Launch vehicles and satellites rely on RF components to meet the objectives of their missions. It goes without saying that the mission will not succeed unless these components are carefully packaged and protected from the intense environmental factors presented in space. When it comes to packaging (mounting, connection, encapsulation, and reliability of semiconductor devices) RF components it’s essential that you select the right packaging type.
In the following blog we’ll share what packaging types are available and what approach to consider when planning your next package assembly project for space bound RF components.
What packaging types are available for my space bound RF components?
Based on formation, there are multiple ways to categorize packaging types for RF components. There are two main types of packaging; the through-hole mount packaging type (THM) and the surface mount packaging (SMT) type.
Through-Hole Mount Packages (THM)
Before the rise of surface mount packaging in the 1990’s, through-hole mounting (THM) was the predominant packaging approach used in the semiconductor industry. In the THM process component leads are placed into drilled holes on a bare printed circuit board. THM packages are offered in ceramic, metal, glass and plastic packaging types.
While it can be difficult to find THM components in the age of SMT packaging, this packaging type is still highly desirable for certain niche applications, primarily high-reliability defense and space.
THM Packaging Advantages:
- Easier approach to testing and prototyping as the THM components are typically easer to replace.
- Greater power tolerances as compared to SMT.
- Reliability and durability as a result of the very secure connection to the printed circuit board.
THM Packaging Disadvantages:
- Sourcing THM components is more difficult as compared to SMT components.
- Typically, manual placement of THM components is required, resulting in longer production times.
- THM components have a much larger footprint than SMT components.
- Less than optimal RF performance.
Surface Mount Packaging (SMT)
Surface mount packaging (SMT) is exactly that, the process of installing components directly on the surface of a printed circuit board. While this packaging production process is faster than THM, it raises the occurrence of defects as the components are positioned very closely together. Like THM components, SMT components are offered in ceramic, metal, glass and plastic packaging.
SMT Packaging Advantages:
- SMT components have a very small footprint.
- Faster production times as a result of automated placement capabilities.
- At volume, SMT component production costs are much lower than THM components.
- SMT components have excellent electromagnetic compatibility performance (EMC).
- Optimal RF performance.
SMT Packaging Disadvantages:
- While SMT components have a smaller footprint, they experience greater rates of defectiveness as the components are positioned so closely together.
- The majority of SMT components do not function effectively in high-power applications.
Have you considered RF component hermiticity?
It goes without saying that the operation of RF components in space requires heightened reliability and survivability. Unique environmental factors such as radiation, outgassing, shock and vibration present real challenges for RF components. To counter these threats THM and SMT components can be hermetically sealed. A hermetic seal is an air tight seal that is used to keep pollutants such as gases, liquids and solids from contaminating a package. Glasses, metals and ceramics are the common materials used to keep pollutants from entering RF packages. When it comes to hermiticity standards the MIL-STD-883 (Test Method 1014) is the universally accepted method used to determine effectiveness.
What packaging type should I select for my space bound RF components?
Launch vehicle and satellites RF components must meet the quality standards required to survive the intense environmental, electrical and mechanical challenges presented in LEO, MEO and GEO orbits. Even though SMT is the “modern” packaging approach and has some distinct advantages over THM components, THM won’t be going away anytime soon.
When choosing an RF component packaging approach for space applications, carefully consider the following decision factors:
- Production Time- If your project requires high volume production, consider SMT.
- Size- If component size is a major factor, consider SMT to achieve smaller footprints and tighter component densities.
- Capabilities- SMT requires a high level of design, manufacturing, expertise and technology. If this is a challenge, consider 3rd party support.
- Budget- If cost is a factor, consider THM to achieve lower production .
- Reliability- If your project requires the highest reliability possible, consider THM.
- Pin Count- If your project requires a high pin count, consider SMT.
- RF Performance- For optimal RF performance, consider SMT packaging.
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