Electronics > Beginners

Why am not able to get a grasp of PCB designing?

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redgear:

--- Quote from: ebastler on November 12, 2019, 11:39:55 am ---Quite a few of your ratsnest wires will be for GND connections. Not sure how KiCAD handles this, but I would create a GND layer early on to take care of these, to clear up the remaining picture a bit. You might even create a "temporary" GND layer on the top layer, such that KiCAD auto-connects all the GND pads and removes these ratsnest lines. (Eventually, you probably want your GND pour on the bottom, and most of the other connections on top. Then you will need to place vias near the SMD pads which need to be connected to GND.)

--- End quote ---

This didn't work. I tried creating a ground fill on the top layer but the ratsnets is still the same.


--- Quote from: jhpadjustable on November 12, 2019, 02:00:46 pm ---OP misspoke. It's not a SoC and it's not a microcontroller. It's just a switching converter with a lot more pins and power steering than one might be used to.

--- End quote ---
I might have been wrong but that is how the company calls it. Powerbank SOC. It has a boost converter, Charge Protocol Identifiers and a Battery Gauge built in.


--- Quote from: NivagSwerdna on November 12, 2019, 02:14:10 pm ---OK... I'll try and be a bit more constructive...

 8)

Looking at the datasheet and schematic suggests that you should (as some suggested earlier) forget about size constraints for now and work radially out from the chip.

e.g. the LEDs all need to live on the side nearest their pins, etc. and likewise each output should be put radially out from where they connect

... so put the chip in the middle and arrange the connections around them at an angle that reflects the majority of their connections.

You can then squish it together later

I would aim to route all non-ground nets first and come back to a ground flood later.

(The caps need to go where they are intended... so for example a decoupling cap should really be close to where it is meant to decouple... that can get lost in translation if you aren't careful)


--- End quote ---
Cool. Just arranging the components properly is difficult to me. There are some layout rules on the datasheet(that I don't properly understand) which makes it more difficult.

tautech:
Start again with a bigger PCB.
Drag all components outside the PCB margins.
Have the printed schematic handy or on a second display to constantly refer to while placing components.
Place first components that must be in a certain place. Lock them.
Then place the most complex components.
Slowly add other active components while still shifting already placed components to make room for passives yet to come.

As others have mentioned build and finalize circuit blocks of which you can select and move/rotate for best connectivity.
All the time you need consider how any and all components will be placed, soldered or reworked and routed.
Use autoroute often to see what you can improve with better placement then un-route and move/rotate stuff.

Study old commercial PCB's......lots ! Understand signal/data connections and power rail routing.
Use a pour to connect to as many components as you can, orientate them so that you can.
Eye up bigger components that might allow traces run under them and place them where this might help you.
Be prepared to spend real time on a good layout and don't be too impatient to do so.
After a couple of PCB's there'll be no stopping you and you'll spin them out in a fraction of the time your first one took.

Post your progress layouts for marking.  ;D

Daves good PCB guide:
http://www.alternatezone.com/electronics/files/PCBDesignTutorialRevA.pdf

More here:
https://www.eevblog.com/wiki/index.php?title=Online_Electronics_Tutorials_and_Books#PCB_layout_and_CAD

redgear:

--- Quote from: tautech on November 13, 2019, 05:52:03 am ---Start again with a bigger PCB.
Drag all components outside the PCB margins.
Have the printed schematic handy or on a second display to constantly refer to while placing components.
Place first components that must be in a certain place. Lock them.
Then place the most complex components.
Slowly add other active components while still shifting already placed components to make room for passives yet to come.

As others have mentioned build and finalize circuit blocks of which you can select and move/rotate for best connectivity.
All the time you need consider how any and all component will be placed, soldered or reworked and routed.

After dinner I’ll be back with a link to a good and full guide.

--- End quote ---

Tried it, as all connections just go to a single IC it is very difficult for me.
Thanks, I will be waiting for the link.

redgear:
I have disabled ratsnet right now and started grouping components as per the schematic. Will post it once i am done for review

james_s:
Maybe try some simpler PCBs first to get the hang of it? Lay out some stuff like 555 and transistor multivibrator LED blinkers, op-amp circuits, just easy stuff with a handful of components. Once you get the hang of the process it gets easier.

Some people are also just better at visualizing spacial relationships, PCB layout came quite naturally to me but I've seen a lot of people struggle with it.

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