something odd with the footprint of TDA21535
I'm not sure what the issue is, but the datasheet for this part has "28" pins listed.. and has a diagram of a QFN like this;
in the printed board there's isnt a pin in the "6" position, so the symbol only has "27" pins listed.
the infineon datasheet has two sets of drawings; some showing this pin is to be foreseen, and some showing it is not to be foreseen; reading between the lines- it's could be a question of cross-compatibility. if there is indeed a pin in the location "6" then it would need a pad to be added on the PCB, so that the component doesn't sit proud on the mask when it's being soldered.
- is there actually a physical pin in the location "28" or "6" (depending on how you see it)?
the way the infineon datasheet is worded makes me think that this additional pin adds flexibility to use other standard components; if that's indeed the case we should consider adding the missing pin to facilitate swapping this part to another one without changing the PCB.
Having said that the infineon datasheet is not particularly easy to digest, so I could be completely wrong.