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...]
General aspects on fan selection and layout
Introduction and Description of Fan Types Small ventilators are generally called fans. Depending on the geometrical design of the impeller, various constructional types are distinguished to indicate the main direction of the airflow. Here are the descriptions of the most important types of fans: Axial Fans Axial fans are characterized by their typical impeller form, which … [Read more...]
Parameters affecting package thermal performance a low end system level example
Thermal management of electronic equipment is a dynamic process. For example, the anticipated power trends for CMOS technology can be found in the roadmaps of [1 and 2]. They closely follow the rapidly rising power trends seen in the 1980s for the bi-polar circuits [3] but with a time shift by a decade. It is a fortunate circumstance that a tremendous amount of heat transfer … [Read more...]
The submerged double jet impingement (SDJI) method for thermal testing of packages
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...]
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