This paper presents a passive UHF radio frequency identification (RFID) transponder with 2 k bit standard commercial EEPROM in compliance with the NCITS 256 protocol. The communication range is 1.5 m for the read operation and 0.3 m for the write operation with 4 W effective isotropic radiated power (EIRP) at 915 MHz. The integrated IC is implemented in SMIC 0.18 μm EEPROM CMOS technology. The die size is 1 mm × 1 mm. The energy of the tag is harvested from RF electromagnetic waves transmitted by the reader with the help of a Schottky diode rectifier and achieves 25% power efficiency.