Thermal characteristics of buried resistors

Finite-element modeling and experiments using an infrared camera were carried out to determine the temperature distribution and hence the power rating of buried resistors. The length-to-width ratio of the buried resistors considered ranged from 1 to 5 while their areas ranged from 0.3 to 20 mm/sup 2/. The power applied to the buried resistor was from about 10 to 500 mW. The results showed that the temperature of the buried resistor increases almost linearly with applied power. The effect of length-to-width ratios is relatively small. The temperature of the buried resistors drops significantly in the presence of copper layers; however, the effect of adding more than one layer of copper is relatively small. An equation for determining the power rating of the resistors based on their area is suggested.<
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