Re: [SI-LIST] : deCoupling caps and there placement

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From: Chris Padilla (cpad@cisco.com)
Date: Fri Nov 10 2000 - 17:06:36 PST


Inductance is the main limiter of a capacitor's bandwidth. Longer traces
have more inductance than shorter ones. Also, keep the ground and power
vias of the cap close together to reduce the loop inductance. Finally, put
the cap, in the configuration I've described, as close as possible to the
chip you are intending to decouple.

----->Chris

>I just heard a school of thought that says place decoupling caps
>physically as close as possible to GND pins....I have always keep the
>lead length as short as possible to the VCC pin which decouples the
>power pins. I understand that one should keep the ground lead as short
>as possible also ... so if one has a trade off to make , which lead
>should be longer and why...??? any thoughts
>
>keith
>DIGITAL NETWORKS

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