Hi, HerrPhy,
Pls download the data sheet of LPC11U2x from the link:
https://www.nxp.com/docs/en/data-sheet/LPC11U2X.pdf
Pls refer to the Fig 4, all the LPC11U22FBD48/301, LPC11U23FBD48/301,LPC11U24FBD48/301, LPC11U24FBD48/401 are pin to pin compatible, but only the memory size are different.
xiangjun_rong_0-1598943823840.png
BTW, this is the resource of the chip
xiangjun_rong_1-1598943928892.png
Hope it can help you
BR
XiangJun Rong