M24SR04 belongs to the ST25 family which includes all STMicroelectronics NFC/RFID tag and reader products. The M24SR04 devices is a dynamic NFC/RFID tag IC with a dual interface. It embeds an EEPROM memory. It can be operated from an I2C interface or by a 13.56 MHz RFID reader or an NFC phone. The I2C interface uses a two-wire serial interface, consisting of a bidirectional data line and a clock line. It behaves as a slave in the I2C protocol. The RF protocol is compatible with ISO/IEC 14443 Type A and NFC Forum Type 4 Tag.2C interface Two-wire I2C serial interface supports 1 MHz protocol Single supply voltage: 2.7 V to 5.5 V for grade Y 2.4 V to 5.5 V for grade G(1) Contactless interface NFC Forum Type 4 Tag ISO/IEC 14443 Type A 106 Kbps data rate Internal tuning capacitance: 25 pF Memory 512-byte (4-kbit) EEPROM Support of NDEF data structure Data retention: 200 years Write cycle endurance: 1 million Write cycles at 25 °C 600k Write cycles at 85 °C