1998

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Thermal testing and control by means of built-in temperature sensors

September 1st, 1998

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…read more

The thermal conductivity of gases

September 1st, 1998

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…read more

Recent Japanese thermal solutions for portable computers

September 1st, 1998

Introduction Mobile computing is poised to shape the way we live our lives, allowing people to generate, retrieve, and process data anywhere and at any time. The infrastructure for mobile computing is rapidly developing, as…read more

Heat transfer measurements in electronics cooling applications

September 1st, 1998

Introduction Increased performance in electronic systems along with higher packaging densities have made temperature a critical parameter. Measurements of temperature, velocity and heat transfer in electronic systems are challenging due to complex materials, configurations, and…read more

Disk drive reliability and thermal management

September 1st, 1998

Disk drive reliability and thermal management Hard disk drives are electromechanical systems which store information. They are the most complex electronic sub-assembly within a computer. If a microprocessor can qualify as the “heart” of a…read more

Cooling Electronics at High Altitudes Made Easy

September 1st, 1998

Introduction High altitude air cooling has always been somewhat of a mystery to the uninformed. The first reaction to the situation is that there is just not enough air at altitudes greater than six kilometers…read more

Convection and radiation heat loss from a printed circuit board

September 1st, 1998

In last issue’s column, a method for calculating the thermal conductivity of a printed circuit board (PCB) was described. Now, we look at a more complicated heat transfer process, namely the loss of heat from…read more

Thermal management of handheld telecommunication products

May 1st, 1998

Introduction Recent advances in mobile communications have enabled large scale development of handheld telecommunication products. Such products include cellular phones, pagers, two-way radios, personal digital assistants (PDAs), and other wireless and wireline equipment. The technological…read more

Thermal interface under a plastic quad flat pack

May 1st, 1998

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…read more

The thermal conductivity of silicon

May 1st, 1998

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.…read more

Pressure drop coefficients for thin perforated plates

May 1st, 1998

Almost everyone working on pressure drop coefficients of perforated plates encounters the work of I.E. Idelchick {1}. A plethora of graphs or equations – some of which are impossible to evaluate quickly – must then…read more

Interaction of the system and module-level thermal phenomena- a flip-chip/BGA example

May 1st, 1998

Fig. 1: Levels in a computer environment. Introduction Increasing demands for higher performance in microprocessors have a direct effect on chip power and heat generation. Increased function and miniaturization of the packages result in thermal…read more

Forced convection cooling inside an electronics enclosure

May 1st, 1998

Introduction One of the more complex thermal problems in electronics is the modeling of complete systems, such as an enclosure containing electronic components. A typical example would be a power supply, including heat sinks and…read more

Conduction heat transfer in a printed circuit board

May 1st, 1998

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…read more