DC-DC feedback resistor calculator
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Converter feedback divider
Results
Divider ratio (R1/R2)
Vout/Vref − 1
Lower resistor R2
Standard value picked from 1 k–100 k
Upper resistor R1 (exact)
R2 × (Vout/Vref − 1)
Upper resistor R1 (E24)
Nearest standard E24 value
Feedback current
Vout / (R1 + R2)
Divider power
Vout² / (R1 + R2)
Ratio R1/R2 = 3.13 (target 3.13)
About the divider
Feedback dividers sit between the output rail and the regulator's Vref pin. Keep R1 and R2 in the 1 k–100 k range: too low wastes power and loads the rail, too high lets noise and the reference input leakage skew the set point. The E24 proposal shows the standard-value option plus its percent deviation from the exact resistance, so you can judge whether the nearest E24 pair is close enough or should be fine-tuned with a second resistor.
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