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Soldering TQFP -- The big problem

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NikZetaJones

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tqfp soldering

Hello,
I bought 2 ATmega128 that comes in 64 pins 0.8mm pitch TQFP package. Does anybody can give me some hints in soldering this kind of packages?
Thanks
Ezequiel
 

kendr

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soldering tqfp

Hi,

The easiest way would be to drag solder the ic.
- Use flux to coat all of the ic's pads on the pcb.
- Place the IC on the board on top of the flux
- Put some solder on the tip of the soldering iron and drag it across the
ic pins. The flux wil ecsure an even spread of solder over the tqfp pins

hope this helps
 

NikZetaJones

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lqfp soldering

Is there any way I can download that files with D*A*P? I have dial up, and it's slow and I cannot resume.
Thanks
Eze
 

Beepster

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qfp soldering

I use 10-30x zoom stereo microscope. Use plenty of fresh liquid rosen flux. Use .254mm solder. Align & solder one corner, then the oposite corner. Don't let the flux dry or it will not work well. Get a bit of solder on the iron tip and slide it on the pcb into the edge of the pin, the solder will flow onto the pin/s. The flux if it is wet will prevent solder bridging.
If you get bridging use solder wick (wire braid) to remove the bridge, use fresh flux. Do not let the solder on the iron tip get old, must be melted not longer than 1-2 seconds.

Remove the flux soon after soldering.

Good luck !
 

Jayson

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soldering qfp

How do you remove the flux? I have a flux dispenser pen that I use to apply to the board before component placement, but how can you remove the flux afterward, since the componenet is covering it?

- Jayson
 

sgrudu

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hand solder tqfp

Eh eh, the application note from the link above
(from cygnal.com) is identical to the article
published in CIRCUIT CELLAR #142, MAY 2002
pointed by ZeRoN.. In fact, reading from the article
you see that the author works for Cygnal :)
Greets
sgrudu
 

BenKropp

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solder qfp

Hi,

I use a hot air fan with a small jet. ( with temperature/flow adjustment capabilities)
- Use flux to coat all of the ic's pads on the pcb.
- Put some solder on the tip of the soldering iron and drag it regularily across the ic pins.
- Use flux again to coat all of the ic's pads on the pcb.
- Place the IC on the board on top of the solder and fix it at 2 corners
- Use the hot air fan and heat the pins while pressing down the device weakly

That's it. Works well even with 0.4mm fine pitch.
 

Fragrance

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how to solder tqfp package

Hi Friend


Please try this link there is very good guide for soldring by antex soldring system lot of good tips for best soldring and wise versa

http://www.epemag.wimborne.co.uk

regards
fragrance :lol: :lol: :lol:
 

johnyaya

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tqfp hand solder

Jayson - What you remove the flux with depends on the type of flux. Most rosin and no-cleans can be cleaned with isopropyl alcohol.

NikZetaJones - The technique you use depends on the equipment available. Magnification will definately help you inspect your work. When using a plain soldering iron I apply ample solder to each pin and then remove excess with solder wick. The most important part of the pin when soldering is the back-side, the side you cannot easily see. When I use a hot-air soldering system and solder paste on prototypes (no stencil yet), I apply paste in a line across the pads, then isolate each pad by pushing a fine-tip scribe lightly between pads. This removes just enough paste from between the pads to eliminate cross-flow between pads during reflow.
 

Beepster

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hand soldering tqfp

To remove rosin flux.
The sooner it is removed the better. After a day it is much harder to remove. Best to di within 10 minuets.

I use XYLOL (XYLENE) from a paint store.
While you are touching ground of the board with one hand, use a 1cm wide soft brush to apply XYLOL and move it around for ~30 seconds.

Holding ground, and the board at 45 degrees over a glass tray,
Use something like a big eye-dropper to flow fresh clean XYLOL over the area. Remove excess with a towel.
Still holding the boards ground, blow off with compressed air if you have it. Static will not harm your ic's.

Do not let XYLOL sit on the board for more than 2-3 minuets, it will harm the solder mask.

Again, good luck !
The beepster,
 

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