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...]
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...]
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...]
Thermal characterization of power ICs using virtual junction temperature
Thermal experts generally view thermal resistance as a measurable property of a semiconductor device. A system designer, who designs an appliance, is usually not a thermal expert. The system designer just needs a way to determine the size of the external heat sink. At high heat sink temperatures, less power dissipation is allowed in the device. The ratio at which case … [Read more...]
The treacherous streams
During the development of a telecommunications product, an unpredictable phenomenon of air streams within the maze of cards and module was encountered. It could only be compared to suddenly confronting powerful inner streams in a calm ocean. Unlike the ocean, however, these streams appeared in a man-made machine. It seemed as if someone had rewritten the laws of physics. It was … [Read more...]
- « Previous Page
- 1
- …
- 151
- 152
- 153
- 154
- 155
- …
- 176
- Next Page »