Hacker News new | ask | show | jobs
by Kirby64 50 days ago
> 100 nF ceramics are fine, but you may actually need a 100 nF and a 10 nF side-by-side because of that inductance depending on how dirty your power line is.

Capacitance value is essentially irrelevant to inductance. The thing that dictates inductance of a decoupling capacitor is essentially only the package size. The way to fix that is to use smaller (physical) sized components. The only reason it may be related is that some larger values of capacitance physically can't fit into tiny package sizes. For 100nF, you have essentially no restrictions though. 0201(i) are easy to find in that value.

1 comments

That's fair, I was thinking of hole-through components and I should probably stop doing that in 2026... But: if we're being pedantic: it isn't the physical size as much as it is the loop area that the current travels through, and that doesn't depend so much on the size of the package as on how the package is constructed. Low ESR caps such as IDC or LGA type caps will do better than other types even if the physical size is identical. Lead length also still matters, whether physical leads or length of the traces connecting the cap to the device and these should be kept as short as possible.