Dauerdurchlassstrom

Dauerdurchlassstrom is the maximum average current that a semiconductor device can conduct continuously under specified operating conditions without exceeding its maximum junction temperature. It is primarily a thermal specification: the allowable current is limited by heat generation from I^2R losses and therefore depends on ambient temperature, cooling, mounting, and the device’s thermal resistance.

Manufacturers specify Dauerdurchlassstrom as I_F(DC) for diodes or I_C(DC) for transistors, often as a function of ambient temperature (Ta) or case temperature (Tc). Datasheets may provide values at particular reference temperatures and sometimes derating curves that show how the current limit decreases as temperature increases or with reduced cooling.

Dauerdurchlassstrom is distinct from pulsed or peak currents, which can exceed the continuous rating when the device has time to cool between pulses. In design, thermal management is essential: heatsinks, airflow, mounting method, PCB copper area, and overall thermal resistance must be considered. Exceeding the Dauerdurchlassstrom can lead to overheating, performance loss, or failure.

Device ratings vary widely between components; power diodes, thyristors, and transistors each have their own continuous-current specifications. The rating must be used together with voltage ratings and thermal limits to define a safe operating area and to ensure reliable operation under expected operating conditions.