TPS82084: TPS82084 operating junction temperature and thermal shutdown

RajK

Intellectual 740 points

Part Number: TPS82084

Hello,

Our application is as follows -

Input - 5V

Output - 1.8V

Max load current - 1.2A

Based on the datasheet, RθJA Junction-to-ambient thermal resistance is 64.6 degree C/W.

Based on the datasheet, thermal shutdown is at 150 degree C.

Power dissipation at full load P = (Vin - Vout) * Iout = (5 - 1.8) * 1.2 = 3.84 W,

and the junction temperature would be about

RθJA * P = 64.6 * 3.84 = 248.064 degree C.

Based on the above calculation, it seems the part TPS82084 would go into thermal shutdown for our application. Is this understanding correct ? If yes, could you please suggest an alternate part for our application requirement. Thank you

over 4 years ago

+1 Stefano Panaro over 4 years ago

TI__Expert 7685 points

Hi User,

Thanks for your question.

The device is a Switching regulator, thus you cannot evaluate the power dissipation with: P = (Vin - Vout) * Iout (this formula is valid for LDOs).

In this devices, the power dissipation is mainly due to conduction and switching losses.

Please refer to Techniques for Thermal Analysis of Switching Pwr Supp Designs (Rev. A) (ti.com) for power dissipation computation and Semiconductor and IC Package Thermal Metrics (Rev. C) (ti.com) for info on Package Thermal Metrics.

However, the device is a 2A device, thus it should bear your 1.2A output current without particular problems in standard operation.

Thanks,

Stefano

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TPS82084: TPS82084 operating junction temperature and thermal shutdown