AKM part numbers with the suffix at the end are internal ordering codes for their packaging (tape and reels, trays, and such) so when searching for them on Digi-Key you will get the base part numbers and the ones with the suffixes will be listed at the bottom as “other names” as the suffix formats are no longer used.
AK4490EQ-L will be AK4490EQ Asahi Kasei Microdevices/AKM
AK5572EN-L will be AK5572EN Asahi Kasei Microdevices/AKM
This is internal information to AKM so there is no published documentation.
