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MattChou
Associate
November 17, 2025
Solved

LDL40PUR Adjustable Voltage Setting

  • November 17, 2025
  • 1 reply
  • 117 views

Hi ST Micro,

Please send me the information for the adjustable LDO output voltage desgined from R1 and R2 formula.

Best answer by Peter BENSCH

Welcome @MattChou, to the community!

Unfortunately, the formula for calculating the resistors was not included in the data sheet. However, it is essentially the same as for many LDOs of the last few decades:

Vout = Vref*(1+R1/R2)+R1*Iadj

with Vref=1.2V (typ.), Iadj=0.5uA (max)

Hope that helps?

Regards
/Peter

1 reply

Peter BENSCH
Peter BENSCHAnswer
Technical Moderator
November 17, 2025

Welcome @MattChou, to the community!

Unfortunately, the formula for calculating the resistors was not included in the data sheet. However, it is essentially the same as for many LDOs of the last few decades:

Vout = Vref*(1+R1/R2)+R1*Iadj

with Vref=1.2V (typ.), Iadj=0.5uA (max)

Hope that helps?

Regards
/Peter

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MattChouAuthor
Associate
November 17, 2025
Thanks, Peter, it helps.
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