Today's electronics are becoming smaller and faster, resulting in increased power densities and greater risk of thermal problems. Thermal dissipation requirements thus need to be satisfied by the use of several cooling mechanisms. The cooling systems may include conduction, convection and radiation cooling. Conduction can be the most efficient mode of heat transfer and about … [Read more...]
Natural convection modeling of heat sinks using web-based tools
Heat transfer in electronic packages is a complex problem involving a network of resistive paths for the various laminated structures, bonding adhesives, lead frames, and attachment mechanisms, such as ball grid arrays. However, despite the multitude of materials and interfaces within an electronic package, the largest thermal resistance, and consequently the controlling … [Read more...]
The increasing importance of thermal test dies
Thermal test dies are among the major tools used in package thermal design qualification. They are usually simple chips, containing heaters and temperature sensors. The sensors measure the temperature on the chip surface as a result of the steady state powering or the time dependence of the temperature increase or decrease in case of transient qualification. From these data, … [Read more...]
The thermal conductivity of fluids
About 10-15 years ago, fluids, either directly (mainly Fluorocarbons), or indirectly (cold plates flushed with water) cooled the majority of mainframe computers. Nowadays, the expected increase in heat flux density causes a renewed interest in either passive or active liquid cooling, because the limits of air cooling come within reach. Other practical applications in which … [Read more...]
Determining the junction temperature in a semiconductor package, part IV – localized heat generation on the die
In the standard thermal test environment, thermal test chips are designed to dissipate the applied power uniformly over most of the die surface. However, in many situations of practical interest, the power is dissipated over a localized area of the die. This column provides calculation methods to deal with the latter situation. Figure 1 illustrates the situation of interest … [Read more...]
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