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TPS784: Find Value. (Resistor)

AndrewKim
Prodigy 170 points
Part Number: TPS784

Hi, 

I hope to use TPS78401DBVR IC for  power Source. 

R1 : Fix ! 

I want to know Vout= 1.2V , R2 ?  and  Vout = 1.8V ,  R3?  and Fixed R1 Value? 

Thanks 

Andrew

  • 0
    TI__Mastermind 18466 points

    Hi Andrew,

    Because you want to use an output voltage that equal to the bandgap voltage, you need to connect output directly to the FB pin to get a regulated output of 1.2V.

    For an output of 1.8v, using Eq 2 of the datasheet, you need a R1/R2 ratio of 0.5. an R1 of 10k and an R2 of 20k is fine. 

    Section 8.1.3 Output Voltage Setting (Feedback Resistors) on page 19 will be able to help adjust the values on R1 and R2 depending on what noise and quiescent modifications you need to make based on your application. 

    Best,

    Juliette