In the evolving world of electronics it is essential to develop efficient and reliable high speed Printed Circuit Boards (PCBs). Leading with technological advancement, high-speed PCBs enable the flawless execution of intricate and speed-demanding applications. From telecommunications to progressive computing, these PCBs foster the rapid conveyance of signals, ensuring optimum performance of devices. The goal of this composition is to explore the fundamental principles, obstacles, and revolutions shaping high-speed PCB design’s vista, offering a perspective into the precise deliberations involved in their formation.
High-speed PCB
Not all printed circuit boards that operate with digital signals must necessarily be considered High Speed PCBs. It is often sufficient to adhere to the conventions and rules governing the layout definition in many cases.
● In addition to positioning and ordering electronic components, power and ground planes must be defined, vias must be added, and tracks must be manually routed or automatically routed.
● A PCB that is used for high-frequency signals requires a precise and specific design. This will ensure signal integrity under all conditions.
● It is for this reason that manufacturers of high density and high frequency components (FPGAs, GPUs, SoCs, and RF modules) design and manufacture their own product evaluation boards.
A PCB is considered “High Speed” when signal switching occurs at frequencies between megahertz and gigahertz. These cases require the adoption of specific rules for PCB design. These rules are common to all types of printed circuit boards：
● Contain the noise from the power distribution network (especially when switching power supplies are present);
● Reduce crosstalk phenomena between adjacent tracks. Capacitive crosstalk phenomena can easily be generated when the signal frequency is high. This happens because the induced currents have a capacitive impedance;
● Reduce the bounce of ground reference (ground bounce) and its effects. These effects are directly related to signal integrity issues and can be reduced by properly defining the PCB stackup, and decoupling all the parts of the board (for example, the separation between analogue and logic areas).
● Ensure that you get the best impedance match.
● Eliminating transient ringing caused by too-narrow tracks.
● For each signal line, provide the correct termination. As a result of this aspect, together with the control of input, load, and transmission impedances, the signal reflection is eliminated.
● High degree of immunity to electromagnetic interference (EMI), both conducted and radiated.
Why Choose Us?
These reasons make JarnisTech a reliable high-speed PCB manufacturer:
One-stop Solution for High-speed PCB Projects
High-speed PCB initiatives intend to maintain punctuality in product delivery, striving to accomplish success within a minimal timeframe whenever feasible. The manufacture of high-speed PCBs necessitates an adept manufacturer that offers superior design for manufacturing (DFM) as well as DFX. At JarnisTech, we serve as an all-encompassing high-speed PCB manufacturer, enriched by two decades of experience, along with complimentary one-on-one engineering assistance for high-speed/high-frequency PCB ventures.
Capability oF Fabrication High-speed PCB
● Make sure to check high-speed PCB designs prior to quoting. If there are any problems, we will offer free suggestions.
● One-stop manufacturing solutions, including free DFM and DFX for high-speed PCB projects.
● Grasp the core technologies for high-speed PCB manufacturing, such as impedance control, embedded antenna DFM, expansion/contraction control, etc.
● We have many type of High speed PCB base materials in stock, and the storage period is within 45 days (Manufacturers who do not have storage typically take 1 to 2 months for base materials to be purchased.)
● Manufacture 4 to 32 layers of high-speed/high-frequency PCBs, such as RF 6 to 24GHz PCBs, RF 77GHz PCBs, and embedded antenna PCBs.
High-speed PCB vs High-frequency PCB
It’s a common misconception to interchangeably use High-Speed PCB and High-Frequency PCB, when in truth, they signify entirely diverse concepts.
● High speed pertains to digital technology that disseminates data at an exceptionally rapid pace, typically associated with the time domain.
● It is usually concerned with the radio frequency (RF) of the analog signal at high frequency moving energy. This is how electromagnetic waves react in a particular frequency range or range of frequencies, and it related to frequency.
Additionally, RF techniques and High-Speed Digital (HSD) signals share a fundamental connection. RF waveforms are employed to generate pulses that facilitate digital information conveyance. An expression of an RF waveform can be a sine wave. With a fusion of various sine waves at unique frequencies, a squarewave could be fashioned, which in turn can stimulate a pulse of an electronic signal.
