As you know, when the temperature rises to a certain area, the base material (polymer or glass) is changing from a glassy, solid, and rigid state to a rubbery state, so the temperature at this time is called the glass transition temperature (Tg) . In other words, Tg is the mechanical property that specifies the glass transition temperature, that is, the highest temperature at which the glass maintains rigidity. In other words, ordinary PCB substrates will not only soften, deform, melt and other phenomena at high temperatures, but also the mechanical and electrical properties will drop sharply, which will affect the service life of the product.

High TG PCB

Needless to say, the normal PCB FR4-Tg is 130-140 degrees, the medium Tg is greater than 150-160 degrees, and the high Tg is greater than 170 degrees. Compared with standard FR4, high FR4-Tg has better mechanical and chemical resistance to heat and humidity. The higher the Tg value, the better the heat resistance of the material. Therefore, especially in the lead-free process, the Tg is getting higher and higher.

High Tg PCB performance

 With the rapid development of the electronics industry, high Tg materials are widely used in computers, communication equipment, precision instruments, and instrumentation. In order to achieve high-function, high-multilayer development, PCB substrate materials require higher heat resistance as a prerequisite. Moreover, due to the emergence and development of high-density mounting technologies represented by SMT and CMT, in the case of thinning, small aperture, and fine wiring, the high heat resistance of the substrate and the substrate are becoming more and more inseparable. Therefore, the difference between general FR-4 and high FR4-Tg is that mechanical strength, adhesion, water absorption, dimensional stability, and thermal decomposition under thermal conditions (especially after water absorption) are under different conditions (such as thermal expansion). ) The difference is obvious, high Tg PCB is better than ordinary PCB substrate materials. Therefore, in recent years, there has been a great demand for high Tg PCBs, but the prices are higher than ordinary PCBs.

 More importantly, high Tg materials are also popular in the LED lighting industry, because the cap dissipation rate of LED is higher than that of ordinary electronic components, but the same structure of FR-4 board is much cheaper than metal core PCB such as aluminum core PCB.

Advantages of high Tg PCB

 Higher stability: If you increase the Tg of the PCB substrate, it will automatically improve the heat resistance, chemical resistance, humidity resistance and the stability of the device.

 Withstand high power density design: If the device has a high power density and quite high heat, then a high Tg PCB will be a good solution for thermal management.

When reducing the heat generation of ordinary boards, larger printed circuit boards can be used to change the design and power requirements of the device, and high Tg PCBs can also be used.

Ideal for multi-layer and HDI PCBs: Since multi-layer and HDI PCBs are more compact and circuit dense, they will result in a high level of heat dissipation. Therefore, high Tg PCBs are usually used in multilayer and HDI PCBs to ensure the reliability of PCB manufacturing.

 When do you need a high Tg PCB?

If the thermal load that your printed circuit board cannot withstand is not less than Tg 25 degrees Celsius, your application will require a high Tg PCB. In addition, if your product operates in a temperature range of 130 degrees Celsius or higher, it can also ensure the safety of using high Tg PCBs. Needless to say, the main reason for high Tg PCB is the switch to RoHS PCB. Therefore, more and more PCB industries are turning to high Tg materials because lead-free solders to flow require higher temperatures.

Application field

If the power density in the electronic product is higher and the heat will interfere with the heat sink or other parts of the product, then a high Tg PCB is the best solution. In addition, with the popularity of high Tg PCBs in recent years, you will find that Tg PCBs are used in the electronics industry that can operate at higher temperatures. Therefore, we meet the needs of customers in different industries by providing high heat resistance and high Tg PCBs. These PCBs can meet customer specifications in a short delivery time. Therefore, they are some application examples as follows:

Gateway, RFID, inverter, antenna board, wireless booster, contract manufacturing service, low-cost PLC, embedded system development, embedded computer system, AC power supply.

We can manufacture specifications, please check the following:

Number of layers: 1-14 layers

PCB size: minimum 10 * 15mm, maximum 500 * 600mm

Finished board thickness: 0.2-3.5mm

Copper weight: 1/3oz-4oz

Surface treatment: lead-containing HASL / lead-free HASL / immersion gold / immersion silver / immersion tin / OSP-organic solderability preservative-RoHS

Solder mask: green/red/yellow/blue/white/black/purple/matt black/matt green

Silk screen: white/black

Minimum line width/spacing: 3 / 3mil

Minimum aperture: 0.1mm

Quality level: Standard IPC II