Issue link: https://iconnect007.uberflip.com/i/340751
26 The PCB Magazine • July 2014 for future high-added-value PCB products and innovative solutions, forward integration will be important for PCB fabricators. In the experiment, standard PCBs where as- sembled with four Mosfet components powered with 1.5 W. The PCBAs were operated for some time and then the surface temperature was measured. Using thermography measurement methods, the temperature showed hot spots of >188°C at the components. Even the thermo- sensor still showed a temperature of 110°C. Life expectation of electronic devices depends on the operating temperature of the components and the co-efficient of thermal expansion in X-Y and Z direction. Operating an electronic device at a lower temperature will increase the life expectancy or the mean time between fail- ures (MTBF). Repeating this experiment with the same layout, the same type of components and same manufacturing technology was used to embed the components inside the PCBs. In this pro- cess, the components are completely surround- ed by epoxy resin and glass fibres used in copper clad laminate and prepregs. A dramatic temper- ature drop at the component was achieved. As shown in Figure 10, the thermal conductivity of the base material indicated no hot spots on the DEvICE EMBEDDING IN PCBS: EvOLUTION OR REvOLUTION? continues Figure 10: components embedded inside the PcB assembly have shown much lower temperatures based on better thermal conductivity of ccl compaired to air [2] . Figure 9: the thermal conductivity of different materials used in PcBs indicate that air is not the prefered media when thermal disipation is required. epoxy resin has a 0.35 W(m/K) thermal conductivity and glass has 1.05 W(m/K) [9] .