LM60430: How do you deal with solder paste leakage on thermal vias under the IC from the PowerPad.

Samuel Freal

Part Number: LM60430

Tool/software:

Hello,

We are currently experiencing problems when testing our boards with the LM60430DRPKR buck, on some of which the output voltage is not as expected.

We suspect that this is due to a problem with the soldering of the BUCKs, caused by the solder paste leaking through the thermal vias of the thermal pad (we've been able to verify this by properly rebrazing the defective BUCKs).

What do you recommend to prevent solder paste leakage ?

Thanks in advance

Samuel

6 months ago

0 Andrew Kutzler 6 months ago

TI__Mastermind 23795 points

Hi Samuel,

I would recommend avoiding using vias where the device is being soldered to. Solderpaste can leak through the board and cause issues. If this cannot be avoided then, I would ask your PCB vendor what the smallest via size they can support.

Thanks,

Andrew

0 Samuel Freal 6 months ago in reply to Andrew Kutzler

Prodigy 30 points

Hello Andrew,

In our case, with the LM60430DRPKR, TI recommends those vias for thermal dissipation as you can see in the image below :

Do we have to plug them up, or put a savings varnish on the bottom face, which is the preferable solution for a reliable soldering process ?

Thanks

Samuel

0 Andrew Kutzler 6 months ago in reply to Samuel Freal

TI__Mastermind 23795 points

Hi Samuel,

Are you tenting the Vias? I don't seem to run into issues when I do that.

Thanks,
Andrew

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LM60430: How do you deal with solder paste leakage on thermal vias under the IC from the PowerPad.