Surface mount soldering a PQFP

Discussion in 'General Electronics Chat' started by fastwalker, Oct 10, 2010.

  1. fastwalker

    Thread Starter Active Member

    Jun 24, 2009
    Hi All,

    I want to build a circuit that has a 208 PQFP package microcontroller. Is it actually possible to hand solder a surface mount chip like this these days? I remember about 15 years ago we used to hand assemble some surface mount boards by applying some solder paste to the PCB, carefully placing the SMT chip on the board then using a small heat gun to melt the solder. This was with smaller chips however that I think had a larger lead pitch.

    So can you actually hope to mount a 208 pin PQFP by hand these days, and if so what tools would you need?

  2. PackratKing

    Well-Known Member

    Jul 13, 2008
    Depends......what is the pitch of your chips "legs"

    In 35mm SLR cameras, both film and digital, dwell some of the most stinkin' small chips, on a substrate of either mylar or polyamide, aka Kapton.......I had to develop the tools to solder them, or lose a whole lot of good paying work.......guess which way I rolled. :D

    It is possible to hand solder 40 pins / inch without bridging or heat damage to the chip / substrate, and solder paste is not the answer....... details upon request.
  3. ke5nnt

    Active Member

    Mar 1, 2009
    You might be able to get EXTREMELY lucky and do it with a very fine tip on a professional solder station like a weller or the likes, but it'd be difficult. There are a number of tools for soldering very small parts like this, of which include:

    Microscopic soldering:

    Education related to SMT soldering: Cost SMD Soldering Guide.pdf

    Soldering Pots:
  4. DonQ

    Active Member

    May 6, 2009
    You might find some help at:

    I didn't see anything as high as 208, but they do have 100. Perhaps you could talk to them, or at least get some ideas from their technique videos. They use an extra deep solder mask to make placement and soldering of the leads easier.

    Their multi-package designs have a little problem with the ground pad of PQFP wanting to short across the trace extentions for the smaller packages. I did a PQFP-80 by cutting and lifting off the internal portions of the traces. Using their product also required my drilling a hole and putting a small length of copper rod in place for the heat transfer from the thermal pad on the chip.

    Anyway, some good info there for what I think you're trying to do.