DP83TD510E: Are vias needed in the thermal pad for heat sinking?

Cyrus Kelly

Part Number: DP83TD510E

Hello,

I'm using the DP83TD510E. The datasheet has an example layout footprint that includes 5 vias in the thermal pad. Is the thermal pad needed for heat sinking? Do I really need the 5 vias shown?

I know the thermal pad is required to be soldered to GND as it is the only GND connection on the chip. The datasheet says, "vias are optional depending on application, refer to device data sheet." Not very helpful.

Thanks,

Cyrus

over 4 years ago

0 Cyrus Kelly over 4 years ago

Prodigy 240 points

Also, if the thermal pad is needed for heat sinking, please provide guidance about how much copper pour is needed (either in an internal ground plane or on the opposite side of the PCB).

Thanks.

0 Gerome Cacho over 4 years ago in reply to Cyrus Kelly

TI__Mastermind 44285 points

Hi Cyrus,

We do recommend the 5 vias on the GND pad. As to guidance regarding the size of pour, we do not give recommendation as that is dependent on many other factors from a manufacturing and design standpoint.

0 Cyrus Kelly over 4 years ago

Prodigy 240 points

Hello Gerome,

OK. Can you provide the PCB construction details that were used to determine RθJA (e.g. When surface mounted to an FR4 board using 0.5 sq in pad size.)?

Best regards,

Cyrus

0 Gerome Cacho over 4 years ago in reply to Cyrus Kelly

TI__Mastermind 44285 points

Hi Cyrus,

These thermal parameters were not characterized via PCB validation, rather via simulation.

Sincerely,

Gerome

0 Cyrus Kelly over 4 years ago in reply to Gerome Cacho

Prodigy 240 points

Hello Gerome,

Understood. What PCB construction details were used to determine RθJA in the simulations?

Thanks,

Cyrus

0 Gerome Cacho over 4 years ago in reply to Cyrus Kelly

TI__Mastermind 44285 points

Hi Cyrus,

Hopefully this sheds some light. This is from the hyperlinked footnote on the thermal information in the datasheet.

Sincerely,

Gerome

0 Cyrus Kelly over 4 years ago in reply to Gerome Cacho

Prodigy 240 points

Hello Gerome,

No, it just says that the thermal parameters are dependent on the PCB used during the test. That is exactly why I'm asking for what the simulation you used assumed about the PCB characteristics. In order to judge how my PCB will perform, I need to know what assumptions were made about the PCB for your simulation.

Cyrus

0 David Creger over 4 years ago in reply to Cyrus Kelly

TI__Mastermind 29192 points

Hello,

Gerome is currently on vacation. Please expect a response next week. Thank you for your understanding.

Sincerely,

David

0 Gerome Cacho over 4 years ago in reply to David Creger

TI__Mastermind 44285 points

Hi Cyrus,

Simulations typically use a JEDEC standard 2s2p thermal test PCB in a natural convection environment.

Sincerely,

Gerome

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DP83TD510E: Are vias needed in the thermal pad for heat sinking?