The value of thermal conductivity for most gases and vapors range between 0.01 and 0.03 W/mK at room temperature. Notable exceptions are Helium (0.15) and Hydrogen (0.18). The most common theoretical explanation of heat conduction in gases is provided by the kinetic gas theory, which treats the collisions between the atoms or molecules as the prime mode of transfer of energy. … [Read more...]
Thermal testing and control by means of built-in temperature sensors
Introduction This paper will discuss a new approach to the measurement of the thermal properties of PCBs and the packages mounted to them. It is intended to replace traditional solutions, such as using thermocouples and data acquisition equipment. The basic idea of this approach is that the IC chips themselves will be used to measure and acquire temperature data. It will be … [Read more...]
Conduction heat transfer in a printed circuit board
In this issue, we examine heat flow in a printed circuit board (PCB), which typically is a layered composite consisting of copper foil and a glass-reinforced polymer (FR-4). A cross-sectional view of such a laminated structure is illustrated in Figure 1. The Figure indicates the numbering system that will be used for indicating the different layers, numbered 1 through to … [Read more...]
The thermal conductivity of silicon
The most important material within the semiconductor industry is Silicon. When dealing with electro-thermal device modelling, or the interpretation of fast transient techniques for the measurement of thermal impedance, thermal conductivity of Silicon is required. For steady state thermal analyses at the board and system level, however, accurate values are not required, because … [Read more...]
Thermal interface under a plastic quad flat pack
Introduction Plastic components are designed so that the heat is dissipated by forced or natural convection. The use of plastic packages under conditions where neither cooling method is available introduces new challenges. High heat-dissipation plastic packages require a large-area solid heat sink in order to transfer the heat into the copper thermal lands on the printed … [Read more...]
