I've been looking at this part for an hour, and I can't for the life of me figure from the datasheet two relationships. I have relationship A? and relationship B?, which I am struggling with. I don't have the part in hand (it's an obscure Asian IC... of course...).
I'm not a master at building footprints, but I have laid plenty of QFNs and usually a datasheet provides a few more of the center to center relationships.
I feel like Asian ICs are the worst offenders with these kinds of under-detailed documents.
This one is crazy because it is not symmetrical. Is it possible to figure out A? and B?
I feel like there must be some assumptions about how the pads are centered to each other or something else here... I don't know want to use an assumption to layout a board though.
What am I missing in this relationship of distance of the two pads in A? -- ?
You are provided with K, which I take as the edge of the relief pad to the edge of the pad. We know the pad size (.4mm by .120mm).
So how could you determine the distance from the row of 14 pads on the top, to top of the first pad in the 10 pad row (I'm calling that distance A?).