AVR-Chat

Hello Chuck,

I agree with John the m16 TQFP shown in the Atmel specification doesn't have ground pad ... I believe you may have been looking at the MLF version of the m16. But it should not be feared as with the right (and inexpensive) equipment with practice/equipment you can put on or remove MLFs or DFNs or whatever with ease. 0602 are also easy and no problem.

But if you are going to begin to do SMT soldering you have some equipment requirements and some learning required. Neither are expensive or difficult, but you will have to spend around $400+ US to get basic equipment dependent on how far you want to go in making boards. If you only are going to make a few, you will need couple hundred $ for a hot air rework unit, <$100 for a temperature controlled esd safe soldering iron, assorted proper tips, proper solder, proper flux, good tweezers to place the part, a hold down device to secure the part before soldering and a headband magnifier. A small "hoof tip" soldering tip is definitely required. It takes a little practice but will make it easy to put on fine pitch TQFP, SO and the like. The right solder and flux are also necessary for good results.

If you are going to make many like 2 or more at a time, another few hundred $ for a proper fry pan and convection oven in which you can do small batches of boards dependent primarily on the size of the boards. To do many, you will need the artwork and get stencils and solder paste. And the cost rises a little more but still significantly less expensive that hiring the board assembly out. And it is sort of fun to. But you will soon tire of doing one at a time, resistor by resistor and long to do the entire board in one cooking session. A shortfall of the convection oven and fry pan is knowing how to set them properly, sounds easy - isn't. I can give you my reflow data and settings as your starting point but "your mileage may vary". I've had very good results.

I also suggest that "YouTube" will help you learn what is involved. Search "smt fine pitch soldering" or similar and watch the videos on how it is done. Very instructive and will give you a strong background.

I've been brief here as this is a complex and wide subject. Feel free to contact me direct to spare the forum (unless there is great interest in this topic) if you wish more details. Good luck and I know you can do SMT soldering successfully.

Jim


  ----- Original Message ----- 
  From: Chuck Hackett 
  To: AVR-Chat 
  Sent: Saturday, January 23, 2010 6:59 PM
  Subject: [AVR-Chat] Soldering SMT Atmega16


    
  I am going to try a project using the SMT version of the Atmega16. This
  will be my first SMT project.

  I must admit, I'm a bit nervous at the thought of not being able to pull the
  <<< snip >>>


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