What Is High-speed PCB ?
High-speed refers to a printed circuit board that has a high signal count and layer count. These PCBs are often equipped with processor speeds and DDR signals.
What Is the Difference Between High-speed and High-frequency (HF) PCBs?
● The low thermal expansion of HF PCBs makes them ideal for high-tech, high-density interconnects. Thus, They play a significant role in high-speed communications and RF microwave technology.
● High-speed PCBs can be used in a variety of applications such as computers, phones, Internet routers and power amplifiers.
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 projects aim to deliver products on time and, if possible, successfully within a short period of time. High-speed PCBs should be manufactured by an experienced manufacturer that provides design for manufacturing excellence (DFM) and DFX. JarnisTech is a one-stop high-speed PCB manufacturer with 20 years of experience and provides free one-on-one engineering support for high-speed/high-frequency PCB projects.
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
People often mistakenly believe that High-Speed PCB or High-Frequency PCB are the same things when in reality, they mean something completely different.
● High speed refers to digital technology which transmits data at an extremely high rate. Usually, this is related to 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 used to generate pulses that allow digital information transmission. A sine wave is an RF waveform. A combination of several sine waves at different frequencies can create a squarewave, which can then generate 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 sorted according to a frequency at the fundamental frequency (1GHz). Three times harmonic (3GHz), five times harmonic (5GHz), and seven times harmonic (7GHz) are the fundamental frequencies.
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 ?
Is There High-speed Interface on Your PCB Board
It is easy to determine if high speed design guidelines are necessary by checking if your interfaces support high speeds, such as DDR, PCI, PCI-e or video interfaces like DVI and HDMI.
These interfaces require you to adhere to some design guidelines. You should also provide the exact specifications for each data in your documentation.
Ratio Of Trace Length To Signal Wavelength
In general, if the message wavelength is the same length as the trace length, then your PCB will need a high-speed design. Adaptions to the DDR standard require traces to have a length that matches minimal tolerances.
In general, if your trace length and wavelength are within an order of magnitude of one another, You’d better also check high-speed designs.
PCB With Wireless Interfaces
As we know that each PCB contains an antenna. It must design for high-speed signals regardless of whether the connector is on the board or through it. Additionally, onboard antennas must be close in impedance so that they can match tune lengths.
A circuit board with SMA connectors or similar connectors must connect to connectors that have a specific impedance.
Why Design Is Important in High-speed PCB ?
To put it simply, high-speed PCB design rules should be followed if you want a PCB to work correctly. To make sure your engineer understands your needs, here are some questions you should ask:
● 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 answer could be either 90 ohms or 100 ohms. Or it could be 120 ohms. Depending on the impedance, there are specific rules that you need to follow.
● The location of the PCB is important. It is important to remember that using a high-speed PCB too close to a power line or a noisy circuit section may result in interference and poor signal quality.
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.
Planning Your High-speed PCB-stackup and Impedance
You can by creating a PCB stackup, it can help you determine the impedance and ease of routing for high-speed circuit boards. Each PCB stack up includes a set of layers that are dedicated to high-speed signals and power planes.
When assigning layers to a stackup, you have to think about the following factor:
Board Size and Net Count
In the PCB layout, how many nets should you route based on the size of the board? If the board is physically larger, you may find that there is enough room to route throughout the PCB layout without adding too many signal layers.
You may not have a lot of room for routing around the surface layer in the case of high net counts and constrained board sizes. Therefore, When traces are placed closer together, you will need to have more internal signal layers. At the same time, If we use a smaller board size can force improve routing density.
Number of Interfaces
Sometimes, it is a good strategy not to route more than one interface per layer. This depends on the width of your bus (series or parallel) as well as the board size. By keeping all signals on the same layer of the high-speed digital interface, all signals will see the same impedance and skew.
Low Speed and RF Signals
Does your digital design contain any RF or low-speed digital signals? If so, these components could take up surface layer space that could be used for high-speed components or a bus, so an additional internal layer may be required.
To ensure power integrity, use a large power plane and ground plane for each voltage level you need in your large integrated circuits. Additionally, they must be placed on adjacent layers to ensure there is a high plane capacitance to support stable power with decoupling capacitors.
High-speed PCBs can be found in nearly every industry we come across in our day-to-day lives. The following are some of the applications and industries we have worked with on high-speed digital PCBs:
● Network communications for signal integrity verification.
● For elements requiring an impedance control of high order, such as radios, small-factor layout and design.
● Installed electronics that are consumer-facing, such as ATMs, need to be maintained according to the latest standards, They have high volumes and require a short time-to-market.
● Digital high-speed test boards for different signals, including testing for RF signal roll-off.
● Individual PCBs for medical equipment that requires extremely dense, high-speed, but low in cost.
Working With JarnisTech
Furthermore, we are committed to reducing signal integrity issues in PCB designs, as well as offering you an unprecedented level of service and flexibility.
By the way, it doesn’t matter how many your order is, and even if you’re asking for 1PCS PCB board, JarnisTech will provide you with excellent engineering support and on-time delivery. Now, please contact us as soon as possible by Telephone(0086-0075-23034656) or email([email protected]), we will provide competitive prices and professional engineering technical support for your high Speed PCB project or other type PCB.