LM5123EVM-BST: How to change output voltage

Masaru Oinaga

Part Number: LM5123EVM-BST

Hello, Team,

We would like to set Vo to 36V or 48V using LM5123EVM-BST.

Assuming that changing RFBT and RFBB would do, but Vo only went up to 30V (w/o load) after changing R24 = 21kOhm and R26 = 4.7 ~ 36kOhm.

Where do we configure the output voltage setting?

Best,

Masaru

0 Stefan Schauer over 2 years ago

Hi Masaru-san,

you are right this are the correct resistors. See also datasheet section 8.3.7. and also consider 8.3.4.

with your selected values the max output voltage is:

21k /( 21k + 4.7k) *40 = 32.6 V

So you may have to further decrease R26. But also ensure when starting that R24 + R26 are less then 35k.

Best regards,

Stefan

0 Stefan Schauer over 2 years ago in reply to Stefan Schauer

Hi Masaru-san,

did you get all the required information, so that we can close this thread.

Otherwise just let me know.

Thanks,

Stefan

0 Masaru Oinaga over 2 years ago in reply to Stefan Schauer

Hi, Stefan,

Sorry for the late response.
The issue is resolved, so let me close this thread.

Thanks,
Masaru Oinaga

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