How can I calculate the junction temperature of an LDO?

Absolute maximum rated junction temperature specified

The maximum junction temperature of an LDO can be calculated from its power consumption and thermal resistance using Equations 1 and 2.

For example, suppose that VIN=1.5 V, VOUT=1 V, IOUT=200 mA, IB=20 μA, PD=0.6 W, and Ta=60°C. Then, the maximum junction temperature of the LDO can be calculated as follows.

Power consumption
From Equation 1, power consumption (P) is calculated as follows:
Absolute maximum rated junction temperature specified
From Equation 2, the maximum junction temperature is calculated as follows:
Circuit diagram

Allow a sufficient temperature margin for the thermal design of an LDO application.

Also see the following documents and web page for a description of junction temperature:

For other LDO regulators, visit the main web page of LDO regulators at:

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