Over the past decades, the functionality of electronic parts has improved considerably. Increasing power requirements of semiconductor chips make it difficult to keep the temperature below the imposed limits. Thermal management of the chip is one of the main functions of the package. To fully characterize the package thermally, numerical simulations and experimental tests are … [Read more...]
The thermal conductivity of unfilled plastics
This time, the focus is on the thermal conductivity of unfilled plastics. There are hundreds of them, so only a small selection can be presented. From a thermal point of view, plastics are a notoriously difficult family. Different sources show large variations in the thermal conductivity, and handbooks provide a range of values for many materials instead of a single value. The … [Read more...]
Visualization of air flows in electronics systems
The three-dimensional shape and irregular nature of electronic component topologies on air-cooled Printed Circuit Boards (PCBs) give rise to complex air flow patterns that have been well documented [1]. Even laminar flows over relatively simple shapes, such as cubical metal blocks simulating electronic components, often exhibit multi-dimensional flow phenomena that include … [Read more...]
An alternative approach to junction-to-case thermal resistance measurements
As more and more integrated circuits dissipate power at levels once reserved for power discrete devices, junction-to-case thermal resistance (JC or RJC) remains as important as ever. The difficulties in making JC measurements often leads to values that do not accurately indicate true junction temperature (TJ). The measurement difficulties are usually two-fold. First is … [Read more...]
Characterizing a package on a populated printed circuit board
This column has emphasized methods of analyzing packages in the JEDEC-standard test environment. A thermal metric that lends itself to analyses of system applications is the junction-to-board thermal characterization parameter, JB. If one knows the board temperature (TB), then the junction temperature (TJ) can be determined by a simple application of the following formula: TJ … [Read more...]
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