes the job even more difficult. In such cases, rework can also impact other sensitive parts in the vicinity and lead to further complications.

Fortunately, there are some handy PCB layout tips and tricks, which if followed, can go a long way in reducing the amount of rework required.

Before we look at these tips, it will be worthwhile to examine what are some of the PCB rework issues that are typically encountered:


Part Replacement – Sometimes a wrong part may have been initially specified. A seemingly small lapse, it leads to wasted time, effort and costs.

Defects in Assembly – A big part of the rework is required when parts haven’t been soldered correctly during assembly. Sometimes these PCB soldering issues can be on account of improper DFM clearances or incorrect component locations.

Inaccessible Parts – Sometimes it is hard to replace parts or rework them, on account of the fact that the parts are either too close to other parts or sometimes even hidden. If the part is positioned in a manner that tools cannot reach them, it can be a big issue that can impact rework.

Damage – Parts that are placed very close to the components that need rework can also be damaged. The damage can happen on account of heat of soldering reaching these parts or any physical damage while replacing other parts. The rework process therefore may lead to reworking on these collateral damages too.

Needless to mention that rework also becomes a deterrent when you are chasing a deadline and also trying to keep things under budget.

PCB layout Tips to reduce post assembly rework

Here are top handy layout tips that when implemented well can go a long way in avoiding or minimizing rework issues:

  • Accurate BOM – Now this is a gold standard when it comes to avoiding rework. Sometimes the part information in the design isn’t updated or the schematic isn’t synchronized with the layout. In turn, it leads to reworking incorrect parts. It is imperative, therefore, that the BOM is totally in sync with the PCB design and layout.

  • DFM guidelines – A lot of the rework related to parts being placed in the wrong location or parts not soldered correctly can be avoided if the DFM guidelines are clearly specified and are followed accurately.

  • Room for rework – High density of parts is a function of miniaturization of devices. The components also need to be placed tightly together to ensure signal integrity. However given these constraints it is important to allow some room for rework. The PCB contract manufacturer will be in the best position to offer recommendations to be able to incorporate room for rework within the constraints.


As the complexity of a printed circuit board increases, so does the potential for rework. The right contract manufacturer given his expertise and access to industry best practices will be able to minimize the potential of rework. That said, even with all the precautions there will be some PCB assembly defects that can occur which an experienced PCB manufacturer will be able to cater to.

While potential rework situations need to be taken into account, what also need to be planned for are aspects such as:

  • Some printed circuit boards need additional testing.
  • Sensitive components need room for access. This may include additional vias for probing or header pins for test access.

An experienced and skilled PCB contract manufacturer can easily identify areas of the board that may need more room for rework or for extensive testing. Besides, a skilled PCB contract manufacturer will also have the engineering prowess that will be of utmost importance when it comes to meticulous rework in the least amount of time and with minimal added costs.

At Mermar Electronics, we have 4 decades of solid experience in assembling printed circuit boards, PCB design and PCB assembly rework and repair service through innovative tools and technologies. If you have any requirements or inquiries related to PCB manufacturing, Get a quick quote, or simply drop an inquiry at

By Mer-Mar Electronics | Date posted: | Last updated: February 9, 2022
RF Circuit Board Design

RF circuit board design is seeing increased usage whether it is in medical, industrial or communication devices. Simply put, RF signals are high-frequency analog signals. The RF frequency range is usually from 300 kHz to 300 GHz. This is as opposed to Microwave frequency range, which is anything above 300 MHz.

Even though RF PCBs have a wide range of advantages, compared to high-speed digital-signal board design, RF circuit board design also comes with its unique set of challenges. Let us look at these challenges in some detail as also look at effective tips that help designers mitigate these challenges effectively.

