LM2596: Allowable Max Power Dissipation

Kei Kuwahara

Part Number: LM2596

Tool/software:

Hello team,

I would like to know the max power dissipation for this device (TO-220 package).

Max power dissipation without heat sink.
Max power dissipatioon with Thermalloy Heat Sink #7020 at " Figure 9-18. Junction Temperature Rise, TO-220 " of LM2596 datasheet

On the datasheet, the Abs Max value of Power Dissipation is "Internally Limited".
What does "Internally Limited" mean?

Best Regards,
Kei Kuwahara

+1 Frank De Stasi over 1 year ago

Hello

First, subtract 150C from your maximum ambient temperature.

Then divide that by the 50 (from the data sheet table).

That gives the maximum power.

You can translate the max power into max load current by using

the efficiency and the equation: Ploss=Pout*(1-n)/n

With a heatsink, you add 2 (from the data sheet table) to your heatsink

thetaJA and use that number for your calculation.

You can re-arrange these equations to give different parameters.

Also, see attached application note.

Thanks

+1 Frank De Stasi over 1 year ago in reply to Frank De Stasi

Hello

The phrase "Internally Limited" means that the device will shut off at junction temperatures above 150C.

Thanks

Power management forum