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BQ21040: Heat dissipation_Thermal pad/cu area calculation

Part Number: BQ21040

Hi,

Does this part has a thermal PAD? In Datasheet it is not shown in Footprint as well as in schematic symbol, please clarify.

I want to calculate the Cu area for dissipating the power of 0.84W from this IC.

As per datasheet RθJA Junction-to-ambient thermal resistance is 130.8 c/w and Tj max is 150C

Temperature rise= θJA* Pd

                           =130.8 c/w*0.84w

                           =109.872 C

Assume my ambient temperature is 40C

Then T total= Tamb+Trise

=149.87

Head room left over Junction temperature is 150C-149.87C = 0.13C (Tjmax - Ttotal).

Datasheet mentions max current for charging is 1.25A. Please let me know what is the condition required to handle 1.25A ( if thermal PAD needs to be provided what is its area)

Thanks

Navaneeth