Rafael Ignacio Zurita wrote: > Is it needed all the VSS > soldered before this kind of test?
It certainly can't hurt. I don't know how they connect internally, but at least all the VSS on the left side (pins 2, 11, 12) should be connected to ground. (And connecting pin 23 won't be much of an effort either :) > Should I put capacitors first before test? It can't hurt either. Didn't you have that problem a while ago already ? I.e., that you didn't have capacitors and the chip performed erratically. Also, is your MCU actually powered ? There doesn't seem to be a direct connection between VOUT33 and VDD*, so I don't know if you're even in a defined state. Regarding soldering, the solder will flow towards hot surfaces. So you don't need to heat up a single pin at a time but you can heat up several pins at once. Plus, make sure you also heat the pad under the pin. Only then will you get a proper solder joint. I usually solder QFNs and such in two passes: the first pass is to just establish enough solder joints, no matter how untidy, that the chip stays in place. The second pass is to reflow the areas where things didn't work out. In the second pass, I can add or remove solder. Also make sure your iron is hot enough. If it's just at the point where solder will melt, it will get too cold as soon as you touch something. A range of about 280 C to 300 C should be good, but you'll have to find what works best with your iron and your station. Unless you've cranked up the heat far too high, you also don't have to be in a rush to remove the iron from a solder joint. You have to keep it there long enough to fully melt the solder and to fully heat pin and pad. Only then will you get a good solder joint. Another thing to check is that VOUT33 doesn't accidently make contact with VREGIN. Also, the regulator may need a minimum external load of a few uA before it actually can regulate. - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
