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HEATSINK CALCULATION AND EXAMPLES
In many cases, GS-Rx and GSxTy-z modules don’t require any additional cooling methods because the dimensions and the shape of the metal boxes were studied to offer the minimum possible thermal resistance case to ambient for a given module. It should be remembered, that GS-R and GS-T modules are power devices i.e. products that deliver power and dissipate power and, depending on ambient temperature, an additional heat-sink or forced ventilation or both may be required to keep the unit within safe temperature range. We would like here to eliminate a wrong parameter that has been plaguing the technical literature of power devices for 30 years: the operating ambient temperature specified among Absolute Maximum Rating. The concept of operating ambient temperature is totally meaningless when we deal with power components, because the operating ambient temperature depends on how a power device is used. What can be unambiguously defined is the maximum junction temperature of a power semiconductor device or the case temperature of a module. To prove this, let’s consider the following example: