The ST25DV04KC, ST25DV16KC and ST25DV64KC devices (hereinafter referred collectively to as ST25DVxxKC) are NFC RFID tags offering respectively 4, 16, and 64‑Kbit of electrically erasable programmable memory (EEPROM). These devices feature two interfaces: the first one is an I²C serial link that can be operated from a DC power supply, the second one is an RF link activated when the device acts as a contactless memory powered by the received carrier electromagnetic wave.In I²C mode, the user memory contains up to 512, 2048, or 8192 bytes, which can be split in four flexible and protectable areas.In RF mode, following ISO/IEC 15693 or NFC Forum Type 5 recommendations, the user memory contains up to 128, 512, or 2048 blocks of 4 bytes, which can be split in four flexible and protectable areas.The ST25DVxxKC devices offer a fast transfer mode between the RF and contact worlds, thanks to a 256 bytes volatile buffer (also called mailbox). In addition, the GPO pin provides data about incoming events, like the RF field detection, RF activity in progress, or mailbox message availability. An energy harvesting feature is also available, when external conditions make it possible.