Hi everyone,

Is there a significant advantage of using QFN over QFP or QFP over QFN?

Does that have to do with the chip area or parasitic effects between the pins?

Thank you!

 

If you drop them on the floor, you can still use the QFN whereas you might have to straighten out the pins of the QFP.
I've used both, and sometimes the QFNs have soldered as easy as anything, and sometimes they have been a real pain.
The QFPs are more consistent, but you will have to spend some time removing solder bridges.
But if someone with a fancy machine assembles and solders them for you, then does it matter?
I expect that the capacitance between the tracks connecting to it will dominate over the capacitance between the pins.
Do the QFNs take up slightly less room for the same device?

 

The advantages of QFN:

• Less PCB space: a QFP48 needs 81 mm^2 PCB space, a QFN48 only 49 mm^2. This is 65% more space for the QFP
• QFN housings are usually a few cents cheaper than QFP
• Better thermal characteristics of the QFN. It has usually an additional "pin" called thermal pad, which is directly connected to the die substrate. Together with a soldering pad and some vias the heat produced by the chip can be spreaded by a large ground plane in the inner layers of the PCB
• QFNs have lower parasitic inductance at their pins. That improves signal integrity for fast switching digital signals

The disadvantage of QFN

• Soldering is much more difficult for a hobbyist. But in professional electronics production this does'nt matter because there are used pick and place machines and reflow soldering machines. Fore theye machines there is no difference whethef they are soldering a QFN or QFP.

 

I've seen QFPs with the thermal pad as well.

 

I've seen QFPs with the thermal pad as well.

Yes, that is true. But QFPs with thermal pad are really rare and only for special applications while there is almost no QFN without a thermal pad.