Mixing THT and SMD on single board

Hi everyone, new to Kicad, and to the forum. Since I started a month ago, I have
a finished pcb. But before I generate the gerber files / drill files required for manufacture,
I just wanted to check with all of you if a board which has a mixture of THT and SMD
components will present any special challenges for manufacturing? I had to use a
micro-hdmi connector, which was available as a SMD component.
Specifically, 1) is mixing THT and SMD on one board possible from the mfg. perspective?
2) any special design restrictions on track size/seperation etc?

There should not be any issue at all; as this is actually fairly common practice for a variety of reasons.

If you want a better understanding I’d suggest looking up PCB manufacturing at the University Of YouTube. I’ve watched a few myself to get a better understanding of what they do after the files are sent to them.

On Edit: A good example is the Arduino UNO board.

oh ok, thanks. I am a full time student at the UoYouTube :slight_smile:
I just wanted to get a more informed view on low volume
manufacture. Thanks, your reply helped.


Good catch.

PCB manufactures don’t really care if the finished “assembly” is going to have one, or both, of the technologies.

ASSEMBLY houses, however, do care if some parts REQUIRE hand placement/soldering, or both.

1 Like

Thanks your your replies. I will keep you posted as I trudge ahead with my design…

  1. This is done all the time.
  2. Talk to whomever will make your PCB.
    Is this automated high volumes, or hand placed, paste screened and reflow or hand assembled, manual solder ?

With some care, paste-thru-hole is also possible.
Connectors like USB & HDMI may have SMD pads + Pins for strength, but are SMD in handling.
Paste masks usually put paste into the Pin’s holes/slots, as well as on the SMD pad areas.
Such connectors may have keep-away areas under them, which should show on the footprint drawings.

1 Like

It used to be common on volume products like CD players, to find SMD on the underside of largely THT boards, all wave soldered.

1 Like

Good point, in that case the plots may need to include glue dots… or the assembler may generate those themselves, ergo … ask the assembler what they need

1 Like

You had to work closely with the assembler with wave solder, as the wave direction becomes critical

1 Like

Really appreciate all the replies. I want to do the wave solder myself. Currently I have put the footprint
for the HDMI micro with just the pads. Since this device has 2 rows of pins with the second row recessed
from the front row, the only option for routing that I had was to pull tracks towards the no-go zone, and drop
vias to the bottom layer for onward routing. (top layer is the component layer, and pad spacing does not permit
routing tracks from the rear pads out to the front from between pads.
I would want to send some pictures when I reach work, so that people can get a better look at it and comment on
my strategy for routing, too. (should that be a different thread in a different section of this forum?)


I’m 100% certain you don’t want to do the wave-soldering yourself as otherwise this thread wouldn’t exist :wink:

sorry, got the terminologies mixed up… I meant reflow.

Created new thread on Layout.

Did you really mean “do the wave solder myself”, or just mean assemble prototypes yourself ?
The part you describe does not even sound very wave solder compatible, sounds more like reflow (paste and reheat)?

Fortunately the use of SMD wave soldering has become obsolete, it was a stop gap when through hole was still the dominant technology. Wave soldering with lead free solder is too stressful on the components.

I think you can go straight to the board manufacturer and they will teach you. You can pretend to be a customer and ask him some questions like: I need to mix THT and SMD on a single board, can you do that? How is it done? He will give you knowledge without reservation, which I do often.
Here I will introduce these two websites for learning pcb knowledge.
Hope can help you.

(Moderator edit: commercial link removed, and old revived thread will be locked.)

This can have a lot of pcb basics