Challenges associated with RF Circuit Board Design

  • Sensitivity to noise – RF signals are highly sensitive to noise and lead to ringing and reflections. What is important is to ensure that the signal is properly terminated. It is also advisable to optimize the return path and ensure proper grounding is maintained.
  • Impedance Matching – Essentially frequency and tolerance are inversely related The higher the frequency, the smaller is the tolerance. If the total length of he trace is greater than the critical length i.e 1/16th of the wavelength of the signal, impedance control needs to be undertaken.
  • Return loss – It is imperative that return loss be minimized. In the absence of a good design, the return signal will go through power planes, or through multiple layers of the PCB. In such cases it will not be impedance controlled. For this reason, it is important that there are ground planes underneath the signals that can provide an impedance-controlled path. With ground planes, ground loop currents are minimized and also RF leakage into circuit elements is minimized.
  • Crosstalk – High Frequency designs also suffer from crosstalk. Crosstalk, in fact, is directly proportional to edge rates of the active line. Here the coupled energy from the active line is superimposed on the victim line. With board densities rising, so does the issue of crosstalk. To counter this, it is important that adequate space is left around the signal trace. Also it is important that traces are kept as small as possible. Also it is important that high-speed signals are routed as far apart. Reducing the dielectric spacing between the line and its reference plane, is yet another effective measure. Similarly, terminating the line on its characteristic impedance also limits crosstalk.
  • Other signal losses – Other signal losses include skin effect loss as also dielectric loss. PCB designers therefore need to look at laminate properties such as:
    • Dissipation Factor
    • Dielectric Constant Value

FR4 material for PCBs or laminate, for example, has a high dissipation factor. Insertion losses are therefore higher when using FR4. Also, the dielectric constant value of FR4 can vary up to 10 percent. In turn, this impacts impedance. High frequency laminates have more stable frequencies.

Coming to the Dk value itself, in microwave circuits the Dk value is linked to the size of circuit elements. It is therefore possible for a designer to reduce the circuit size by choosing a laminate that has a higher Dk value.

Effective Tips for RF Circuit Board Design

There are a number of effective tips that help in creating better designs and improving anti-interference. Some of these include:

  • Usage of inner layers as power ground layers. By doing this you will provide shielding and reduce spurious inductance. Reducing the length of the signal wire reduce cross-interference.
  • Turning the circuit layout 45 degrees. By doing this, high-frequency signal emission and coupling will be reduced. Short layout lengths work better for through holes. Also, the layout between layers should be vertical in order to reduce signal interference. It is also beneficial to increase copper on the ground layer.
  • Packaging important signal traces. This goes a long way in increasing the anti-interference ability of the signal. When it comes to signal traces it is also recommended to avoid loops and use a chrysanthemum link instead.
  • Bridging the decoupling capacitor. It is important to lay out the RF first and make the RF signal 50 ohms.
  • The importance of isolation cannot be overstated.

Incorporating these seemingly small suggestions can go a long way in creating far more effective designs and improving overall efficiency.

Mer-Mar Electronics is a certified and leading PCB manufacturer that gets things done in lesser turnaround time. We are committed to accurately reflecting your PCB design specifications as well as meeting the industry standards. We at Mer-Mar Electronics, assist our customers from initial design to mass production & delivery; as one of the leading electronics manufacturing services (EMS) providers. To know more contact us at or call us on (760) 244-6149.

By Mer-Mar Electronics | Date posted: | Last updated: December 23, 2021
aerospace pcb design

When it comes to manufacturing printed circuit boards for aerospace electronics, they need to have an extremely high degree of reliability. More so, as these need to operate in harsh environmental conditions! Since such mission-critical operations do not allow for any scope for error and need to stick to strict operating standards, there are some stringent guidelines that need to be followed.

Rules to consider when it comes to aerospace PCB design:

1. High Quality Components

Now this clearly makes sense. Since you do not have any scope for malfunction and maintenance interventions aren’t a possibility, it is imperative to use high quality materials and components.

For instance, one of the materials that is recommended to be used includes anodized aluminum as it helps in heat dissipation. In fact, its thermal conductivity is far higher than that of traditional materials.

2. Thermal Management

With aerospace PCB design What is required is effective thermal management. Therefore, you need to ensure proper heat dissipation without using external heat sinks. This can be done in several ways, including:

  • Use of heavy copper technology that allows heat dissipation without needing any additional cooling systems.
  • Use of thermal vias.
  • Use of materials such as Pyralux AP, FR 408 and other such materials.
  • Ensuring there is a reasonable distance between components to allow for heat dissipation.

