Tag Archives: Circuit board fabrication

Printed Circuit Board Signal Conditioning Process

Printed Circuit Board Signal Conditioning Process

The process of data acquisition is known as signal processing. This acquisition is done by an instrument which is known as the signal conditioner. There is a conversion of signals that happened in this process. The signal conditioner converts the signal from one form such as electrical or mechanical to another form. The input signal is converted into the output signal in the signal conditioning process. Now the question may arise why do we need to convert the input signal into an output signal? The simple answer is that the signal needs to be amplified.

This amplification helps the signal to be converted into a compatible and easy-to-read form. This form of signal helps in data acquisition and machine control. Analog signals are converted into digital signals but before that, correct preparation is made. In the signal conditioning process, we manipulate a signal in a way that it can be converted and further proceed for the next step. Mechanical and environmental measurements are made in many electronic acquisitions for the measure. These measurements are done with the angle of specific sensors such as temperature and vibrations. But these sensors cannot work accurately for the measurement of the signals if the signal conditioning is not compelled yet.

Certain signals tend to have a very low voltage level. For these types of signals, amplification is required before they can be digitized properly. The best example of these signals is thermocouple signals. Some of the other sensors such as accelerometer, strain gauges, and resistance temperature detector cannot work until the excitation to operate is not completed. All these technologies are the best example of signal conditioning.

Because of its importance, we can say that signal conditional can be considered as the fundamental block of modern data acquisitions taken in consideration during the PCB design step. Physical measurement is the end goal of the data acquisition system. The following basic components are achieved by the signal conditioning process:

• Analog to digital convertor
• Sensor
• Signal conditioning
• Computer with DAQ

Use Of signal conditioning:

As discussed before, the basic task of signal conditioning is the conversion of the signal. The signals are converted from the input form to the output form. Most commonly, the input signals are of the electric type. Now why the conversion is required. This conversion is needed when the conventional signals cannot process the actual signal easily and it needs to be converted so that interpretation can be done correctly.

Frequency, electric charge, AC voltage, electric current, DC voltage, and current are basic signals that are accepted by the signal conditioning process.

A data acquisition system cannot work until it is connected to several signals and a wide variety of sensors. The arranged process is happened for the signal converting. The analog signal is taken by the signal conditioner for better manipulation. Once the signal is manipulated, it is then sent to the analog to digital converter system. The analog to the digital converted system is the end resource and it helps in digitizing the signal so it can be used in further processing. The basic purpose of the signal conditioning business is the conversion from analog to digital signals.

The digital domain is achieved by this process and this domain is then represented, displayed, stored, and analyzed. Input can be measured from a sensor that is used to measure strain, temperature, resistance, and acceleration. Moreover, the input can also be achieved by relays, switches, encoders, and clocks. A huge number of varieties can be interpreted from signal conditioners, this variety of signals include the output type.

There are some basic functionalities of the signal conditioning process. We will see the functionalities later. First, we need to understand the process of signal conditioning after the Printed Circuit board Fabrication is done.

Process of signal conditioning:

Following are the steps that are included in the signal conditioning process. The detail of every step is given for better understanding.

Step 1: Adjustment of a signal according to noise ratio:
The signal is adjusted to the noise ratio with the help of amplification and attenuation. In the electronic dictionary, you can say that amplification and attenuation are two opposite subjects. The deterioration of analog signals happens because of the background noise in the transmission process.

There comes the term signal-to-noise ratio. This means the signal strength ratio to unwanted background interference. This ratio is then increased with the help of amplification by magnifying the voltage level of the input signal. For example, in amplification, a signal of 0-1mv is converted into 0-10v.

On the other hand, in the attenuation process, the input amplitude is decreased. This process is done so that the signal can be fit in the optimal range of the device digitizer.

Step 2: removal of voltage signal for the prevention of equipment from damage:
The filtration and isolation of the input signal are required by the signal conditioning process. This is done because the unwanted background noise that is unwanted needs to be removed. Moreover, the removal of voltage signals that are far beyond the in-line digitizer is also compulsory.

There is a considerable difference in filtering and isolating processes. The filtering is done when noise needs to be rejected from a predefined frequency range. We can say that the isolation process is somehow similar. But the difference is a protection step of data acquisition and control system form the from voltage spikes is done. These voltage spikes can damage the entire data acquisition system.

