LM25145: thermal calculation of Tcase

Hardy Xue

Part Number: LM25145

Hi team,

I have questions for thermal calculation. How do we get a reliable Tcase(top) value of calculation by using RJA and RJC? Could I use below formula to calculate?

1. TJ = TA + (PD • RθJA), how to use TJ value to get Tcase(top)?

2. TJ = TC + (PD • RθJC), Could I use TJ value of formula 1 to get TC?

Best regards,

Hardy

over 4 years ago

0 Victor Yu over 4 years ago

TI__Expert 5321 points

Hi Hardy，

Generally speaking , Tcase is tested by Infrared imager.

I don't think you can use TA to calculate TC, that will be a wrong value.

BR,

Victor

0 Victor Yu over 4 years ago

TI__Expert 5321 points

Hi Hardy,

You can refer to this file. It detailed explain Thermal Resistance Parameters. If you have any question, please feel free to reach out. We can discuss on this topic by email or webex.

How to Properly Evaluate Junction Temperature with Thermal Metrics.pdf

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LM25145: thermal calculation of Tcase