For example, the clock speed of 2GB/s is made by RF signals at frequencies around 1GHZ, 3GHZ and 5GHz.. These signals are methodically curated according to their distinct frequencies. The principal frequencies encompass the triple harmonic (3GHz), the quintuple harmonic (5GHz), and the septuple harmonic (7GHz)
When designing a PCB at millimetre wave frequencies, the wavelengths associated with PCB design characteristics are important, and wavelength segments can affect circuit performance. It is possible to use a stripline PCB having a material DK of 3. This has a wavelength of approximately 0.100” (2.54mm at 70GHz). Waveform performance is affected when circuit characteristics exceed 1/2 wavelength. However, this effect can also be seen at 1/4 wavelength. The negative impact of this feature on waveform performance can be avoided if it is less than 1/8 wavelength. The physical dimension of the strip line that is associated with 1/8 wavelength at70GHz is 12.5mil (0.32mm). Any signal exceeding 1/8 wavelength can affect the performance of the 70GHz waveform. Simply getting energy from the connector could be problematic.
Wavelengths at millimeter-wave frequencies can have an impact on circuit performance. Material properties can also affect RF performance. It is common for PCBs used in high frequency applications to have woven glass reinforcement to increase the material mechanical stability.
Rogers series high-frequency material is a common high-frequency material. Click the link High Frequency PCB and Rogers PCB . High-speed materials that are commonly used include TU875, S7439, R5725, FR408HR and R5775 (M6).
How do Know If Your Design Needs to High Speed PCB?
Assessing the necessity for a high-speed Printed Circuit Board (PCB) in your design hinges on comprehending the electrical attributes and functional specifications of your circuit. The importance of high-speed PCB design is paramount for operations that run at elevated frequencies, possess rapid switching intervals, or demand meticulous signal accuracy. Outlined below are some significant markers and factors to assist in establishing whether your design should be classified as high-speed.
Operating Frequency: If your circuit operates at high frequencies, typically above a few hundred MHz, it’s likely you’ll need high-speed PCB design techniques. The exact frequency threshold can vary depending on the specific application and the definition of “high-speed” may shift as technology progresses.
Signal Ascend Time: The significance lies not solely in the operational frequency but also the signal’s ascend time. Swift ascend times (the duration required for a signal to transition from a low to a high state) can instigate high-speed impacts even within lower frequency systems. Should the ascend time fall below a quarter of the signal’s transit duration across the PCB, high-speed design aspects are deemed essential.
Signal Reliability Complications: Designs of a high-speed nature are prone to signal reliability complications such as reflections, crosstalk, and electromagnetic interference (EMI). When signal preservation is of prime importance for your application and you’re tackling swift data rates or sensitive signals, the employment of high-speed design methodologies can aid in the reduction of these problems.
Length of Electrical Paths: If the electrical path lengths approach or exceed half the wavelength of the highest frequency signal, your design may need high-speed consideration. At these lengths, traces can act as antennas or transmission lines, leading to potential issues with signal integrity.
Incorporation of High-Speed Interfaces: Supposing your design merges high-speed communication interfaces like USB 3.0, Gigabit Ethernet, PCIe, or DDR memory, adherence to high-speed PCB design fundamentals becomes requisite in order to guarantee dependable functionality.
Need for Impedance Control: High-speed designs often require controlled impedance traces to prevent signal reflections and losses. If your design demands specific impedance characteristics for signal lines, it’s a sign that you need to apply high-speed PCB design techniques.
Heat Control: Circuits of a high-speed nature can emanate considerable heat. Efficacious heat control is paramount, with high-speed design playing a vital role in this aspect through the optimization of component placement and PCB layout design to enhance heat dispersion.
Should your design display one or multiple of these features, it probably necessitates the utilization of high-speed PCB design methodologies. High-speed PCB design demands thoughtful deliberation of the layout, component positioning, signal direction, and layer stacking to guarantee the functionality and dependability of the circuit. It frequently calls for the application of specialized simulation software to anticipate and neutralize complications pertaining to signal integrity, power integrity, and electromagnetic compatibility.
Why Design is Important in High-speed PCB?
In essence, adherence to high-speed PCB design norms is essential for optimal PCB functionality. Ensuring your engineer comprehends your requirements, it is beneficial to pose the following inquiries:
● Is there a controlled impedance circuit on this board?
If differential pairs or signal-ended circuits exist, the answer will determine whether they are signal-ended or differential.
● What is the impedance at which controlled impedance circuits are operating?
