on the datasheet for SN74CBTLV3257 it lists two parts on the PACKAGE OPTION ADDENDUM:
| 74CBTLV3257RGYRG4 |
and
| SN74CBTLV3257RGYR |
| 74CBTLV3257RGYRG4 ACTIVE VQFN RGY 16 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 CL257 |
and
| SN74CBTLV3257RGYR ACTIVE VQFN RGY 16 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 CL257 |
i cannot find any differences in the datasheet or comparing the parts in SiliconExpert; my only guess is one has a thermal pad and one dosnt.
