Please review the chart below for details on the different memory iButtons® available.

Memory iButton®


Model iButton® Type Capacity Security Other Features Write Cycles Service Life @ 25°C Data Sheet
DS1990A ID Only 64 bit ROM Read Only PDF
DS1990R ID Only 64 bit ROM Read Only Presence Detect PDF
DS1971 EEPROM 256 bits 200,000 @  25°C, 50,000 @  85°C 40 Years PDF
DS1973 EEPROM 4096 bits Overdrive 50,000 @  25°C Not Specified PDF
DS1977 EEPROM 32 KB Password Protected Overdrive 100,000 10 Years PDF
D1992L NVRAM 1024 bits Unlimited 10 Years PDF
DS1996L NVRAM 64K bits Overdrive Unlimited 10 Years PDF