Worst Case Pad to Thermal Pad Distance

Aferdita Zogaj

Part Number: LM5155

The package outline of the LM5155 shows that it is package DSS0021B (WSON).
It can be seen that in the worst case calculation the distance pad to thermal pad = 1/2 * (1.9 - 1.1 - 2*0.35) = 0.05mm.
How can this be?

over 1 year ago

0 Bryan Radix over 1 year ago

TI__Expert 3260 points

Hi Aferdita,

Thanks for reaching out. I'll get back to you later today with a response.

Thank you and best regards,
Bryan

0 Niklas Schwarz over 1 year ago in reply to Bryan Radix

TI__Mastermind 29900 points

Hi Aferdita,

Sorry for the long delay on this.
I am not sure if I fully understood the question.
The last section of the datasheet describes measurements and sizing of the WSON package.

Did you find any error within these specs or is the question referring to something else?

Thank you very much for clarifying.
Best regards,
Niklas

0 Aferdita Zogaj over 1 year ago in reply to Niklas Schwarz

Prodigy 10 points

No i didnt find any error's i was just wondering if the minimal distance pad to thermal pad really equals 1/2 * (1.9 - 1.1 - 2*0.35) = 0.05mm.
If this is the case i am unable to use this Chip due to the design clerance of 0.15mm.

0 Brigitte over 1 year ago in reply to Aferdita Zogaj

TI__Guru 65180 points

Hello Aferdita,

In theory you are right, but to be honest, I expect that the thermal pad and the rest of the package should scale the same way.

Best regards,
Brigitte

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Worst Case Pad to Thermal Pad Distance