High TG, also known as high temperature, refers to high heat resistance in PCB raw material. High TG for copper clad laminate is greater than 170℃ while the standard Tg is between 130 – 140℃. So high tg pcbs mean printed circuit boards with Tg≥170℃, which is suitable for extreme-temperature processes that are commonplace in applications such as automotive, industrial or high-temperature electronics. Besides, as a result of development of SMT, CMT with high density pcb assembly technology, the PCB manufacturing with small hole size, fine lines and thin thickness are more and more inseparable from the support of high heat resistance.
FR-4 is a grade designation for flame-retardant fiberglass reinforced epoxy material. Thus, FR-4 PCB offers a much greater level of resistance to heat than a standard PCB. In the hot state, especially in the heat absorption with moisture, the high Tg PCB substrate will perform better than general FR4 in the aspects of mechanical strength, dimensional stability, adhesiveness, water absorption and thermal decomposition.
If you are working with high power density designs whose heat generation is likely to overwhelm your heat sinks or other heat management methods, a high-TG PCB is the best solution. A few application examples of these PCBs include:
Down hole oil drilling equipment
Medical diagnostic instruments