Maxim > Products > Part Number Search Part Number Search Maxim Product Naming Conventions DS1981U-F3-1125+ DS1981U-F3-114C+ DS1981U-F5-1124+ DS1981U-F5-1126+ DS1981U-F5-1130+ DS1981U-F5-1136+ DS1981U-F5-1139+ DS1981U-F5-1145+ DS1982 1Kb Add-Only iButton® DS1982U UniqueWare™ iButton® DS1985 16Kb Add-Only iButton® DS1985U UniqueWare™ iButton® DS1986 64Kb Add-Only iButton® DS19860-F3-W DS1986U Not recommended for new designs