Step 3: using controlled current or voltage for excitation technique:
Transducers and their subtypes require the excitation process. The operation of an active sensor is done with the help of the external sensor. A few types of signals that require external power to proceed further are strain gauges, accelerometers, transmitters, resistors, thermistors, and RTDs.

Step 4: signal linearization
Sometimes a signal cannot exhibit a linear relationship to the actual measurement. These types of signals can also be produced by some sensor equipment. To overcome this problem, we need a linearization process. As clear from the name linearization is done to optimize this signal according to the actual measurement.

The voltage of the input signal is mapped with the corresponding value requirement by physical measurement. Linearization is a very common signal connection process. The most important use of linearization is in industrial temperature measurement.

Now you have understood the process of signal conditioning in depth. Above mentioned steps need to be followed step by step for better signal conversion. Now it is necessary to understand the basic function of signal conditioning. How it is done and what are the benefits of signal conditioning.

Let’s understand the functionality and the benefits of this process now.

Functions of signal conditioners:

As we have discussed before, the main functions of signal conditioners are filtering, isolation and amplification. If these steps are not done correctly then inefficiencies and inaccuracy can happen. These can lead to incorrect output, loss of data, and other problems. So, the question arises how you can avoid these problems?

Now how would you know which type of signal conditioning is best for you? Well, the type of input signal you are going to use for processing will decide this. The other factors that make an impact on the type of signal conditioning process are desired type of output, available power for isolation in the quality criteria of the signal.

Now let’s understand the basic PC BOARD functions such as accuracy, flexibility, and the isolation required by signal conditioning.

Accuracy:

Accuracy is the main thing to be noticed in the signal conditioning process. There is a broad variety of accuracy along with signal conditioning. There is a direct relation of accuracy between the conditioner and the accuracy of the other equipment. For example, the sensor that is used to provide the signal. An extremely accurate signal conditioner cannot perform well if the sensor is used in the process is not precise and working correctly. So, in a nutshell, you can say that to get the highly correct and efficient output, every degree of accuracy should be the same in the signal conditioner and other parts of the system. Otherwise, the device and cost would be wasted with a high level of precision.

Flexibility:

As clear from the name flexibility in the signal conditioner means processing with a number of signals. A wider range of signal types can be processed with the flexibility feature. It is often considered as an additional advantage. Many designers and manufacturers add this feature to the product just to increase its functionality and efficiency.

Because if the device is dealing with a wide range of signals, it is likely to be more precise and calibrated for sensors. The replacement and change of other important parts of the system can be done with the help of flexibility. This will not affect the other part of the system.

Isolation:

Isolation is used in the signal conditioning process at more than one point. As a clear from the name, this process isolates the components and encourages that there is no interconnection between electric and other parts of the devices. The isolation process is required because it will enhance the common quality of the system. Moreover, the signal that needs to be isolated would also be decided according to configuration.
Should you have any further questions regarding the Signal Conditioning Process, feel free to contact us at sales@pnconline.com

PNC is providing a Turnkey solution to all your SMT assembly and bare board requirements across the United States.

Circuit Board Fabrication of Metal Core PCB’s

Circuit Board Fabrication of Metal Core PCB’s

The circuits boards composed of metallic cores is known as a metals PCB’s, and it is commonly utilized in LED devices. Metal Core PCB is harder to manufacture than FR-4 and can be more costly. Metal Core PCB (MCPCB) or Insulated Metal Substrate (IMS PCB) would be a technique created to address the FR4 substance’s thermodynamic constraints. If your boards must operate in a high-temperature condition, Metallic Core is a stronger option than FR4. Insulation Metal Substrate uses a unique insulator with a higher thermally conductance to offer electrically isolated among the copper and the metals cores.

Metal Core PCB Manufacturing is the process of designing and fabricating printed circuit boards (PCBs) with a metals core to be used with LED-based Solid States Illumination as well as other technologies that requires energy dispersion. Because adaptive elements could cause hotspots on an FR4 Printed Circuit Board, another type of cooling is required to ensure acceptable working conditions. Thermal vias underlying heat-generating elements (energy sources) can be used to transmit heat from the element (upper surface) to the base PCB layer, where it could be dissipated by a heat sink.

