Q: TPS63030 FB pin resistor values by 1038028

Hi

Customer sees note in d/s page 14 - "it is recommended to keep the value of this resistor (R2) in the range of 200k"

Customer has used lower values for R1 and R2. E.g. he has used 1k for R2 and 4k for R1. Vout=2V5 in this case. He asks are these low resistor values ok?

(He and I think it is, because normally the problem is if you have too high a resistor value, but due to the precise wording of the d/s we need to check)


A: Re: TPS63030 FB pin resistor values by 1090425

This is ok.  His light load efficiency will be much worse as he is burning 200 times as much power in the FB divider. 

If he is using a Cff (feedforward cap), he should increase is proportionally to the decrease in R1.  So, if R1 were 200k and Cff were 10pF, now Cff should be 500pF with R1 = 4k.