You have two choices when it comes to soldering in the two surface-mount ICs used in the Stereo Digital-To-Analog Converter described in the previous article: either hand-solder them or use a homebuilt reflow oven.
In the latter case, you’ll need to follow the instructions in the article titled “How to Solder Surface Mount Devices”, SILICON CHIP, March 2008. However, not many constructors will go to the trouble of setting up a homebuilt reflow oven unless they handle surface-mount devices (SMDs) on a regular basis.
Fortunately, hand-soldering fine-pitch SMDs only requires a few basic tools and a little care. At the very least, you will need a small temperature-controlled soldering iron, a magnifying glass (preferably a magnifying lamp), some desoldering braid (or solder wick) and a syringe of no-clean flux paste (Altronics Cat. H-1650). You’ll also need two pairs of tweezers, one straight and the other pair with angled tips.
Don’t try to attempt the job without these basic tools, otherwise you could wreck both the ICs and the boards.
It’s also vital to have lots of patience. You must treat each IC gently and avoid applying heat for long durations (more than 3-4 seconds at a time). The pins on TSSOP and SSOP devices are quite thin – in fact, they are noticeably easier to bend than larger surface-mount packages like SOIC/SOP (let alone DIP).
A temperature-controlled soldering iron is the best iron to use here. Set the temperature to somewhere in the 350-400°C range. The lower end of that range is appropriate when applying solder while temperatures around 400°C should be used when heating the solder wick, as described later.