TAS5630B Thermal information

Hello Dapkus,

Thanks for the reply.

We have used TAS5613 in our previous product. In the datasheet of TAS5613 the theta JC is 3.2 C/W.

TAS5630B output wattage is higher than TAS5613 so this question raised.

Regards,

Sreekanth

One more question i have, Does this theta JC depends on the size of the heat sink?

Don, this is about different but related subject. I will create a new topic if you think that is appropriate.

My question is related to item #3 in http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/t/144695.aspx on Nov 08, 2011: "The DKD package ratings are now mostly worse than the PHD package ratings, despite the DKD package having a larger thermal tab. That seems counter-intuitive." The TI reply on Nov 11 was "That's a mistake. Good catch, -we are working on a new set of thermal parameters. There is no doubt that the DKD package is thermally better than the PHD package." But TAS5630B.pdf (SLES217C revised September of 2012) still shows the DKD package having much worse thermal characteristics than the PHD package. Is this actually true? If so, why? The PHD thermal tab is more balanced and the PHD package is thinner, but the large difference between thermal characteristics still seems counter-intuituve. 

Another curiousity: TAS5630B.pdf still has a picture only of the PHD package -- no picture of a DKD package. It does have drawings but they can be misleading, as noted in http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/t/246372.aspx .

Hi, Sreekanth,

I might suggest you review this for an over-view of thermal resistance: http://en.wikipedia.org/wiki/Thermal_resistance

This one goes into more detail: http://www.aavid.com/sites/default/files/technical/papers/how-to-select-heatsink.pdf

-d2

Hi, Russell,

What Soren posted is still accurate. He is the father of these devices!!!

It's a long story of why this is still wrong in the d/s; I won't bore you with the details...

-d2

Hello Dapkus,

Thanks for the link. 

We have selected the heat sink required based on the calculations.

Why we doubted the values were because of very low Theta JC when compared to TAS5613 and note 2 under the thermal information table which says ''Thermal model data was performed using a 40 x 40 x 90mm heat-sink''.

Regards,

Sreekanth

Hi, Sreehanth,

You are welcome! Thermal performance is a little bit tricky...

RthetaJC is affected by the die size, and the area on the die generating the majority of the heat. These two devices have quite different die in them to accommodate the increase in output power.

-d2

Are the theta JC characteristics for the 5630B still wrong in the datasheet, because what I see is that the PKD has smaller resistance than the DKD?

Thanks