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...]
CFD: One measly letter away from CAD
"The stuff you engineers design is too good," the guy from Marketing said, "I need shoddier! Can you make them less efficient and cheaper?" I was working for a small company that made electric power conditioning equipment. Our devices protected against spikes, sags and brownouts in the AC power for mission-critical equipment like air traffic control radar and the computer … [Read more...]
Component thermal characterization
For decades, the worldwide electronics industry has produced a stream of products that continue to amaze us with their capabilities, their compactness, and their low price. This track record is due, in part, to an intricate set of interrelationships between a large number of hardware and software vendors who balance cooperative and competitive market strategies. Key elements in … [Read more...]
Future trends in heat sink design
In today's electronics equipment, total system dissipated power levels are increasing with every new design. Increases in power levels combined with the market expectation of reduced package sizes lead to heat problems that, if uncontrolled, can significantly shorten the life of the electronics. Although this "increased power - decreased size" scenario has been prevalent for … [Read more...]
The thermal conductivity of air
In the Technical Data column of ElectronicsCooling Magazine, September 1998, the thermal conductivity of gases in general has been discussed. A few sentences were devoted to the temperature and pressure dependence of the most common gases. For example, it was stated that above 0.001 bar, the increase in thermal conductivity is of the order of magnitude of 1% per bar increase of … [Read more...]
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