I'm trying to use the capacitative touch chip CPT112S for a project. It comes in QFN20 3x3 package size but the pad layout is different to what I expected and so doesn't fit the DIP adapters I have. I'm prototyping and so need to be able to hand-solder the chips. I was expecting a package like this with pads along the edges and not in the corners:
But instead I got one like this which doesn't fit my adaptors as the pads are positioned right in the corners:
I can't find any information about different package types of QFN packages nor whether there are any DIP adaptors out there that I could use. From some of the answers below there is no standard set of package types for QFN 20 packages.
I need to know the following two things:
- How can I find out what the specifications are for the package that I have so that I can find the appropriate DIP adapter for it? The product datasheet (found by googling CPT112S-DataSheet.pdf - I don't have sufficient reputation for another link!) doesn't have that information.
- How can I identify and therefore specify the particular package type to a PCB manufacturer when it comes time to get some prototype boards printed up?