As part of a project work of my studies I have designed a board with which I want to read a KNX bus. Unfortunately, two identical prototypes broke down and I'm not sure why (the components were soldered cleanly and the PCB also made a very good impression, so I don't think it was because of that). When connecting the KNX bus, the miniature KNX transceiver became very hot after a short time, but visually there is no damage, unfortunately my laptop does not recognize the board or the microchip (MCP2221) that sits next to it now. I will probably replace both parts but would like to find out what the problem is.
(I have connected the KNX transceiver according to example circuit 3 (FIgure 3. Page 4) from the data sheet (DS12399) where the buck converter is deactivated. Additionally I switched off the linear regulator by short circuiting VCCCORE and VDD_REGIN (datasheet page 16 and 17). At this point I suspect my error. I hope you can recognize an error with the help of my circuit diagram and can help me further.
