Decoupling Capacitor Calculator
Calculate the minimum decoupling capacitance needed to limit voltage droop during a transient current spike.
A
µs
mV
Minimum Capacitance
50.00 µF
Minimum Capacitance (nF)50,000 nF
Charge Needed5.00 µC
Minimum Capacitance vs Transient Duration
Decoupling Capacitor Sizing
Formula
C = I x dt / dV
Where I is the transient current, dt is the duration of the transient, and dV is the maximum allowed voltage droop. Place decoupling caps as close to the IC power pins as possible.
Example Calculation
0.5 A transient for 10 us, maximum 100 mV droop.
- 01dt = 10 / 1000000 = 0.00001 s
- 02dV = 100 / 1000 = 0.1 V
- 03C = 0.5 x 0.00001 / 0.1 = 0.00005 F = 50 uF
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