TPS7A4533 power dissipation and thermal

Ravi Chaudhari

I want to use TPS7A5433 in my design. Input voltage is12V and out put is 3.3V, 1.5A current. As per thermal calculation in TI Tjuncation temperature is going at 982.5 degree Celsius.

As per calculation

Power Dissipation (Pd) = (Vin-Vout) x I load
= (12-3.3)V x1.5A
= 13.5W

Temperature rise by LDO due to its own dissipation

Trise = ΘJA x Pd

= 50.5degC/W x 13.5W

= 681.75degree C

As per calculation I can use this LDO if load current is less than 0.2A, am I right?

Which calculation base part provide 1.5A load current?

Would you please answer my query and guide me?

Also answer I can go with this part in my design.

Regards,

Ravi

over 11 years ago

0 Ryan Eslinger over 11 years ago

TI__Guru 55940 points

Hi Ravi,

I am not aware of a TPS7A5433, did you mean TPS75433?

Very Respectfully,

Ryan

0 Ravi Chaudhari over 11 years ago in reply to Ryan Eslinger

Prodigy 80 points

Hi Ryan,

Typo error in part number.Part number is TPSA4533. You can get datasheet on mention link.

http://www.ti.com/lit/ds/slvs720d/slvs720d.pdf

Please reply asap.

Thanks & Regards,

Ravi Chaudhari

0 Benjamin Mak over 11 years ago in reply to Ravi Chaudhari

TI__Intellectual 2190 points

Ravi,

What is your max ambient temperature? The TPS7A4533 has a maximum junction temperature of 125C. If the junction temperature exceeds this temperature, the device will not be able to function.

In the case of your application, the junction temperature will far exceed the 125C maximum.

Thanks,

Ben

0 Ravi Chaudhari over 11 years ago in reply to Benjamin Mak

Prodigy 80 points

Hi Ben,

Thanks for reply. Maximum ambient temperature is 30C.As per calculation If I use 1A load temp. rise in KTT and DCQ is 243.6C and 439.2C.In this condition I can not use it.

Regards,

Ravi Chaudhari

0 Ravi Chaudhari over 11 years ago in reply to Ravi Chaudhari

Prodigy 80 points

Hi Ben,

As per datasheet o/p current is 1.5A but I can not use in my design case.Which parameter and which condition base datasheet mention it?

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TPS7A4533 power dissipation and thermal