Material Selection for High-Reliability Aerospace PCBs

Vandana CC

Engineering Project Coordinator
Sierra Circuits

When designing aerospace PCBs, material selection is not just important; it is mission-critical. Unlike consumer electronics, where failures may be acceptable, avionic systems demand near-zero failure rates. If your PCB operates across extreme temperatures (−55°C to +125°C), with constant vibration, using inappropriate materials might lead to delamination or barrel cracking.

In this webinar, you will learn about thermal, electrical, and mechanical laminate properties and practical strategies for selecting aerospace PCB materials.

How to choose the right substrate for an avionic circuit board

Start by reviewing the material datasheets. Build a checklist that includes your design essentials, like operating temperature, frequency range, and mechanical stress levels. Then, pick suitable materials that align with these requirements.

For aerospace applications, select laminates with a glass transition temperature (T_g) above 170°C and a decomposition temperature (T_d) above 300°C. To maintain structural integrity, ensure your maximum operating temperature remains at least 20-30°C below the T_g.

CTE matching is another critical factor, especially under repeated thermal cycles. Select materials with a CTE that closely matches the copper CTE (~17 ppm/°C) to minimize stress in plated through holes.

Loss tangent and dielectric constant are two key parameters for aerospace PCB material selection. Opt for low D_k (<4) and low D_f (<0.005) substrates to reduce signal loss. Additionally, ensure the dielectric constant remains stable across frequency and temperature, as variations might result in impedance mismatches and signal degradation.

Moisture absorption and conductive anodic filament (CAF) resistance are often overlooked but can be vital in aerospace environments. CAF is an electrochemical mechanism that might lead to internal short circuits. To mitigate this risk, pick materials with moisture absorption below 0.10% and consider conformal coatings for added protection.

In this session, you will understand the key laminate properties and how to apply them in real-world avionic designs.

What you’ll learn:

• Why PCB material selection is mission-critical in aerospace devices
• Key laminate properties that impact reliability
• Preferred aerospace materials: polyimide, PTFE, and ceramic
• Standards that define aerospace design

About Vandana CC

Engineering Project Coordinator at Sierra Circuits

With a strong foundation in physics, Vandana CC brings a deep technical understanding to her work in PCB design and electronics manufacturing. She holds a Master’s in Physics and has experience teaching before transitioning into research at the Indian Institute of Science.

At Sierra Circuits, Vandana has played a key role in R&D projects, contributing to the development of engineering tools and calculators, technical content creation, and customer demos. Currently, she focuses on project coordination, ensuring seamless collaboration both within the team and with external partners. Her expertise bridges the gap between technical innovation and practical application, making her an integral part of Sierra Circuits’ engineering efforts.