An Ultra-Low-Power Long Range Battery/Passive RFID Tag for UHF and Microwave Bands With a Current Consumption of 700 nA at 1.5 V

We present for the first time, a fully integrated battery powered RFID integrated circuit (IC) for operation at ultrahigh frequency (UHF) and microwave bands. The battery powered RFID IC can also work as a passive RFID tag without a battery or when the battery has died (i.e., voltage has dropped below 1.3 V); this novel dual passive and battery operation allays one of the major drawbacks of currently available active tags, namely that the tag cannot be used once the battery has died. When powered by a battery, the current consumption is 700 nA at 1.5 V (400 nA if internal signals are not brought out on test pads). This ultra-low-power consumption permits the use of a very small capacity battery of 100 mA-hr for lifetimes exceeding ten years; as a result a battery tag that is very close to a passive tag both in form factor and cost is made possible. The chip is built on a 1-mum digital CMOS process with dual poly layers, EEPROM and Schottky diodes. The RF threshold power at 2.45 GHz is -19 dBm which is the lowest ever reported threshold power for RFID tags and has a range exceeding 3.5 m under FCC unlicensed operation at the 2.4-GHz microwave band. The low threshold is achieved with architectural choices and low-power circuit design techniques. At 915 MHz, based on the experimentally measured tag impedance (92-j837) and the threshold spec of the tag (200 mV), the theoretical minimum range is 24 m. The tag initially is in a "low-power" mode to conserve power and when issued the appropriate command, it operates in "full-power" mode. The chip has on-chip voltage regulators, clock and data recovery circuits, EEPROM and a digital state machine that implements the ISO 18000-4 B protocol in the "full-power" mode. We provide detailed explanation of the clock recovery circuits and the implementation of the binary sort algorithm, which includes a pseudorandom number generator. Other than the antenna board and a battery, no external components are used.

[1]  C.A.T. Salama,et al.  A CMOS bandgap voltage reference , 1979, IEEE Journal of Solid-State Circuits.

[2]  Sau-Mou Wu,et al.  A transponder IC for wireless identification systems , 1996, Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications.

[3]  Y. Sugawara,et al.  A 13.56 MHz CMOS RF identification transponder integrated circuit with a dedicated CPU , 1999, 1999 IEEE International Solid-State Circuits Conference. Digest of Technical Papers. ISSCC. First Edition (Cat. No.99CH36278).

[4]  Martin Fischer,et al.  Fully integrated passive UHF RFID transponder IC with 16.7-μW minimum RF input power , 2003, IEEE J. Solid State Circuits.

[5]  G. De Vita,et al.  Design criteria for the RF section of long range passive RFID systems , 2004, Proceedings Norchip Conference, 2004..

[6]  Ron Oliver,et al.  Design of ultra-low-cost UHF RFID tags for supply chain applications , 2004, IEEE Communications Magazine.

[7]  Wooi Gan Yeoh,et al.  A CMOS 2.45-GHz radio frequency identification tag IC with read/write memory , 2005, 2005 IEEE Radio Frequency integrated Circuits (RFIC) Symposium - Digest of Papers.

[8]  F. Koçer,et al.  A long-range RFID IC with on-chip ADC in 0.25 /spl mu/m CMOS , 2005, 2005 IEEE Radio Frequency integrated Circuits (RFIC) Symposium - Digest of Papers.

[9]  C. Dehollain,et al.  Remotely powered addressable UHF RFID integrated system , 2005, IEEE Journal of Solid-State Circuits.

[10]  H. Yoshida,et al.  A 950-MHz rectifier circuit for sensor network tags with 10-m distance , 2006, IEEE Journal of Solid-State Circuits.

[11]  Damith Chinthana Ranasinghe,et al.  Analysis of UHF RFID CMOS rectifier structures and input impedance characteristics , 2005, SPIE Micro + Nano Materials, Devices, and Applications.

[12]  D. Yamazaki,et al.  A Passive UHF RF Identification CMOS Tag IC Using Ferroelectric RAM in 0.35-$\mu{\hbox {m}}$ Technology , 2007, IEEE Journal of Solid-State Circuits.