Manufacturing of Metal Core PCBs

Metal Core PCB Manufacturing offers a slew of advantages for a wide range of purposes. Because MCPCBs feature dielectric polymers layers as well as higher thermally conductance levels, they could attain a low heat resistance. Metal Core PCB Manufacture results in a solution that can transmit heat 9 times faster than a standard FR4 PCB. The laminates of MCPCBs disperse heat, ensuring that heat-generating aspects stay cooler. As a result, such elements have a longer working life and better efficiency.

The metal cores must first be drilled to enable layers transitions avoiding causing a short circuit in multilayered dielectric stacks. To begin, slightly larger holes are drilled into the metallic surface, which are then filled with insulation gel. The gel will be cured and solidified, allowing it to be plated with copper in the same way as a normal via can. The remainder of the stack is compressed and joined to the metallic surface, and then through-holes are machined in the stack up, which is then plated and cleaned.

Due to the existence of a metallic surface in the stack-up, metal-core PCBs should follow a specific method. If the circuit is a single-layer board with no layers transitioning back to a metal frame, the normal FR4 Circuit board fabrication procedure of pressing and bonding the insulating surface to the metal cores could be employed.

Purposes of Manufacturing of Metal Core PCBs

Metal Core PCB Manufacturing has a plethora of new uses as a result of the acceptance of new technology. This technique is effective for situations in which elements create a lot of heat and can’t be chilled utilizing traditional fans or other cooling techniques. MCPCBs are used in Solid States Lighting to assist achieve a higher level of luminosity with few LEDs.

Despite the numerous benefits of LED-based Solid State Lighting technology, they emit considerable quantities of heat. As a result, Metal Core PCB Manufacturing is beneficial for purposes such as:
● Automobiles Lights Fixtures in Basic
● Converters of energy (mechanical, telecom, energy accumulations, and great charge controls)
● Photovoltaic
● Security on the Street (brightness, streetlights, etc.)

Advantages of Metal Core Printed Circuits Boards

Metal cores PCBs have several capabilities over ordinary core components, including the capability to use a dielectric polymer with a high thermally conductance for decreased thermally impedance. A metal core PC Board can transport sound up to 9 times quicker than a normal FR4 lamination. The core materials used by MCPBC are great at dissipating heat and preserving essential heat-generating equipment cold, which can improve effectiveness, productivity, and lifespan. Benefits of Backlighting, the insulating impact of an iron core metal PCB, the brittle ceramic substance is replaced, suitable for putting on the wall, decreases labor and operational costs, and enhances product high thermal stability and structural qualities by replacing elements such as the heat sink all are the benefits of using Metal Core Printed Circuits Boards.

Whenever the energy from an LED was never adequately dissipated, problems happen; an LED’s lighting production is diminished, as well as degeneration when the heating stays stagnant in the LED packages. The goal of an MCPCB would be to effectively evacuate energy from across all current integrated circuits (not just LEDs). Among the ICs and the heating element, the aluminum bottom and thermal conducting insulating layers operate as bridging. Numerous heat sinks on top of surface-mounted equipment are eliminated since one singular heat sink was installed immediately to the metal foundation.

The fundamental feature of the materials is thermally expansions and contracting; nevertheless, various CTEs have varying thermal expansions. Aluminum and copper offer distinct advantages over standard FR4 in terms of thermal conductance, which can be as high as 0.83.0 W/c. The dimensions of a metal-based PCB are steadier than insulator substances in terms of directional durability. When aluminum PCB and aluminum sandwiches boards were heated from 30 °C to 140 °C, the size changed by 2.5 to 3.0%.

Thermal transmission is ten times faster than with a traditional stiff FR4 PCB. Heat dispersion is far preferable to that of ordinary FR4 structures. Increase power density could be achieved whereas equipment remains cool, extending element life and resilience. Dielectrics can be customized to meet your thermally and insulating needs. Systems with efficient cooling qualities can be driven harsher or de-rated for lower-cost materials.

It is possible to obtain the simplicity of both a heating sink and a PCB. That ensures you have not only the thermal properties of a heating element but also a PCB layout that is both cost-effective and small. This always allows for quick heat clearance from Led technology to avoid burns. By combining a dielectric polymeric covering with high thermal conductance levels, a decreased thermally resistivity could be achieved. The heat is dissipated by the laminates in the MCPCB, providing optimal heat managing and, as a result, longer operational life and improved productivity.

Metals PCB Layout and Variations

Aluminum cores PCBs, Copper cores PCBs, and Iron cores PCBs were the 3 types of metals PCBs now available on the marketplace, with Aluminium core PCBs being the most useful. The following is a common metal pcb fabrication.

