Introduction Over the past few years many people in the electronics industry have become concerned with the increases in heat density at both the chip and module level of packaging. This trend is not new and has been with us since the days of bipolar chips. As can be seen in Figure 1, the heat flux associated with bipolar circuit technologies steadily increased from the … [Read more...]
Latest Developments In Thermoelectrically Enhanced Heat Sinks
Nomenclature Q Heat load (W) COP Coefficient of Performance I Electrical current (Amps) T Temperature (°C) R Electrical resistance (Ohms) Z TE Figure of Merit (1/K) where Z = α2 / (ρ λ) Greek Letters Δ Change in value θ Thermal resistance (°C/W) ρ Electrical resistivity (Ohm-cm) α Seebeck coefficient (V/K) λ Thermal conductivity … [Read more...]
Liquid Cooling is Back
Introduction IBM announced its return to water cooling on April 19, 2005 with the introduction of a water cooled heat exchanger mounted to the back cover of a 19 inch rack. This is the first of the major datacom equipment manufacturers to employ water cooling for a rack of CMOS processors, using a cooling distribution unit supplying the water and rejecting the heat load to … [Read more...]
Metals For Thin Wires – Criteria Of Choice
When a designer has to deal with thin current-carrying wires, a number of thermal issues pop up: Joule heating, heat losses and temperature measurement. For standard lead wires, one usually wants minimal Joule heating and minimum thermal resistance (in order to maximize the heat losses). Minimization of heat losses may be important for a research environment. Maximum Joule … [Read more...]
Vibration Analysis For Electronic Equipment
This topic is rather esoteric and usually an afterthought in commercial and industrial applications. In military and defense electronics, it is one of the major drivers for design and product architecture early on in the design cycle with specific targets/budgets. As with junction temperature requirements in a thermal design, there are structural dynamic issues that need to be … [Read more...]
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