Hi @shai_b
For LPC1754FBD80, we have two PN, LPC1754FBD80,551 and LPC1754FBD80K
https://www.nxp.com/part/LPC1754FBD80#/
I guess your "LPC1754FBD80" means "LPC1754FBD80,551"?
If so, the only difference between LPC1754FBD80,551 and LPC1754FBD80K is packaging. see below:

The chip itself is the same. No difference. LPC1754FBD80K is new packaging.
Hope this helps,
Jun Zhang