Re: small soldering job

"Spehro Pefhany" <speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:g1kd915iplq6cdsd03uq2upeig2kqkmkc5@xxxxxxxxxx
> Hot air works okay for them too, at least for a few prototypes. I have
> not tried a QFN44 or 28 yet, but they don't look too scary.

I'm assuming we're all talking about the same thing, chips with a heat-sink
pad in the center that is intended to be soldered directly to a pad on the
component side of the PCB, that in turn is connected with thermal vias to
more copper on the other side of the PCB. The problem being that the pad is
between PCB and chip, and therefore not accessible.

How do you get solder to the hidden pad? And, are you applying the hot air
from the component side or the other side?

I like Paul's idea of leaving a hole big enough to get the solder in from
the bottom.


.

Relevant Pages

  • Re: small soldering job
    ... >> Hot air works okay for them too, at least for a few prototypes. ... > pad in the center that is intended to be soldered directly to a pad on the ... > more copper on the other side of the PCB. ... > I like Paul's idea of leaving a hole big enough to get the solder in from ...
    (sci.electronics.design)
  • Questions on PCB terminology
    ... Hi there - I've been running across a lot of PCB terminology lately, ... NSMD means that the hole in the solder mask is ... mask is smaller than the copper pad. ...
    (sci.electronics.design)
  • Re: DFX to Gerber?
    ... You can drill that by hand no problems, probably take 15 to 20 minutes. ... To line up the two sides print to overhead film on a laser and lay them back to back, line up the pad holes and run some tape down the side of the two overhead films. ... Have the taped bit an inch or two from the edge of the pcb to minimise the error due to the thickness of the pcb that will be placed between them. ... They make it easy to solder both sides if needed and also for fault finding/debugging. ...
    (rec.crafts.metalworking)
  • Re: DFX to Gerber?
    ... You can drill that by hand no problems, probably take 15 to 20 minutes. ... Get some HSS 3mm shank pcb drill bits and whack them in the drill press ... Increase pad and track sizes as much as practical - makes it more robust ... Or hand solder both sides of every via? ...
    (rec.crafts.metalworking)
  • Re: plastic flat-packages with 0.5mm pin spacing (was Cantaloupes)
    ... Put a little dab of paste on the center pad (not too much or you will have ... that happens), place the part, reflow it using hot air, and make sure it's ... solder the pins by hand. ...
    (sci.electronics.design)
Loading