STM32F103CB, which is TQFP 48-pin
For the first experimental version of FST-01, I use STM32F103CB, 48-pin TQFP chip.
PCB Design constraint
For FST-01 size (26mm x 13mm, approximately), I needed to have smaller pad pattern of 48-pin TQFP than recommended footprint.
This is not good. For hand soldering, pad pattern is better to be longer.
Articles for hand soldering (in Japanese)
I read following two articles.
- ＱＦＰのハンダ付けは手作業でできる0.5mmピッチのＱＦＰをピッチ変換基板に手作業でハンダ付けする方法: http://verilogician.net/elecDIY/QFPsold/TQFPsold.html
- 0.5mm ピッチ QFP のハンダ付け: http://www002.upp.so-net.ne.jp/uratan/ArmUZK/solder.html
- Positioning of IC is most important. It would be good to use good glue.
- Loupe is needed (for me). I use head loupe of 2x.
- Touch the head of soldering iron to pad pattern of PCB, not to lead of IC.
- Solder wick is our friend.
- We don't need solder paste, but it would be good to use it.
- QFN soldering is easier for me.