A Passive UHF RF Identification CMOS Tag IC Using Ferroelectric RAM in 0.35-/22m Technology Hiroyuki Nakamoto, Daisuke Yamazaki, Takuji Yamamoto, Hajime Kurata, Satoshi Yamada, Kenji Mukaida

Abstract

A passive UHF RF identification (RFID) tag IC with embedded 2-KB ferroelectric RAM (FeRAM) for rewritable appli- cations enables a 2.9 times faster read-and-write transaction time over EEPROM-based tag ICs. The resulting FeRAM-based tag has a nominally identical communication range for both read and write operations, which is indispensable for data write applications. The evaluated tag communication range with a folded dipole antenna is from 0 m to 4.3 m, at the 953-MHz carrier frequency with 4-W transmitting Effective Isotropic Radiated Power (EIRP) from a reader/writer. The developed tag IC features two circuit blocks to maximize the communication range in 0.35- m CMOS/FeRAM technology. First is a CMOS-only full-wave rectifier, which can improve the measured efficiency by up to 36.6% by reducing the input parasitic capacitances and optimization of multiplier struc- ture. This efficiency is more than twice that of previously-published results. Second is a low-voltage current-mode ASK demodulator to accommodate a low-breakdown voltage of FeRAM, which con- verts the ASK power modulation into a linearly modulated current over an incoming power range of 27 dB, corresponding to the en- tire communication range. The developed demodulator can thus resolve the primary design tradeoff issue between device protec- tion and detection sensitivity in the conventional voltage-mode de- modulator.