TS2937

500mA Ultra Low Dropout Voltage Regulator

4/10

Version: B07

Application Information (Continue)

Thermal Characteristics

A heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the

application. Under all possible operating conditions, the junction temperature must be within the range specified under

calculated.

IIN = IL / IG

= 400mW + 36mW

= 436mW

The next parameter which must be calculated is the maximum allowable temperature rise.

TR(max) is calculated by the using to formula:

TR(max) = TJ(max) – TA(max)

Where: TJ(max) is the maximum allowable junction temperature, which is 125

is the maximum ambient temperature which will be encountered in the application.

Using the calculated values for TR(max) and PD, the maximum allowable value for the junction to ambient thermal

resistance, θja, can now be found:

θja = TR(max) / PD

IMPORTANT: if the maximum allowable value for is found to be ≥6

TO-263 package, ≥150

since the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for θja falls

below these limits, a heatsink is required.