1. Metallic Base

A metal-based PCB (MPCB) is made up of metallic substrates (such as aluminum, copper, or stainless), thermally conductive insulating, and copper circuits. MPCBs were employed in a wide range of industries because of their exceptional heat dispersion. They’re commonly found in power supplies, LED lights, and other places where heat is a significant problem.

2. Dielectric

The dielectric overlay is laminated along with a copper layer on the surfaces on an anodized, protected metals foundation. It is normally 50-200um thick and serves as an insulated covering. This could work as an insulating to avoid short-circuiting with the basis of the metal if it is too thick, and that will reduce heat dispersion. This could disperse heat efficiently if it is too thin, but it is simple to short-circuit.

3. Copper

To boost peeling resistance, the backside of the copper foil is chemically oxidized, and the surfaces were galvanized and brass plating. Copper was generally 0.5/1.0oz-in mass.

Why is it necessary to utilize a metals PCB?

Dissipation of Energy

Most double-sided and multi-layer PCBs were currently high-density, high-power boards with poor heat dissipation. Conventional platforms, including FR4 and CEM3, have poor heating conductivity because they are enclosed among levels, and heat could not be dispersed, resulting in a high-temperature breakdown of the components. Protected metals substances, which have a heat dispersion capability 5-10 times that of FR4, could address this issue.

Expansion Due to Heat

Resin, reinforcement materials (such as glass fiber), and copper foil make up traditional printable circuits boards. In the Z-axis dimension, the thermal expansion coefficient (CTE) of the substrates, whereas the CTE of copper, implying that the CTE of the metalized hole walls and the insulation ceiling of a typical Printed Circuit Board are vastly different. If the produced energy is not removed promptly, thermally expansions and contractions would shatter the metalized holes, resulting in faulty electronic devices.

That issue is exacerbated by SMT (Interface Mounting Technologies). Because the contact is made by solder directly across the metallic pads and the SMD, the CTE differential among the ceramics chips and the FR4 substrates was likely to induce connections fracturing over time. The metals PCB could efficiently control the thermal transfer issue, reducing thermal expansions and contracting and enhancing the electronics equipment’s lifetime and dependability.

Stabilization in Dimensions

In terms of dimensions, a metal PCB is far more dependable than a regular PCB. For instance, the dimension variation of an aluminum core metals PCB heated from 30°C to 140°C is 2.53%. High heat dissipating substances protect parts from overheating and damages, and a metals cores PCB or an aluminum cores PCB may be the best option because it effectively works as one giant heat sink.

Interested to know more about Metal Core PCB boards, or PC Board Assembly contact us at sales@pnconline.com.

RF Microwave PC Board Applications

RF Microwave PC Board Applications

There are numerous uncertainty in RF (radio frequency) PCB (printed circuit board) designs. Whenever it comes to circuits with frequencies below microwave (particularly low intermediate frequencies digital logic circuits), however, careful design is the only way to ensure first-time circuits designing effectiveness while mastering all design concepts.

Plated-through hole (PTH) has been used to connect traces on various layers simultaneously, and resistance is frequently integrated inside the layer stacking or generated by selectively laying down resistant material. Most of the needed electronic systems are usually put on the top and bottom layers, with interconnections created among parts and traces using soldering or wire bonding. The microwave efficiency, as well as the physical behavior in the predicted surroundings, is heavily influenced by the structure of the underlying layers.

Nevertheless, 2 to 3 PCB variants can ensure circuit reliability at frequencies beyond microwaves and high-frequency PC-level digital logic circuits. Nevertheless, at frequencies above microwaves, more generations of PCB design are required for continuous improvement in RF circuits. As a result, various challenges are almost expected to arise along with the process of RF circuit design.

RF Layout Concept

The preceding broad principles should be followed while designing an RF layout:

● As often as feasible, high power amplifiers (HPAs) and low noise amplifiers (LNAs) must be separate. High-frequency RF transmitting circuits were separated from low-frequency RF receiver circuits by a large distance.
● On the high-frequency portion of the PCB boards, at least a detailed ground must be accessible, and through-hole must be avoided. The more copper foil surface area there is, the better.
● Circuit and electricity are both affected by decoupled in the same way.
● The distance between the RF output and the RF input must be as large as possible.

