What Maximum Temperature Can the Printed Circuit Board Withstand
One of the core properties of printed circuit boards is temperature resistance. Material determines how much heat a board can manage. This article introduces the maximum temperature that PCB boards can withstand.
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Printed Circuit Boards are a vital component of electronic devices. They’re used in a variety of electrical instruments and devices. Temperature resistance is one of the most important properties. So what is the optimum temperature that the PCB board can withstand? Let’s look at the PCB temperature resistance.
1. PCB Temperature Resistance Performance
Temperature resistance of the Printed Circuit Board indicates that the board won’t show embrittlement or cracking in a high temperature environment.
What is Tg?
- Physical Significance: When the ambient temperature exceeds the Tg value, the mechanical properties of the circuit board will become unstable, making it prone to deformation, delamination, or degradation of electrical performance.
- Difference from Melting Point: It should be noted that the Tg value is not equivalent to the melting point of the material; instead, it represents the turning point of the material’s mechanical stability.
Safety Margin: The 20°C – 25°C Principle
- Design Standard: The Tg value of the material you select should be at least 20°C to 25°C higher than the maximum expected operating temperature of the device.
- Example Illustration: If your PCB uses standard FR-4 material with a Tg of 130°C, the actual operating temperature of the device should be strictly controlled below 110°C to guarantee safety.
The temperature resistance of the board, therefore, is very important. In normal circumstances, the temperature resistance of PCB processing can be affected by a number of factors, including material, manufacturing process, circuit design, and others.
The material is the most important factor that influences the temperature resistance of the PCB.
2. Common Materials and Their Temperature Resistance Limits
| Material Type | Glass Transition Temp (Tg) | Max Operating Temp | Key Features | Industry Examples |
| Standard FR-4 | ~130°C | 90°C – 110°C | Low cost, easy processing, high price-performance. | General consumer electronics |
| High-Tg FR-4 | 150°C – 170°C+ | 130°C – 150°C | High reliability, mechanical stress resistance. | ISOLA IS410, IS420, ARLON 85N, VT-901 |
| Polyimide (PI) | N/A (High Stability) | 380°C – 500°C+ | Chemical & EMI resistance, extreme durability. | Aerospace, Military, Precision instruments |
2.1 Product FR-4
FR-4, a glass-fiber reinforced epoxy product, is frequently used in PCB manufacturing.
The temperature resistance for FR-4 is usually around 130°C.In practical applications, it is mainly suitable for conventional environments where the continuous operating temperature ranges from 90°C to 110°C. Exceeding this level can cause the board to deform or fail. FR-4 materials have been extensively used by the high-end electrical industry for many years due to their low production costs, excellent price performance and easy processing. For high-temperature application, however, the resistance to temperature of FR-4 materials is not sufficient.
2.2 High-Temperature FR-4 Material
High-temperature FR-4, a glass-fiber-reinforced epoxie product, is specially designed for high temperature environments.
High-temperature FR-4 is a glass fiber reinforced epoxy product that has been specially designed for high temperature environments.
High-temperature FR-4 has a high production cost, but its reliability at high temperatures is much greater than that of FR-4. It is therefore widely used in the electrical industry.
2.3 Polyimide Product
Polyimide, a high-performance protective product, has exceptional properties such as high-temperature resistant, chemical degradation resistance, electromagnetic wave interference and others.
It is one the best high-temperature resistant materials available, with heats exceeding 380°C. Very few brands can endure temperatures above 500°C. Polyimide is used in aerospace, military, and temperature measurement instruments with high precision. Polyimide materials are expensive, but their durability at high temperatures makes them unbeatable.
The PCB temperature resistance can be as high as 500°C, or even higher, depending on what product is used on the board. Electrical tools and meters are generally made of FR-4 or high temperature FR-4 material, which is able to meet the needs of most applications.
In some applications, like aerospace, the army and other sectors, high-performance polyimide materials are required. When choosing PCB materials, it’s important to choose the right material and temperature resistance level for the application. This will ensure that the board is reliable and stable in high temperatures.
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