FR-4 PCB vs Ceramic PCB: Which One to Choose?
When it comes to choosing a printed circuit board (PCB), there are many factors to consider. Among them are the type of PCB material to use. FR-4 and ceramic are two of the most popular materials used in PCB fabrication. In this post, we'll compare FR-4 PCBs versus ceramic PCBs to help you decide which one is most appropriate for your specific application.
FR-4 PCBs
FR-4 (Fire Retardant 4) PCBs are the most commonly used PCBs for a variety of applications. This material is a type of composite consisting of a woven fiberglass cloth impregnated with an epoxy resin binder. FR-4 PCBs offer good electrical insulation, high temperature resistance, and good mechanical strength.
Properties of FR-4 PCBs
- Electrical insulation: 3×10¹⁰ Ω·m
- Thermal conductivity: 0.3 W/m·K
- Glass transition temperature (Tg): 135 °C
- Water absorption: 0.2%
- Dielectric constant: 4.5
Advantages of FR-4 PCBs
- Cost-effective
- Easy to manufacture
- Widely available
- Good mechanical strength
- High thermal resistance
- Good electrical insulation
- Compatible with high-frequency applications
- Good dimensional stability
Limitations of FR-4 PCBs
- Limited high-frequency performance
- Low dielectric constant
- Lower temperature resistance compared to ceramic PCBs
Ceramic PCBs
Ceramic PCBs are made of ceramic materials such as aluminum oxide (Al₂O₃) or aluminum nitride (AlN). Ceramic PCBs offer excellent thermal conductivity, high temperature resistance, and superior electrical insulation.
Properties of Ceramic PCBs
- Electrical insulation: 10¹⁴ Ω·m
- Thermal conductivity: 24 W/m·K (AlN), 25 W/m·K (Al₂O₃)
- Glass transition temperature (Tg): 50-100 °C
- Water absorption: 0%
- Dielectric constant: 9.8 (Al₂O₃), 8.5 (AlN)
Advantages of Ceramic PCBs
- High thermal conductivity
- High-temperature resistance
- Excellent electrical insulation
- Superior mechanical stability
- Higher dielectric constant
- Better high-frequency performance
Limitations of Ceramic PCBs
- Expensive
- Difficult to manufacture
- Not widely available
- Brittle
- Poor dimensional stability
Which One to Choose?
The choice between FR-4 and ceramic PCBs ultimately depends on the specific requirements of your application. If cost-effectiveness, easy of manufacturing, and high mechanical strength are critical factors, then FR-4 PCBs are a more practical choice. If the application demands high performance, high-temperature resistance, and excellent electrical insulation, then ceramic PCBs are the way to go despite their higher cost.
Conclusion
FR-4 and ceramic PCBs are two popular materials used in PCB fabrication, having different properties, advantages, and limitations. Ultimately, the choice of PCB material for a given application depends on the requirements of the specific application. This comparison should provide you with enough information to make a well-informed decision.
References
- "The Complete Guide to FR-4 - What It Is and Why It's Popular" by Altium
- "Understanding Ceramic PCBs: Materials, Applications, and Design" by Sierra Circuits
- "Ceramic Printed Circuit Boards – An Overview" by PCB Universe.