3. Strict adherence to reference standards

There are fixed reference standards to be followed when it comes to PCBs for the aerospace industry. These include:

  • IPC 6012DS that lays down the performance standard for rigid PCBs for aerospace as well as military applications
  • AS/EN 9100, which is a series of standards developed by IAQG specifically for the aerospace industry.

4. Use of Conformal Coating in Aerospace PCB Design

Given the harsh operating conditions for aerospace PCBs, conformal coating is a step that cannot be avoided. Some of the conformal coatings include:

  • Electrolytic Nickel Gold
  • ENIG
  • HASL
  • Lead-free HASL

Such conformal coatings offer protection against heat, humidity and more. Once the conformal coating has been applied, the use of an acrylic based spray is prudent, as it protects the PCB from contamination as well as short circuits.

5. Routing Guidelines

It is important to choose the size of PCB traces so that they can handle the current load as also to ensure effective heat dissipation. It is recommended that the angles on the traces are less than 45°, so that the signal transmission is uniform. Additionally, it is important to separate components that operate at low frequencies from the ones that operate at high frequencies. This will ensure that the signal quality isn’t compromised. Also, the clock signals need to have proper physical shielding. It is also important to follow the rules to reduce crosstalk.

6. Use of flex and rigid-flex PCBs

The use of flex and rigid-flex circuit boards is widespread when it comes to the satellite, aviation and aerospace industries. However, as compared to industrial applications they are made of polyamide as opposed to FR-4. The advantages that it offers include:

  • It can adapt to small spaces.
  • It is light.
  • It is heat resistant.
  • It has high durability.

In fact, flex and rigid-flex PCBs offer high resistance to vibrations and shocks besides offering great mechanical and electrical connections. In addition, they work well in limited space applications. With their use, secure connections can be managed offering polarity and contact stability.

7. Aerospace PCB Design Testing

Above everything, what is required is robust testing. In fact, you need to go through a whole lot of testing loops to ensure that the design is reliable and will work well in the aerospace environment, which means working in zero-gravity in a vacuum as also working in extremes of temperature, depending on whether they are working on a low-orbit or geostationary satellite.

To sum up

With aerospace PCB design and manufacturing, the aim must be to offer high reliability even in the most difficult operating conditions. To this end, right from design to selection of right materials can all ensure that the PCB offers a failure-free operation. A robust board will ensure that it can resist g-force vibrations, thermal issues and more.

Mer-Mar Electronics is one of the leading aerospace PCB design and manufacturing companies that specialize in building ITAR compliance aerospace PCB assembly. We are committed to accurately reflecting your design specifications as well as meeting the aerospace industry standards. We at Mermar Electronics, assist our customers from initial design to mass production & delivery; as one of the leading Aerospace electronics manufacturing services (EMS) providers.

By Mer-Mar Electronics | Date posted: | Last updated: December 23, 2021
medical grade pcb design

The medical industry has shown an unprecedented evolution in the development of medical devices. As the new diseases take birth, we need to brace up to the situation and upgrade the equipment to handle any sort of challenges. Very rightfully, PCB design and manufacturing companies have been tirelessly developing devices for testing novel diseases. New trends have emerged in building medical device electronics. Innovation & flexibility have become the standard principles of PCB design and manufacturing. PCB manufacturers have been quick to find ways to innovate and adapt to the changing landscape in the medical industry.

In this article, let us find the latest trends in medical PCB design and manufacturing and how your CM can best respond to the emerging trends in the medical industry.

Trends in Medical PCB Design

The medical industry is dynamic with several advancements happening in the market. Recent advances that are currently in the market include robotics, wearables, machine learning, and AI-based software, higher resolution computer vision, and more. One needs to keep up with the latest innovations and PCB design trends.

High-power boards, open & transparent communication and other factors are quickly reshaping the medical-grade printed circuit boards.

