FEDEVEL
Platform forum

, 08-20-2019, 05:05 AM

sir i confused with decap placement any ref video and suggestions.

robertferanec , 08-21-2019, 05:23 AM

Guest, please always create new topic for different subject. I moved your post here.

To answer your question:
- simple answer is, that in most cases you may want to place decoupling capacitors as close to the power pins as possible. If you are not sure, have a look at reference design. Ideally you may want to have at least 1 decoupling capacitor per power pin (however this is not always possible).

PS: In some articles you will find people saying, that decoupling capacitors do not need to be placed close to power pins, however if you do not know how far they can be, just place them as close as possible.

Paul van Avesaath , 08-21-2019, 06:13 AM

again like most of hte post lately, read the datasheet of the memory chip you are using.. there are recommendations for this. also example layouts..
the perfect world = every pin has their own bypass cap. real world = place them as close as possible.. also when power is comming from a dedicated powerplane, it usually is enough to have them connected to that plane and placing them on top and on bottom next to the memory chip.. take special care of reference voltages they should always have dedicated bypass caps only for that pin.