A (failed) experiment: I got 18F6621 samples from microchip.com (I LOVE these guys!!) and they are packaged in a TQFP64 package (a very dificult to use package if you are not a machine) so I decided to make a breakout box. Get those pins in pin header format so I can stick whatever I want to them. But I failed miserably. The design was haunted by the 8mil distance between the legs. It proved more (less) than my etching method could handle so I had heavy crosstalk between the leads.
And the soldering was no easy job too!!!!!
But if you feel adventurous, there are brd files you can use to despair on your own :)
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3 comments:
maby hard to get in the states, but try these:
http://www.sunhayato.co.jp/products/list.php?qry=0.5mmQFP
Less than $15 for most parts, make the work much easier.
I have two each of the following pic32MX360, pic32MX340, and dsPIC30FS011.
The trick to soldering these guys is sort of counter intuitive:
First, align and mount one corner pin. then the diaginal opposite corner pin. make any adjustments till it is perfectly aligned, then hit the other two corners.
Now, solder all the faces by loading the entire row of pins with solder. Make it nice and fat. You will bridge almost all of the pins with solder. (the counter-intuitive step)
Finally, put a piece of solder wick down, put your tip on top, and dab a bit of solder into the wick. Fresh solder on top will start it soaking up the solder underneath. Clean all the excess solder off the chip and board. You have to practice a bit to get a wavelike motion, like using a mop to clean the floor. Pull back from the pins, then dab forward into the next few, moving down the line, sucking up all the excess solder. Dabbing into the pins with the wick also insures that the solder has run under the pins (since you heat the trace as well as the pin).
You occasionally have to come down directly on top of the pins if you have some bridges that wont come clean.
I did 6 chips in about an hour this way.
I've found something similar on (...) ebay but was reluctant to use it. But since my miserable failure I think you present the only solution for test projects. Will try to get my hands on something like that! Thanks a lot!
That is a sexy board though...
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