Some of the latest trends in the foreseeable future are listed below. Choose a CM that keeps up with these latest Medical PCB design trends.

  1. Smaller the better

    The printed circuit boards for medical device electronics are becoming smaller and denser. The component placement density has increased. This is reducing the margin of error on the boards facilitating the adaptability in PCB designs. Thin and lightweight PCBs help you in heat dissipation.

  2. High power boards

    There has been an increasing demand for high-power boards. It can accommodate more abundant components. Typically, higher voltage levels operate in the range of 24 to 48 volts. Thermal design should be optimized, and heat dissipation should be minimized for high-power boards.

  3. Non-standard PCB Form-Factor Designs

    With more health awareness among the people, many have been attentive to their body and mental health. They have been investing in self-monitoring health devices for exercise, wellness, and other medical conditions. This has led to non-standard Printed circuit board form PCB design factor.

  4. High-density Interconnect (HDI) Boards

    Smaller boards that provide higher functionality and tighter interconnectivity paths with very less area for traces. And for the same reason, many medical boards go for the deployment of HDI boards.

  5. Flex Structures

    Flexible electronics with special manufacturing needs have to be incorporated into the PCB designs and this has picked up momentum in recent years. These are excellent options since you have space, weight, and size limitations. These are also better-suited for high-temperature and high-density applications.

  6. IoT Usage

    IoT is everywhere. Device interconnectivity is much needed for improving medical systems. We need smart data transfer which would be made easier with the help of IoT. Hence designing PCB assemblies for IoT is now a much-needed necessity. IoT-ready PCBs should also meet rather stringent standards and regulations that govern their manufacturing.

  7. Spread of COTS Components

    There are commercial-off-the-shelf components (COTS) that help in speeding up and improving the design process. You can achieve a higher degree of reliability and efficiency with these. But make sure you receive PCB products from a reputable source.

PCB Manufacturing Trends in Medical Systems

We are currently living in a world that is undergoing a fourth industrial revolution where the physical and digital boundaries are blurred. The communication systems and software have to improve the manufacturing speed and efficiency. To ensure optimal medical-grade PCBs, we need to incorporate the latest manufacturing PCB trends.

  1. PCB Design Intent

    The best way to incorporate the design intent throughout your PCB build process is to collaborate with the right CM partner early on in the development.

  2. Digital Twin Technology

    Under PCB manufacturing, digital twin technology helps you to prevent waste and also mitigate development costs. You can identify any potential errors even before the first board is out in the market.

  3. Optimize DFM and DFA Usage

    Optimize your medical PCBA development to meet a high yield rate. Also, let your CM use DFA and DFM standards and guidelines.

  4. Transparency

    Maintain open and transparent communication with your CM from the beginning so that you can have seamless collaboration between your CM and you for your medical-grade PCBs.

  5. Agile Manufacturing

    PCB manufacture can incorporate PCB design changes iteratively with minimal production disruptions.


Several key standards and regulations have to be complied with and adhered to while designing medical electronic devices to ensure the safety of both medical professionals and patients.

  1. However, any major technological breakthrough takes years to see the light and make an impact in the market. This is because, while we make improvements in the product design, there would be longer intervals to get the distribution approvals as one needs to make sure that all the necessary safeguards are in place.
  2. Raw material supplies also dry up and it also becomes difficult to procure. Even customer demands change and reshape product design and development.


PCB design and manufacturing trends are likely to disrupt the current market trends and would show positive momentum in terms of design innovation, reliability, and performance. PCB industry as a whole is evolving but more specifically in the medical industry niche.

You can go for a certified and experienced CM for building high-quality and error-free PCB assemblies for medical systems. The CM should be able to meet the rigorous medical industry standards as they would be of utility where human lives are at stake.

Mer-Mar Electronics is a certified and leading PCB manufacturer that gets things done in lesser turnaround time. Our team works on medical-grade PCB development for delivering high-quality equipment with superior support. To help you get started, we furnish some information for DFM checks and you would be able to easily see and download DRC files. Get in touch with us to know more about our medical PCB design and manufacturing services.

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