[sdiy] Hand soldering TQFP packages

[Paul Maddox]

Peter,

> You only need a normal (not SMD) soldering iron - but also a SMD one can 
> be
> used.
> The important part is a special flux paste: RMA 04-HV (Stannol and other
> companies have it).

I did it at work (www.QinetiQ.com) yeah, I had all the right tools and 
solder flux :-)

> - First you have´fix the IC on two edges (no matter if you connect some 
> pins
> together!) - just be sure to fix the part on the right place.

yep, two opposite corners.

> - Then put a the flux paste on all end of the pins (the end of the pins 
> and the
> rest of the copper needs the paste).

yep.

> - Take your soldering iron (temperature a little bit higher than normal - 
> 380
> degrees celcius are ok) and start from one corner (but not one of the two
> corner where you fixed the part!) and deliver enough solder and move with
> constant speed over all pins on that side to the end of the row.

yep.

> The fluc paste garantees that the solder can flow under the pins AND that 
> the
> excessive solder flows back to the soldering iron and so to the next pins. 
> When
> the soldering iron leaves the pin there is normally no bridge between pins 
> and
> you get very nice soldering joints!

Yep, the problem is the solder paste dries pretty quickly, I also had 
problems with the device not 'quite' lining up with the PCB, I suspect the 
PCB tolerance wasn't quite spot on (well, it was cheap) and hence I had to 
install the chip slightly 'skew' to get the best connections I could, but it 
did mean that I had some slightly exposed pads, and hence, some bridges..

Paul