temperature profile for the reflow soldering of the ADUCM350

I have made two revisions of my board so far.  Each time, I had 4 copies of the board fabricated, and two stuffed, and both boards worked (i.e. downloaded code and ran it straight away... is that what you meant by your board doesn't "work well"?).  I had each pair of boards stuffed by an assembly house, but I'm pretty sure the assembly house placed all the components by hand, since I only ordered two boards to be stuffed.  My guess is the trick is in the board manufacturing. Not many board fabrication houses can hold the tolerances on the soldermask alignment to ensure that there will be soldermask insulation between every pad for the BGA, since the pitch is so small at 0.5 mm.  Can you post a closeup photo of your board's footprint for the BGA?  Here's mine.  Have a look at slide 4 and see if your board has similarly concentric soldermask openings around the pads.

I have made two revisions of my board so far.  Each time, I had 4 copies of the board fabricated, and two stuffed, and both boards worked (i.e. downloaded code and ran it straight away... is that what you meant by your board doesn't "work well"?).  I had each pair of boards stuffed by an assembly house, but I'm pretty sure the assembly house placed all the components by hand, since I only ordered two boards to be stuffed.  My guess is the trick is in the board manufacturing. Not many board fabrication houses can hold the tolerances on the soldermask alignment to ensure that there will be soldermask insulation between every pad for the BGA, since the pitch is so small at 0.5 mm.  Can you post a closeup photo of your board's footprint for the BGA?  Here's mine.  Have a look at slide 4 and see if your board has similarly concentric soldermask openings around the pads.