Those circuit boards are made to work at moderate and incredibly high frequencies (megahertz and gigahertz). They should be made out of high-quality materials. Here are a few of them:

● FEP
● LCP
● RO laminates are made by Rogers.
● FR-4 High-Performance
● Hydrocarbons loaded with ceramics
● Woven or tiny glass fibers in PTFE

Particular properties of materials include a low optical tangential, a low dielectric (Er), and outstanding Coefficients of Thermal Expansion (CTE).

PCB Requirements for RF Radio Frequency

The RF PCBs have dielectric thicknesses of 0.1 to 3.5mm and are available in copper with weights ranging from 0.5oz to 15oz with UL certifications of 80z. With a minimum line width and spacing of 0.075mm, they have a thermal capability of 0.82 W/mK.

It can build the best-fit solutions for your important RF electronics product using our comprehensive understanding of accessible RF substrates, driven product development, and long-term product sustainability.

Purity PCB could assure that all price objectives and budget were reached through early coordination, future ensuring your RF board products to the least potential price point, with a proactive and challenging attitude to costs monitoring.

Purity delivers the degree of reliability, reproducibility, and affordability to bring any RF Microwave Printed Circuit Board demand to fulfillment, from one-off prototype needs to producing a manufacturing suite of products.

Framework and Methodology of RF Circuit Design

Higher – frequency Printed Wiring Boards are required for applications such as network and communication (PCBs). Whenever these organizations approach PCB makers for a solution, the manufacturers typically suggest Radio Frequency (RF) or microwaves PCBs. PCB makers recommend these PCB assemblies for information and telecommunication application for a variety of reasons. Let’s have a glance at certain fundamentals.

Physical segmentation and electronics separating are two types of partitioning. The first is primarily involved with the part arrangement, orientation, and shields, whilst it is divided into power systems, RF routes, sensitivity circuitry, signaling, and ground partition.

A. Concept of Physical Partitioning

The principle of element design:

Components design is critical to achieving a successful RF system. The most efficient method is to first fix parts along the RF line and have their orientation changed so the RF route may be minimized with input far enough from outputs and low – and high circuitry segregated as much as feasible.

The principle of PCB laminating

A most effective method of Circuit board fabrication is to place the primary surface on the two layers beneath the first planes and the RF traces on the first layer. The diameter of the RF route via holes must be limited.

The idea of RF tracking and RF parts

The design of RF tracking and RF parts Linear circuitry such as multi-stage amplifiers can separate all RF regions within the physical environment, but duplexers, mixers, and mid-frequency amplifier/mixers frequently cause mutual interfering among several RF/IF channels. As a result, this form of influence should be avoided at all costs. Crossing RF/IF traces and leaving a grounding around them is recommended. The proper RF routing is critical to PCB efficiency, hence why components layout takes up the majority of the design effort in cell phones.

B. Principles of Electronics Partitioning

The concept of transmitting power:

Because the DC in most mobile phone circuits is usually relatively low, tracing width isn’t an issue. Tracing with a high flow and as broad a breadth as feasible, on the other hand, should be constructed separately again for energy availability of quality amplifier to keep transmission voltage to a minimal. Numerous through apertures must be used to transmit energy from one plane to the other to prevent massive power losses.

High-power systems’ energy decoupling:

If perfect couplings at the supply pins of a high-power amplifier are not accomplished, high-power noises would be emitted throughout the boards, causing numerous problems. Grounding is critical for high-power amplifiers, and a metal shielding covering is frequently required in their designs.

The concept of RF input/output separation:

For most cases, it also is critical to ensure that RF outputs are far from RF inputs, this applies to amplifiers, bumpers, and filters. In the worst-case scenario, self-excited vibrations may result if the amplifiers and bumpers inputs are restored to respective input terminals at an acceptable amplitude and phase. In ideal circumstances, they would be able to perform reliably at any voltage and temperature. In reality, they could become unstable, causing noise and interference signals to be added to RF transmissions.

Overall, because of its spread variable circuits, RF circuits have skin impact and coupler impact, which distinguishes them from low-frequency circuits and DC. As a consequence, the difficulties highlighted above should be given extra attention during the designing of RF circuit PCBs to ensure that the circuit is both precise and efficient.

Advantages of RF Microwave PCB Applications

Along with its multiple evident advantages, RF PCB has seen the quickest development. The following are a few of the numerous advantages:

Quick operating ability:

Because RF PCBs operate at such a high frequency, they can effectively provide the signals in the circuits in a short period. The total gadget can work faster than ever before due to the obvious quickest connectivity among the materials due to speedy information transit. As a result, smartphones, aeronautical devices, and other RF PCB products can operate in a matter of seconds.

