Introduction In the 1990's, with the advent of surface mounting of semiconductor packages, multilayer printed circuit boards and multilayer substrates for Ball Grid Array packages were introduced. In order to create electrical interconnections between the different metal layers, vias are fabricated [1]. In most cases vias are hollow cylinders of copper, created by plating a … [Read more...]
Trends in Cooling of Electronics: The Use of Thermal Roadmaps
Introduction Miniaturization, integration of functionality, and the increase of clock speed are recognized business drivers in the electronics industry today. Consequences are the fast increase in power dissipation leading to higher heat fluxes, higher temperatures and larger temperature gradients. Handling these effects makes it more difficult to stay cost competitive, because … [Read more...]
Critical Cooling Issues in High Power Radio Frequency Transmitter Amplifiers
Introduction While emerging methodologies correctly insist that thermal engineers should be involved right from the early conceptual stages of electronics product design [1], many situations still require thermal analysis well after the introduction of the product to its intended application. Military transmitters installed in the 1980's and 1990's and still in operation today … [Read more...]
Modeling Heat Conduction in Printed Circuit Boards Using Finite Element Analysis
Introduction Heat transfer in and around a printed circuit board (PCB) is generally very complex. Some of the heat generated in components is conducted away through the multiple conducting (trace) layers, vias, and dielectric layers of the board; and some is dissipated by convection and radiation from the exposed surfaces. There has long been a focus on characterizing the … [Read more...]
Simple Formulas for Estimating Thermal Spreading Resistance
A problem commonly encountered in the thermal analysis of electronic packages is that of thermal spreading resistance. Thermal spreading resistance occurs as heat flows by conduction between a source and a sink with different cross-sectional areas. Examples of two situations involving spreading heat flow are shown in Figure 1. One example is that of a chip mounted on the bottom … [Read more...]
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