Introduction When faced with the task of calculating the temperature of an IC in a package, which has an external heat sink mounted to it, a thermal engineer usually obtains a values of three thermal resistances: ΘJC , the junction-to-case thermal resistance for the package, ΘCS , the case-to-sink thermal resistance representing the thermal interface material (TIM) between 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...]
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...]
Using an Equivalent Heat Transfer Coefficient to Model Fins on a Fin
Many readers of ElectronicsCooling are probably familiar with the use of fin efficiency formulas to estimate the thermal resistance of the commonly used parallel plate fin heat sink. Given the heat transfer coefficient, h, acting on a fin and the dimensions of the fin, the thermal resistance of an individual fin is given by: where Af and η are the surface area and … [Read more...]
Server Design Challenges for the High-heat-load Internet Data Center
Introduction Microprocessor and system thermal management are linked to facility cooling: power dissipation and cooling techniques employed at one end of the size scale have cascading impacts at the other extreme (Figure 1). For example, ineffective airflow distribution or insufficient underfloor static pressure in a data center can reduce the supply airflow rate from … [Read more...]
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