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Electronics => Electronics => Topic started by: benji on March 16, 2008, 09:08:22 AM

Title: ATmega128 TQFP misery
Post by: benji on March 16, 2008, 09:08:22 AM

hey folks, finally i setteled upon this processor, prblem is that its package is very thin and sensitive that i dunno how to solder it
, what do you guys do for soldering such a micro????

i thought of buying a socket but i couldnt found one in my area, plus the socket costs a freakin fortune

Title: Re: ATmega128 TQFP misery
Post by: Steel_monkey on March 16, 2008, 09:58:08 AM

As I remember, Atmega 128 has 0.8 mm pitch. This pitch can be relatively easy soldered by hand with conventional soldering iron. The thing is, liquid flux is required to prevent bridges. Put some flux on PCB and also wet chip before soldering. I personally use old colophony-alchohol mixture, it works very well. I also use soldering iron with flattened screwdriver-like tip (it is really destructive to the tip and iron, but it is not the case when it costs 3 $). After installing and positioning chip at the PCB, hold it when soldering. I personally use tweezers.
Also solediring something useless with same pitch before atmega will help.
There are pictures of my ARM PCB somewhere here. 0.5mm pitch on poorly - made DIY PCB  ;D , but works fine.

Title: Re: ATmega128 TQFP misery
Post by: dunk on March 16, 2008, 11:52:24 AM

i was in exactly the same position a couple of yeas ago.
the only real way forward once you start needing to use surface mount components is to start making your own PCBs.

if you have access to a laser printer then i recommend searching for the "toner transfer" method of PCB making.
0.8 mm pitch components are easily usable with this method.

dunk.

Title: Re: ATmega128 TQFP misery
Post by: benji on March 17, 2008, 06:04:23 AM

i asked about this thing and i found a place that solder these packages using hot air,
no idea what is that , although im glad i found a way to solder this thing

Title: Re: ATmega128 TQFP misery
Post by: JonHylands on March 17, 2008, 06:43:37 AM

I made a reflow oven to do my own surface mount soldering.

http://www.huv.com/blog/2007_03_01_archive.html

My mini-sumo Seeker 2x uses an ATmega128...

http://www.huv.com/miniSumo/seeker2x/

- Jon

Title: Re: ATmega128 TQFP misery
Post by: Admin on March 17, 2008, 07:32:57 AM

Please do not double post:
http://www.societyofrobots.com/robotforum/index.php?topic=3519.0

Title: Re: ATmega128 TQFP misery
Post by: benji on March 17, 2008, 10:33:29 AM

sorry for double posting i didnt notice it
anyways feel free to delete a post if its doubled