TPS62120: TPS62120 junction temperature calculation

Wei-Hao Chen (TW-FAE)

Part Number: TPS62120

Hi team,

My customer is using TPS62120-Q1 and want to verify what is the correct calculation to estimate correct junction temperature of the chip. The case temperature we measured is 107 deg on IC top-case.

Should we use ψJT or RθJC(top) described in the datasheet for junction temperature calculation?

Thanks.

Best Regards,

Wei-Hao

over 4 years ago

0 Spandana Kocherlakota over 4 years ago

TI__Intellectual 1595 points

Hi Wei,

ψJT is the true thermal metric to estimate junction temp from case temp measurement. The theta ja number is hinged on a standard PCB size of 3x3 and 2oz of copper thickness.

0 JohnTucker over 4 years ago in reply to Spandana Kocherlakota

TI__Guru**** 191445 points

Wei,

Yes you should use ψJT to calculate the junction temperature. The thermal parameters are based on the JEDEC standard coupon, which I believe is 4" x 4.5". It is NOT thermally optimized for dc/dc converter applications, so your design may possibly (or not) have better thermal performance.

0 Wei-Hao Chen (TW-FAE) over 4 years ago in reply to JohnTucker

TI__Expert 3260 points

Hi Spandana and John,

Thanks for your answer.

Best Regards,

Wei-Hao

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TPS62120: TPS62120 junction temperature calculation