Wireless communication and advanced radar systems require circuitry that can operate at frequencies greater than 2 GHz and at high power levels. Analog gallium arsenide (GaAs) semiconductors are frequently used in these applications and present additional challenges for thermal engineers compared to silicon semiconductors. Whereas thermal characterization modeling and … [Read more...]
Thermal I/O
Don't do a spit-take with your coffee - there is no double-sided BGA. It would never see the light of day, simply because no one would ever buy it. Sure the density is unbeatable, but there is no practical method of soldering all the leads on such a package to a printed circuit board. No electrical hardware design engineer would accept such a ridiculous package. Then why do … [Read more...]
The Many Flavors of Ball Grid Array Packages
By now, it is a tired truism to say that the consumer electronics industry has consistently delivered on its promise to provide products that are smaller, faster, and more feature-rich at an ever cheaper price. The main driver for these trends has been the increasing integration of more functions on a single chip. In spite of its greater performance, the PC of today has far … [Read more...]
High Resolution, Real Time Micro-thermal Imaging — Steady State and Pulse Measurements on Microscopic Semiconductor Targets
Thermal imaging of microscopic targets has evolved over the past 20 years to the point where real time "true-temperature" mapping with 50 milliKelvin sensitivity and 2.75 �m spatial resolution is possible. Recently, the capability to study and evaluate high frequency transient pulses has been added. Infrared imaging methods provide unequaled ease and flexibility for … [Read more...]
Estimating Natural Convection Heat Transfer for Arrays of Vertical Parallel Flat Plates
A simple formula to estimate the natural convection heat transfer coefficient on a flat plate was presented in a preceding column [1]. If, instead of a single plate, we wish to consider a closely spaced array of vertically oriented parallel flat plates, a different formula is required. The geometry to be considered appears in Figure 1 and is typical of that for a vertically … [Read more...]
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