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SGarvey , 05-02-2021, 07:06 AM

I'm working on lesson five right now, though this came up in Lesson 4. The datasheet says to put the analog components on the bottom side and the power components on the top side. My first instinct is to put the decoupling caps such as C4 (VCC-GND) on the top side directly over the pins they are powering and run vias to right next to the pins. This would free up more space around our chip and let everything on the bottom side be placed closer.

Why did we not do this?

robertferanec , 05-03-2021, 02:53 AM

In this case "power" is more like about the components which are handling the high currents, not necessary components which are connected to power.

SGarvey , 05-03-2021, 06:23 AM

Fair enough.
The area directly above the chip does seem very empty, though. Would you consider it a mistake to put decoupling caps there? Why?

robertferanec , 05-04-2021, 08:47 AM

If possible, I prefer making direct connection between decoupling capacitor and the pad, than using a VIA.

PS: This video may help: Position of PWR and GND Planes in Your PCB Stackup Makes a Big Difference ... https://youtu.be/ELe1RNa-WC4