I have a problem that has me struggling. I’m still developing my own Arduino Uno rev 3 and i’m adding footprints to the components ( for handsolder ). But there are 2 problems : the Atmega16u2-mu® and the resistor networks wich i both can’t solder because they are too small.
My question is are there slightly larger parts of them? like parts i can solder.
( For the atmega the pin layout has to be the same )
QFP is easily solderable with a good solder iron and some flux. (The nominal density IPC footprint should be good enough here. A microscope or at least good magnifying glasses would help a lot.)
QFN might mean you would need a good heat gun (Maybe it is enough to increase the toe fillet. This could allow you to solder it using a solder iron.)
If they have a exposed pad then you might either need a good heat gun or you can make a large through hole pad for it such that you can solder it from the bottom side.
You did not specify anything about the resistor network. There are such networks out there that are basically a few 0603 imperial (or 0805 imperial) resistors right next to each other. Such packages can be soldered with nearly anything.
QFP: quad flat package - is a gull wing component similar to SOIC (but with leads on all 4 sides.) So as we do not see the leads it can not be a QFP
QFN: quad flat no lead: This package has no outside leads. The connection points are on the bottom. Normally arranged on the border of the part (meaning if you look from the side you will see the metal connector) From the picture i would guess it is in fact a QFN. (I would however suggest you go for the QFP if you can. It is much easier to solder.)
RES ARRAY 1K OHM 4 RES 1206 CAY16-102J4LF
That is a huge part. So you would not need to worry about it with regards to handsolderability. You can still make your life easier by increasing the pad towards the outside compared to what industry standards suggest. (Use the R_1206_3216Metric_Pad1.42x1.75mm_Handsolder footprint as a guide)
Changing the 33 pin QFN for another package could change the device ID. This Atmel part has to be programmed in situ.
It might be easier to use the FTDI FT232RL for a one off clone board, this is SOIC and much easier to solder