With the development of integration technology and microelectronic packaging technology, the total power density of electronic components is increasing, while the physical dimensions of electronic components and electronic devices are gradually becoming smaller and miniaturized, and the generated heat is rapidly accumulated, leading to integration. The heat flux density around the device is also increasing, so the high temperature environment will definitely affect the performance of electronic components and equipment, which requires a more efficient thermal control scheme. Therefore, the heat dissipation problem of electronic components has evolved into a major focus of current electronic components and electronic device manufacturing.
In response to this situation, engineers have come up with some thermal management strategies: for example, by increasing the thermal conductivity of the PCB (high TC) to improve heat dissipation; focusing on allowing materials and devices to withstand higher operating temperatures (high Thermal Decomposition Temperature) Strategy; need to understand the operating environment and the thermal adaptation of the material to the degree of thermal cycling (low CTE). Another strategy is to use more efficient, lower power or lower loss materials to reduce heat generation.
There are three general heat dissipation methods: heat conduction, convection, and radiation heat transfer. Therefore, the commonly used thermal management methods are as follows: when designing the circuit board, deliberately increase the thickness of the heat-dissipating copper foil or use a large-area power supply, ground copper foil; use more heat-conducting holes; use metal heat dissipation, including heat sink, local Inlaid copper block. Or in the assembly, add a heat sink to the high-power device, the whole machine is added with a fan; either use thermal conductive adhesive, thermal grease or other thermal conductive material; or use heat pipe cooling, steam cavity radiator, high efficiency radiator.
At present, a new thermal solution has emerged on the market: it is advocated to use high Thermal Decomposition Temperature (TD) and high thermal conductivity (TC) plates for circuit board design. For example, Rayming currently represents ROGERS's 92ML series laminates. As a global leader in high-frequency circuit materials, Rogers' high thermal conductivity PCB material 92 ML series has several excellent features, the most notable of which is that the thermal conductivity of rogers 92ML is 4 to 8 times that of standard FR-4 ( epoxy). !
The characteristics of the high thermal conductivity PCB material rogers 92 ML are as follows:
- Thermal conductivity (Z-axis) is 2W/M.K (ASTM E1461)
- Glass transition temperature Tg: 160 °C
- Thermal Decomposition TemperatureTd: 400 ° C (5%)
- Z-axis thermal expansion coefficient (50-260 ° C): 1.8%
- UL maximum operating temperature: 150 ° C
- The same medium thickness withstand voltage is higher, the stability is good, suitable for high power and high pressure design
- Halogen free
Then, compared with the general thermal management plan, where is the Rayming rogers 92ML material solution winning?
In standard industrial test methods and models, it is assumed that the material is isotropic and only passes through the thermal conductivity of the plane; planar heat dissipation is usually used to reduce the hot spot temperature and increase the heat transfer throughout the region. The Rayming 92ML solution not only reduces the junction temperature of the device, but also increases the power output by about 15% or higher. Compared to the conventional FR-4, the 92ML can be further reduced by 30 ° C to 35 ° C (depending on the specific design). It can also reduce the hot spot peak temperature by increasing the Z-axis heat transfer and increasing the thermal diffusion of the X and Y axes. With a 1⁄4 brick DC-DC converter that does not exceed the recommended temperature of the device, it also has a higher power output, and an increase in heat transfer also increases power capacity. Moreover, the rogers 92ML solution has a very strict design for flatness and improves the flatness of the PCB. Its lower Z expansion factor also increases PTH reliability. The 92 ML series is available: prepreg, copper clad, metal substrate (SC92®); and the test sample has passed the Interconnect Stress Test (IST).
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