FEDEVEL
Platform forum

wenyuan , 08-27-2024, 03:40 AM

How many decoupling capacitor and bypass Cap we need in power rail near the ic
And what value do we need

Robert Feranec , 08-27-2024, 04:45 AM

https://youtu.be/ARwBwHZESOY

wenyuan , 08-28-2024, 04:16 AM

There is no direct answer to my question ❓❓❓

wenyuan , 08-28-2024, 04:16 AM

In your video

wenyuan , 08-28-2024, 04:16 AM

I mean hardware design, not pcb layout design

Robert Feranec , 08-28-2024, 06:11 AM

smallest footprint with biggest value, that is the answer from the video. everything else is based on optimization e.g. price, size, etc ... I believe in your picture they fitted the largest capacitor with biggest value, if you can fit that value into do smallest footprint, you don't need three of them.

QDrives , 08-28-2024, 08:12 PM

As with about everything in electronics: no, there is no direct answers. Just about everything depends.
Depending on many things too. For your decoupling capacitor for instance:
- The voltage drop that is allowed
- The impedance of your PDN
- The smallest side component that you use
- etc.