High-Speed Material Design Guide
The High-Speed Material Design Guide will help you choose a reliable and cost-effective dielectric material that best suits your design.
The Sierra Circuits High-Speed Material Design Guide will help you choose a reliable and cost-effective dielectric material that best suits your design.
With the advent of high-speed and HDI circuit boards, electronic devices have become more compact with a faster response rate. When it comes to high-speed boards, the risk of EMI, noise, and crosstalk is high. One of the effective ways to mitigate these challenges is by selecting a dielectric material that exhibits lower dielectric loss at high frequencies.
If you’re designing a high-profile PCB such as aerospace and industrial boards, you need to ensure that the dielectric material should sustain high temperature, humidity, and stress while operating in a harsh environment. To achieve this feat, you need to be aware of the material characteristics that matter. For instance, a low Dk material can be an ideal choice if you’re routing high-speed signals in your board. Similarly, if your PCB operates in a high-temperature environment, you need to choose a material with a suitable glass transition temperature and decomposition temperature.
In short, understanding the characteristics of the dielectric is crucial for fabricating a quality printed circuit board.
Materials for high-speed PCB designs
The material used in your stack-up has a significant impact on multiple aspects of PCB functionalities such as signal integrity, and thermal and mechanical stability. Thus, choosing the right substrate will help you evade crises during the PCB production process.
A variety of materials at different price ranges are available in the industry. The properties of these dielectrics vary depending on the manufacturer. However, there are a set of standard parameters like dielectric constant, dissipation factor, and CTE that define the material characteristics. Understanding these properties will help you interpret the values in the datasheets. In addition to this, you should also learn the constituents and the behavior of the substrate at higher frequencies.
Two primary factors that you need to consider when choosing materials for your high-speed designs are:
- Signal loss at the operating frequency
- Glass weave effect
The risk of signal attenuation increases as the operating frequency goes high. To tackle this challenge, you will have a choose dielectric material that offers uniform impedance. Here, the arrangement of the glass fiber plays an important role. It also determines the impedance characteristics. A tightly woven substrate features a higher resin content when compared to a loose weave material. Due to this, Dk and impedance remain constant throughout the material which is essential for signal integrity. Apart from this, you should also ensure a smooth copper dielectric interface to avoid propagation delay. A low-profile copper can be an ideal choice for high-speed designs.
To assist you in selecting the right PCB material for your high-speed design, we have developed a comprehensive design guide that includes all the necessary details.
Also inside this High-Speed Material Design Guide
- Role of substrates in high-speed designs
- Factors that affect the material selection
- Elements of PCB materials
- Popular high-speed substrates
- Effect of resin content and glass weave structure on your board