Multi-layered board:

RF PCBs can be used in circuits with various layers based on the stack-up from the PC Board manufacturer. This ability to stake out allows people to work at their best. Multi-layered circuits have high densities that allow them to fit into a tiny device. It also minimizes the circuit’s likely weight and making it more convenient to use.

Cost-effective:

Several layers The PCB kind of RF is a significant influence in lowering the circuit’s costs. The price of the circuits constantly decreases as the weight and size of the circuits decreases.

Pitching element placement:

The finer-pitched materials of the circuits may be easily placed just on RF PCB due to its sophistication. This is critical to remember while beginning the process.

Strong Sensitivity Strength:

Among all the positive aspects of the RF PCB, its high-temperature stress endurance energy is overlooked. It’s a boon for industries that work in high-temperature conditions. Any regular PCB would fail to work in such a hot environment as found in the army, airline, and automotive sectors, but RF PCB, with its extreme sensitivity capability, is just like a ray of sunshine in those domains.

At PNC, you can get your RF microwave design or PCB Assembly requirements fulfilled. Just Email us at sales@pnconline.com.

Minimizing Crosstalk in PC Board Layout

Minimizing Crosstalk in PC Board Layout

In this ongoing series on PCB layout from the design team at PNC, previous posts have looked at some of the initial steps to turn a circuit schematic into a manufacturable, reliable PCB. These posts have looked at  component placement, selecting appropriate trace widths, and BGA routing.   In this post we are going to take a deeper dive into methods for reducing crosstalk in the PCB design. After the power and ground have been routed, the next task is to route high speed signal traces, and the traces that could either generate or receive crosstalk.

 What is Crosstalk?

Crosstalk occurs when the signal on an aggressor trace on a PCB appears on a nearby victim trace, due to capacitive and inductive coupling between the two traces.  Typical aggressor signal traces are:

● High speed digital signals, especially clock signals
● Noise from switching power suppliers
● High frequency RF.

Victim signal traces, on the other hand, carry high impedance signals like op amp input lines or reset lines, or low impedance signals with long loops.   Low amplitude signals such as a sensitive analog measuring circuit traces are also susceptible.

Crosstalk occurs when aggressor trace and victim trace are close together and run in parallel for a distance.  The aggressor and victim(s) can be side to side on the same layer or on top of each other on adjacent signal layers. Coupling between traces on adjacent layers separated by just a thin section of laminate is called broadside coupling.

Minimizing Crosstalk in PC Board Layout
Minimizing Crosstalk in PC Board Layout

 

 

 

 

 

Printed Circuit Board Design guidelines to reduce crosstalk

There are several design rules to reduce crosstalk between signal traces.  Before applying these rules, the first step is to use the general guidelines described above to identify and flag any potential aggressor signal traces and their potential victims.

Since crosstalk occurs between two traces running in parallel, try to reduce the distance that the aggressor and victim traces run in parallel. Unfortunately, this may be difficult if the signals originate and terminate from the same locations.  To minimize broadside coupling try to orient the signal traces east-west on one layer and north-south on the second layer.

It is essential to have a broad contiguous ground plane directly under (or over) the signal layer.  A ground plane located between two signal layers can prevent broadside coupling. However, make sure that ground planes located on adjacent layers but not electrically connected do not overlap.  The overlapping ground planes separated by a dielectric form a capacitor, which can transmit noise from one ground plane to the other. This can defeat the purpose of separate ground planes if they were created to isolate the noisy elements of a circuit from the noise sensitive ones.

Increasing trce spacing

The most effective method of reducing crosstalk is to increase the spacing between the aggressor signal trace and the potential victim traces.  Like all electromagnetic radiation, electrical or magnetic coupling between the two traces drops with the square of the distance between them.  The amount of spacing required between the traces is dependent on the height of the traces above the ground plane.   The formula defining this relationship is from Douglas Brooks “Crosstalk Coupling: Single-Ended vs. Differential”   The coupling between two traces is proportional to:

Where S is the spacing between traces, and H is the distance from the trace to the ground plane.  Once H is defined by the lamination stack-up, the relative change in coupling can be easily plotted as a function of S.  Douglas Brooks looks in detail at the coupling between traces under several scenarios.  For those looking for some general guidance, a spacing of 5H is considered conservative.  The PC Board design team at PNC can assist designing a PCB stack up that will minimize the spacing needed between coupled traces, ensuring that crosstalk is minimized while maintaining routing density.