The response might potentially be 90 ohms or 100 ohms. Alternatively, it could be 120 ohms. Depending on the particular impedance, there exist specific guidelines that necessitate adherence.
● The location of the PCB is important?
It’s crucial to keep in mind that the close proximity of a high-speed PCB to a power line or a turbulent circuit section could potentially cause disturbances and degrade the quality of the signal.
4 Tips in High Speed (>100MHz) High-density PCB Design
In the case of fixed circuit board sizes, if additional functions need to be accommodated in the design, it is often necessary to increase the track density of the PCB, but this may lead to increased mutual interference between tracks, and the track is too thin to make the impedance impossible to reduce. In addition, you should be aware to Crosstalk interference is a major factor in the design of high-speed, high-density PCB. It has a significant impact on timing as well as signal integrity. These are some caveats：
● Ensure the continuity and matching of the trace characteristic impedance.
● The trace space. It is commonly seen that the trace spacing is twice the line width. With simulation, we can determine if the trace spacing has an impact on timing and signal integrity, as well as find the minimum spacing that can be tolerated. These results can vary from one chip to the next. The appropriate termination method should be chosen. Since crosstalk between adjacent layers in the same layer is greater than that between adjacent layers within the same layer, so upper and lower adjacent layers should avoid the same running direction.
● To increase the area of the track, use blind/buried vias. The manufacturing cost for the PCB board will increase. Despite the difficulty of achieving full parallelism and equal length in the actual implementation, it is worth the effort.
● When differential termination and common-mode termination are used together, they mitigate the effects of differential termination and common-mode termination on timing and signal integrity.
How Plan Your High-speed PCB-stackup and Impedance?
Through developing a PCB stackup, it’s feasible to ascertain the impedance and simplify the routing process for high-speed circuit boards. Every PCB stackup comprises a designated set of layers orientated to high-speed signals and power planes.
When allocating layers to a stackup, the ensuing aspect demands thoughtful consideration:
Dimension of the Board and Network Quantity:
In the context of the PCB layout, what should the number of networks to route be, predicated on the scale of the board? If the board has considerable physical dimensions, you might deduce that there is adequate space to route across the PCB layout without necessitating a surplus of signal layers.
Routing Density:
With high net counts and confined board dimensions, you might find limited accommodation for routing around the surface layer. Consequently, when traces are configured in closer proximity, it necessitates a greater number of internal signal layers. Simultaneously, using a smaller board size can effectively enhance the routing density.
Quantity of Interfaces:
On occasion, a sound approach is to refrain from routing more than a single interface per layer. This is contingent on the breadth of your bus (be it series or parallel) as well as the size of the board. By maintaining all signals on a solitary layer of the high-speed digital interface, all signals will experience identical impedance and skew.
Low Velocity and RF Indications:
Dose your digital schematic incorporate any RF or low-velocity digital indications? If this is the case, these elements could occupy surface layer area that might be needed for high-velocity components or a bus, hence an extra internal layer could be necessitated.
Power Integrity:
To maintain power integrity, it is advisable to utilize a substantial power plane and ground plane for every voltage level required in your extensive integrated circuits. Furthermore, these need to be situated on adjoining layers to guarantee a high plane capacitance, thereby supporting stable power with decoupling capacitors.
Applications
High speed PCBs are widely used in industries that are part of our daily lives. Here are some examples of applications and sectors where we have shared our knowledge about speed digital PCBs：
● Verification of signal integrity within network communications.
● For components that necessitate advanced impedance control, like radios, small-factor layout and design is essential.
● Consumer-oriented embedded electronics, like ATMs, should adhere to up-to-date standards, they are high in volume and demand a brief time-to-market period.
● Distinct high-speed digital test boards for various signals, inclusive of RF signal roll-off testing.
● Specific PCBs for medical equipment, necessitating extreme density, high velocity, yet remaining economical in cost.
Summary
Working With JarnisTech
Furthermore our commitment lies in resolving integrity issues in PCB designs all while delivering unmatched service and flexibility to you.
Regardless of the size of your order, even a single PCB board request will be treated with exemplary engineering support and punctuality in delivery by JarnisTech. We encourage you to contact us promptly via telephone(0086-0075-23034656) or email([email protected]). We ensure competitive pricing and professional engineering technical support for your high-speed PCB project or any other type of PCB requirement.
