GND on bottom of PCB


#21

Your drawing does not show a suggested layout, only the schematic. Everything i posted does use the same schematic as your image.


#22

Hi R,
I’m a bit puzzled! I agree, my drawing is the same as the ones in your PDFs, but I have place the XTL and Caps in the same way as both, haven’t I?
C.


#23

Running traces to the gnd pins on the chip kind of defeats the purpose of using a gnd plane to reduce gnd noise. On my SMT ground pins I right click on the pad and open the pad editor. I change the “pad type” to “thru hole” and do a minimum drill size(OSHPark recently lowered the min to 0.01inch. or 10 mils). On the “Load Clearance and Settings” tab I change the “pad connections” to solid.


#24

I would say it is easier (and saver) to place a via instead of editing the footprint.


#25

Hi P,
My purpose of using a GND plane is to avoid adding tracks to both sides of the board, but it’s working, as I route the GND on reverse and don’t need to etch so much copper. (I have lots of double sided boards!) I CAN SEE THIS IS NOT SENSIBLE!
I’m not so good at using Kicad, and kind of cheat, instead of learning the system, properly. Having said that I learn as I go along. I also get reminded of things I had forgotten over the years, such as global tracks etc, which I used for my latest board.
I’m sure I will soon improve my methods, and catch up with some of the slower Kicad uses among you.
Thanks, C.


#26

Via in pad usually increases the cost of the board significantly when being made by a fab, but he is home-etching this board and therefore avoiding vias as much as possible. Otherwise I would agree with @Rene_Poschl and add vias next to the gnd pads under the component. The additional costs of using via in pad is usually only practical for high density boards in high volume production.

Global tracks?


#27

Hi P,
Global tracks?
On PCB> Design rules> Global design rules> Custom track widths> (Set your own size, for adding as you need)
C.


#28

A copper pour on a layer with signal tracks is pretty useless for anything above audio frequencies, and may cause severe EMI and performance issues if it’s your only means of connecting ground throughout your circuit. What you need is a solid, unbroken ground plane in an inner layer just under the signal layer, i.e. you should use a 4-layer board. Drop vias to the ground plane near any points needing a low-impedance ground connection, especially IC ground pins, decoupling capacitors, oscillator capacitors, etc. You can keep the top layer copper flood if you like, but it’s the ground plane you really need. Copper pour ≠ ground plane.


#29

Hi J,
I wanted to do two things at the same time: learn how to make a ZONE and use it to route one important track that wouldn’t allow me to use a single layer, I chose GND.
As mentioned I was fiddling/kludging to make the circuit work, with incompetence.
Thanks, C.


#30

That’s cool. I was just trying to give you pointers that may help in your quest to “make the circuit work” :slight_smile:


#31

Has anyone seen a board being fabbed? The they do the plated holes before the etch so they can electroplate all the holes at once by applying a different voltages to the two sides of the copper clad panel. All my method does is add a drill hit in plated hole part of the drill file. No other fab file changes, None. It’s not my idea. I have seen it done on commercial boards.


#32

We are not worried about the pcb fabrication part of your workflow. We are worried about reflow soldering of pads with drills in it.
It is also more work then simply putting a via there. (Especially if you ever need to update your placed footprints from the library. Then you loose your work if you have a via there it stays where you put it.)


#33

Not you it would seem.

Just to be clear, this process is only applicable to double sided boards.

Not only would this strip the copper from one side and deposit it on the other, but the holes are first filled with carbon thereby forming connections between the two sides of the board which would result in not electroplating anything at all, at least not until you burned out all the carbon. The entire board is at the same potential, it is the cathode. The tank walls or another anode in the tank, is at the other potential.

10 mil is still pretty big for via in pad. The OP’s pads are not that fine pitched but are still less than 14 mil wide.

Your suggestion is only applicable to double sided boards, but double sided boards are generally not used for anything that would be considered “high density” so there would be very little need for via in pad in the first place. As has already been said, if the op wasn’t home etching/drilling his board then adding vias to the ground plane would have been recommended, but he has plenty of room to add them without resorting to via in pad.


#36

The board looks amazing for a first try. Another couple of nitpicks. Kicad uses front and back for the two layers, not top and bottom. The copper zone is the boundary of a copper fill, not the actual fill. Have fun.


#37

Hi P,
I’m happy for nit picking if it points something out.
Copper fill actual fill? I’m sure I’ll find out the more I try it.
Last time, I fond I could add tracks inside the GND ‘fill’, which pleasantly surprised me.
C.


#38

Good catch.

Post needs 20 characters.


#39

Hi,
I’m trying to understand how [EDIT electroplating] would work. I imagine, that the copper being transferred would find the best path and build up from there, so perhaps a thread at first building up to a fat thread.
C.


#40

Hi,

Previously I made a ground zone with PAD connections of thermal relief, and now I prefer solid. How can I edit them please?
C


#41

Normally in the zone properties dialog. (left click on zone outline and then press e, or right click on the zone outline and then select properties.)

This works unless your pads or footprint settings overwrite the zone setting. If that is the case then you need to edit the footprint or pad settings to say: connection from parent.
Report back if changing the zone setting does not do it, then i will post screenshots on how to edit the footprint stuff.


#42

Hi R,
I re-watched a ZONE instruction video and did it ok, although I couldn’t tell by looking at the PCB till I exported an SVG and it showed.

I actually deleted the ZONE and re- did it, althougfh earlier, I may have done it ok, with the EDIT.

Thanks, C.