Electronic – When using multiple capacitors for decoupling or bypassing, should they be placed as close as possible to each other

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It is often recommended to use multiple capacitors in parallel in bypass and decoupling applications, especially when working with frequencies above 50MHz.

There is some argument whether its better to use several of the same value capacitors or use capacitors of different values. Aside from that, is there any negative impact of placing the capacitors as close as possible to each other and the IC? Or should there be "some" trace between the capacitors?

Assume capacitor size are all 0603 or 0805. Is it better to place the capacitors side by side, or some alternate arrangement that leaves more trace between the capacitors?

Best Answer

Yes, but not necessarily. They should be placed as close as possible to the voltage input pin they are decoupling. The aim of this is to reduce parasitic ESR and inductance. Dave from EEVBlog does a great job explaining decoupling caps.

"EEVblog #859 - Bypass Capacitor Tutorial"