Tg stands for Glass Transition Temperature. As printed circuit boards (PCBs) are classified as V-0 (UL 94-V0) for flammability, if the temperature exceeds the designated Tg value, the board will transition from a glassy state to a rubbery state, thereby affecting the PCB's functionality.

If your product's operating temperature is higher than normal (130-140°C), you need to use high Tg material, which is >170°C. Common high Tg values for PCBs are 170°C, 175°C, and 180°C. Typically, the PCB Tg value should be at least 10-20°C higher than the product's working temperature. For example, if you use a 130 Tg board, the working temperature should be lower than 110°C; for a 170 Tg board, the maximum working temperature should be lower than 150°C.

To understand the differences between Tg 130 and Tg 170, please continue reading. Additionally, we have provided specifications for Tg 150 and Tg 170 to help customers better understand high Tg materials. For more information, read the comparisons: Tg 150 vs. Tg 170.

Here are some popular high Tg board materials available in the market:

• S1170 & S1000-2: SYL (Shengyi Technology)
• FR406, FR408, IS410 & DS370HR: Isola
• MCL-E-679: Hitachi
• N4000-6 & N4000-11: Nelco

There are many different high Tg materials not listed here. Different countries and companies may prefer different materials. Please refer to the datasheets for each material to choose the most suitable one for your needs. If not specified, we typically use S1170 from SYL.

170 Tg raw materials are also popular in the LED industry because the heat dissipation of LEDs is higher than that of normal electronic components. The same structure of FR4 boards is much cheaper than MCPCBs or Ceramic boards. The normal Tg value of MCPCBs is the same as standard FR4 PCBs, at 130-140°C. Customers can also request high Tg (170-180°C) for MCPCBs, but the thermal conductivity will only be (0.3-0.4 W/m.K).

If the PCB's working temperature is higher than 170/180°C, such as 200°C, 280°C, or even higher, it is advisable to use a Ceramic board, which can withstand temperatures ranging from -55°C to 880°C.