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MK.12
MK.12
Associate
August 8, 2022
Solved

Thermal resistance Rja and Rca of ST25R3916-AQWT

Hello,

I would like to receive information on the thermal characteristics of ST25R3916-AQWT.

Rja and Rca.

Let me know your input!

Cheers

Madhu

This topic has been closed for replies.
Travis Palmer
Travis PalmerBest answer
ST Employee
August 11, 2022

Hello Madhu,

Rtheta_jc is specific to the device (more in detail it is specific to the used package).

This is why we can very precisely can name this number.

Rthetha_ja is specific to the device / package, PCB (size, amount of copper, number of layers, ...) and housing / airflow. This means, this number (Rthetha_ja) is specific to the application itself and we cannot do a general statement here.

This is why we did this application note, showing how to setup the thermal model and measure / calculate the thermal resistance of each node (e.g. ja an ca on bottom and top).

BR Travis

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3 replies

Ulysses HERNIOSUS
Ulysses HERNIOSUS
ST Technical Moderator
August 9, 2022

Hi Madhu,

did you find and check AN5584: ST25R39xx NFC reader thermal design?

Best Regards, Ulysses

MK.12
MK.12Author
Associate
August 9, 2022

Hello Ulysses,

I did check the document. I was able to find Rtheta_jc as 16.95C. I dont think Rthetha_ja is not listed if I am right. So is it possible to get the correct value for Rthetha_ja?

Cheers

Madhu

Travis Palmer
Travis PalmerBest answer
ST Employee
August 11, 2022

Hello Madhu,

Rtheta_jc is specific to the device (more in detail it is specific to the used package).

This is why we can very precisely can name this number.

Rthetha_ja is specific to the device / package, PCB (size, amount of copper, number of layers, ...) and housing / airflow. This means, this number (Rthetha_ja) is specific to the application itself and we cannot do a general statement here.

This is why we did this application note, showing how to setup the thermal model and measure / calculate the thermal resistance of each node (e.g. ja an ca on bottom and top).

BR Travis

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