SLVS208J May 1999 – August 2015 TPS767
PRODUCTION DATA.
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Specified regulator operation is assured to a junction temperature of 125°C; the maximum junction temperature should be restricted to 125°C under normal operating conditions. This restriction limits the power dissipation the regulator can handle in any given application. To ensure the junction temperature is within acceptable limits, calculate the maximum allowable dissipation, PD(max), and the actual dissipation, PD, which must be less than or equal to PD(max).
The maximum-power-dissipation limit is determined using the following equation:
Where:
TJmax is the maximum allowable junction temperature.
RθJA is the thermal resistance junction-to-ambient for the package, i.e., 172°C/W for the 8-terminal SOIC and
RθJA 32.6°C/W for the 20-terminal PWP with no airflow.
TA is the ambient temperature.
The regulator dissipation is calculated using:
Power dissipation resulting from quiescent current is negligible. Excessive power dissipation will trigger the thermal protection circuit.