LM5000: Datasheet's schematic VS Webench's schematic? which one is the best

Gabriel Boucher

Prodigy 20 points

Part Number: LM5000

Hi,

I'm planning to use the LM5000 to generate 48v from a 16v source.

The Webench calculator gives me different values than the Datasheet's schematic.

Which schematic do you recommend? (image in attachment)

Thanks

over 2 years ago

0 Richard Fu22 over 2 years ago

TI__Mastermind 21410 points

Hi Gabriel,

The expert for this part is currently out of office due to holiday. It is possible you have different schematics due to different input voltage conditions.

Regards,

Richard

0 Gabriel Boucher over 2 years ago in reply to Richard Fu22

Prodigy 20 points

Hi Richard,

no the Input voltage condition are the same.

What strikes me the most is the difference in value for the inductor (33uH to 470uH).

thanks

0 Niklas Schwarz over 2 years ago in reply to Gabriel Boucher

TI__Mastermind 21270 points

Hi Gabriel,

Thanks for reaching out.
I entered the values from the datasheet example into webench and got the same result.

If recommended values vary strongly between datasheet and webench, I would always recommend to go with the datasheet examples first. The schematics suggested there are verified and tested, while the webench examples are based on calculations only.

In addition, 470uH seem rather high for this Boost converter running at minimum 300kHz switching frequency, so a smaller inductor should be fully sufficient. The datasheet features a chapter about Inductor Selection as well (page 12), which is useful for calculating the minimum inductance for additional reference.

If you have additional question, please let me know.
Best regards,
Niklas

0 Niklas Schwarz over 2 years ago in reply to Niklas Schwarz

TI__Mastermind 21270 points

Hi Gabriel,

I hope you made progress in finding a suitable circuit.
As there has been no further comments, I will close this thread for now.
If you have additional questions, please reply below to re-open the thread.
Otherwise feel free to click the "resolved" button.

Best regards,
Niklas

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LM5000: Datasheet's schematic VS Webench's schematic? which one is the best