TPS3803-Q1: Power Rating

Mayur M Bharadwaj

Part Number: TPS3803-Q1

Hello,

As per the datasheet of TPS3803-Q1, the power dissipation rating is 321mW for Ta< 25 degrees C. Can you please let me know how this can be calculated theoretically?

Because, RθJA Junction-to-ambient thermal resistance is 246.6 °C/W. Operating temperature is 125C and ambient is 25C.

So, power rating = (Operating Temp - Ambient/ RθJA ) i.e. ((125-25)/246.6) gives 405.5mW and this is differing from what is there in datasheet.

So kindly let me know the procedure on how to derive the power rating if the above procedure is wrong.

over 2 years ago

0 Masoud Beheshti61 over 2 years ago

TI__Genius 15941 points

Hello,

321mW is the maximum power dissipation this package can handle at Ta<25C. This device cannot handle 405.5mW. That means you need to change your operating conditions or you thermal design accordingly. Hope that helps.

0 Mayur M Bharadwaj over 2 years ago in reply to Masoud Beheshti61

Intellectual 380 points

Hello,

Yes, but can you please explain how this 321mW power is derived theoretically?

0 Masoud Beheshti61 over 2 years ago in reply to Mayur M Bharadwaj

TI__Genius 15941 points

Hello,

321mW is calculated based on thermal modeling of the device and its package. Hope this helps.

0 Mayur M Bharadwaj over 2 years ago in reply to Masoud Beheshti61

Intellectual 380 points

Hello,

The power dissipation will be calculated using the below formula if I am correct.

For this IC, as per the datasheet,

Tjmax = 125

RθJA = 246.6 C/W

Hence Pd = ((125-25)/246.6) = 405.5mW

Theoretically it is coming as 405.5mW, but I wanted to know on what basis is it given as 321mW in the datasheet.

0 Masoud Beheshti61 over 2 years ago in reply to Mayur M Bharadwaj

TI__Genius 15941 points

Hello Mayur,

You are correct. "Theoretically" you should be able to dissipate 405.5mW in this package. However this package is only capable of dissipating 321mW. Which means you need to adjust your thermal and electrical design not to exceed this limit.

0 Mayur M Bharadwaj over 2 years ago in reply to Masoud Beheshti61

Intellectual 380 points

Hello,

Thanks for the clarification.

I wanted to know what will be the practical power dissipation capability of TPS3703A4120DSERQ1, since it is not given in the datasheet.

0 Masoud Beheshti61 over 2 years ago in reply to Mayur M Bharadwaj

TI__Genius 15941 points

Hello,

TPS3703A4120DSERQ1: sorry I don't have any data beyond the datasheet. But this is a voltage supervisor. There should really be no power dissipation with device as it does not handle power.

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TPS3803-Q1: Power Rating