LM63615-Q1: Recommended value for the backpad soldering

Masaru Oinaga

Expert 4255 points

Part Number: LM63615-Q1
Other Parts Discussed in Thread: TPS7B84-Q1

Hello, Experts,

We have a question about the back PAD soldering joint area; Do we have a recommended joint area ratio excluding void?

Best Regards,
Masaru

over 1 year ago

0 Marshall_Beck over 1 year ago

TI__Mastermind 35210 points

Hi Masaru-san,

I am not familiar with the term you are using. Could you provide an illustration highlighting the specific geometry you are interested in knowing?

The solder stencil is provided in the datasheet. Does this cover your question?

0 Masaru Oinaga over 1 year ago in reply to Marshall_Beck

TI__Expert 4255 points

Hello, Marshall,

Please refer to the below diagram for where the customer is talking about:

For the green area i.e., PAD area, what is the recommended solder joint rate? For example, IPC-A-610 states that it should be >75% (=acceptable void rate <25%.)

Best Regards,
Masaru

0 Masaru Oinaga over 1 year ago in reply to Masaru Oinaga

TI__Expert 4255 points

Similar threads that I found for a different device:

For devices with PowerPAD like TPS7B84-Q1, the minimum requirement is 50%:
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1256499/tps7b84-q1-minimum-recommended-thermal-pad-soldering-joint-area-for-tps7b84-q1?tisearch=e2e-sitesearch&keymatch=Solder%252520joint%252520ratio#

Our customer considers WSON package (LM63615DQDRRRQ1) so would like to know in this case what would be the recommended soldering joint area rate is.

+1 Marshall_Beck over 1 year ago in reply to Masaru Oinaga

TI__Mastermind 35210 points

Hi Masaru,

Are you ultimately trying to know the acceptable void rate to determine how thermals would be impacted? I don't think we would have that data just like the other product line.

Our stencil guidance I gave you previously and here is guidance on the reflow profile for assembly accuracy.

https://www.ti.com/lit/an/spraby1a/spraby1a.pdf?ts=1712794945347&ref_url=https%253A%252F%252Fwww.google.com%252F

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LM63615-Q1: Recommended value for the backpad soldering