The STMicroelectronics ST25DV04K devices are NFC RFID tags offering respectively 4 Kbit, 16 Kbit, and 64 Kbit of electrically erasable programmable memory (EEPROM). ST25DV04K offer two interfaces. The first one is an I2C serial link and can be operated from a DC power supply. The second one is a RF link activated when ST25DV04K act as a contactless memory powered by the received carrier electromagnetic wave. In I2C mode, the ST25DV04K user memory contains up to 512 bytes, 2048 bytes and 8192 bytes, which could be split in 4 flexible and protectable areas.

Two-wire I2C serial interface supports 1MHz protocol
Single supply voltage: 1.8V to 5.5V
Multiple byte write programming (up to 256 bytes)
Contactless interface
Based on ISO/IEC 15693
NFC Forum Type 5 tag certified by the NFC Forum
Supports all ISO/IEC 15693 modulations, coding, sub-carrier modes and data rates