LM22672: Rjc & Rjb

Hello,

I do not see a description of the Rjc in the datasheet. Can you point me towards this number? Generally, you are correct that a thermal pad under the IC will allow increased thermal dissipation.

In general the thermal characteristics are characterized by the JEDEC standards. www.ti.com/.../spra953c.pdf

Second, this applications note is a good resource for thermally optimized design: www.ti.com/.../snva419c.pdf

Best Regards,
Katelyn

Hi Katelyn,

You are correct that the junction-case value is not on this data sheet.

Last time when i had asked about the Rjc and Rjb values i was informed to use this part as it is similar to LM22672:

http://www.ti.com/product/TPS54560B-Q1

The Rjb and Rjc values are provided in this part. I was wondering if i should be using the Rjc-Bottom values as Rjb in my thermal simulation due to the thermal pad in the bottom.

Thank you.

Regards,

Nikhil

Hi Nikhil,

Thank you for sharing the additional information. You can use both the Rjcb and Rjct for your thermal simulation.

However, the simulation results to test results will vary depending on the board layout. The Rjcb and Rjct are based on the JEDEC standard board.

Please let me know if you have any additional questions or if anything remains unclear.

Best Regards,
Katelyn