# Confusion about feedback resistor values for buck converter

I'm making my first voltage regulation first with a buck converter, but I'm having some trouble making sense of the following datasheet. https://www.ti.com/lit/ds/symlink/tps560200.pdf

So I've made the circuit with the recommended components values given in Table 2 in section 8.2.2.2. Now I expect the table to give me the right results, but I did also gave equation 2 a try to calculate the R2 value.

I want an output of 3.3V, and I use the 20kΩ as recommended in the table for R1. This makes me end up with R2 needing a resistance of 6400Ω (=20000*0.8/(3.3-0.8)), but if I compare that with the 61.9kΩ recommended, then I get really confused as to how they arrived at those values, as those two values are nowhere near each other. Also, the equation of R2 seems to be inverted proportional to the values recommended in the table.

I would really appreciate an answer on what I'm doing wrong, as I, by default, assume I am as it's my first switching voltage regulation design.

• Table is correct, equation mixed up R1 and R2. Aug 7, 2022 at 20:57
• Well spotted @LarsHankeln. Thank you! Aug 7, 2022 at 21:01
• @techbech You can also try www.syncbuck.com to calculate standard divider resistor values. Aug 7, 2022 at 21:19

Basically -- make the voltage divider that feeds the $$\V_{sense}\$$ pin such that $$\V_{sense}\$$ sees 0.8V when the output is what you want.