Finally, for very high speed digital signal traces, consider the use of differential pairs.  For many designers, the most common applications for a differential pair is for a high speed serial bus like USB, SATA, or HDMI.  The design rules for the layout of differential traces is beyond the scope of this post.

The most important part of reducing crosstalk in your PCB design is to first recognize in which signal traces crosstalk is likely to occur, then follow the guidelines above to minimize it.  PNC’s Printed Circuit Board designers have experience with high speed digital and RF circuits and can help you select the correct PCB layer stack-up and review your designs for areas where crosstalk is likely and suggest ways to minimize it. Request a design review from PNC today

Beyond PCB Assembly Services, Board Support Package Development

Beyond PCB Assembly Services, Board Support Package Development

What is a Board Support Package?

A board support package (BSP) is a collection of essential low level software applications configured for a specific microprocessor and its associated hardware. It supplies the drivers for all the hardware in the system andcontainsa bootloader to initialize the microprocessor and hardware prior to loading the operating system. The package may contain additional low level software to assist the developer in initializing the operating system. The BSP can also include a root file system, and a utility to configure the microprocessor and other hardware.By using PNC to develop the BSP, it will allow them to design around their circuit board fabrication capabilities and process.

Board Support Packages are specific to a family of microprocessors and to a specific operating system.  A typical BSP may contain drivers and initialization code for:

  • Initializing the microprocessor
  • The parallel and serial buses
  • The volatile and nonvolatile memory
  • The display and graphics card,
  • Digital and analog I/O
  • Camera, wireless modules, user input devices etc.

While a BSP for the hardware is the first requirement for developing a product with embedded software, this doesn’t mean that every company developing embedded software needs to develop their own BSP with the drivers for their specific hardware configuration. There are five reasons to let an outside BSP developer like PNC develop the BSP for your embedded application.

1. The BSP supplied by the microprocessor manufacture is an incomplete solution

The microprocessor manufacturer will typically supply a rudimentary BSP with their evaluation board.   This is because manufacturers know that making it easier for the developer to work with the microprocessor is helpful to being selected for the final design and pcb assembly process.   However, the manufacturer’s BSP may not have the drivers for the specific hardware in your design – the only way to ensure a BSP fully supports your hardware design is to have it customized for you.

2. Developing device drivers is a specialized skill

Developing the drivers and initialization code BSP requires detailed knowledge of the microprocessor and its peripheral hardware.  Most developers writing applications running on an OS do not have the requisite expertise to write the hardware driversunderneath that OS.  On the other hand, a group focused only on BSP development like the team at PNC obtains that expertise by working with many hardware platforms every year, and by developing robust tested reference code for common peripherals such as displays and USB ports.

3. A BSP is needed only once for a product

A BSP is needed near the beginning of an embedded software product to allow the developers to work with the target hardware instead of an evaluation PC board or emulation software. Once all drivers are debugged, however, the BSP rarely needs to be touched again except for occasional updates to address hardware end-of-life issues.  This is different than the product’s application, which may see multiple releases over the life of the product.  Since BSP updates are so infrequent it does not make sense for an organization to maintain that highly specialized expertise for the months or years between BSP updates.

4. The BSP and associated drivers are invisible to the customer

Application software that meets customer needs is a close collaboration between developers, product management, marketing, and sales.  Any time spent by the in-house team developing a BSP is time not spent developing features the customer will see and use.  Outsourcing the invisible aspects of the product like the BSP allows the development team to stay focused on the customer.

5. Outsourcing the BSP can accelerate product development

Handing off the BSP to an outside supplier like PNC means that the team’s developers are not tied down developing it internally.  The BSP supplier can develop the BSP incrementally starting with core functionality followed by drivers for some of the less critical hardware once the development team is ready for it.  The outside supplier also brings deep expertise to the driver development, meaning driver development takes less time, and works the first time. The most beneficial reason for PNC to develop your BSP is that they can also fabricate PCB’s as well having in house pcb assembly services.

Talk to the software team at PNC the next time you have a time critical embedded project.  Let PNC help you with your Board Support Package, device drivers, operating systems porting, or protocol stacks development.