A System-on-Chip EPC Gen-2 Passive UHF RFID Tag With Embedded Temperature Sensor

This paper presents a system-on-chip passive RFID tag with an embedded temperature sensor for the EPC Gen-2 protocol in the 900-MHz UHF frequency band. A dual-path clock generator is proposed to support both applications with either very accurate link frequency or very low power consumption. On-chip temperature sensing is accomplished with a time-readout scheme to reduce the power consumption. Moreover, a gain-compensation technique is proposed to reduce the temperature sensing error due to process variations by using the same bandgap reference of the tag to generate bias currents for both the current-to-digital converter and the clock generator of the sensor. Also integrated is a 128-bit one-time-programmable (OTP) memory array based on gate-oxide antifuse without extra mask steps. Fabricated in a standard 0.18- μm CMOS process with analog options, the 1.1-mm2 tag chip is bonded onto an antenna using flip-chip technology to realize a complete tag inlay, which is successfully demonstrated and evaluated in real-time wireless communications with commercial RFID readers. The tag inlay achieves a sensitivity of -6 dBm and a sensing inaccuracy of ±0.8° C (3 σ inaccuracy) over operating temperature range from -20°C to 30°C with one-point calibration.

[1]  M. Chan,et al.  Universal high voltage multiplexer for CMOS OTP memory applications , 2008, 2008 IEEE International Conference on Electron Devices and Solid-State Circuits.

[2]  Amine Bermak,et al.  A Sub-$\mu$ W Embedded CMOS Temperature Sensor for RFID Food Monitoring Application , 2010, IEEE Journal of Solid-State Circuits.

[3]  Hoi-Jun Yoo,et al.  A 5.1-/spl mu/W UHF RFID tag chip integrated with sensors for wireless environmental monitoring , 2005, Proceedings of the 31st European Solid-State Circuits Conference, 2005. ESSCIRC 2005..

[4]  J.G. Maneatis,et al.  Low-jitter and process independent DLL and PLL based on self biased techniques , 1996, 1996 IEEE International Solid-State Circuits Conference. Digest of TEchnical Papers, ISSCC.

[5]  Fan Zhang,et al.  A 9.2µA gen 2 compatible UHF RFID sensing tag with −12dBm Sensitivity and 1.25µVrms input-referred noise floor , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[6]  Kwyro Lee,et al.  Three-transistor one-time programmable (OTP) ROM cell array using standard CMOS gate oxide antifuse , 2003, IEEE Electron Device Letters.

[7]  Steve Lazar,et al.  A Passive UHF RFID Transponder for EPC Gen 2 with -14dBm Sensitivity in 0.13μm CMOS , 2007, 2007 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[8]  H.C. Luong,et al.  A 7-μW clock generator in 0.18-μm CMOS for passive UHF RFID EPC G2 tags , 2007, ESSCIRC 2007 - 33rd European Solid-State Circuits Conference.

[9]  Mansun Chan,et al.  OTP Memory for Low Cost Passive RFID Tags , 2007, 2007 IEEE Conference on Electron Devices and Solid-State Circuits.

[10]  Chi-Ying Tsui,et al.  Analysis and Design Strategy of UHF Micro-Power CMOS Rectifiers for Micro-Sensor and RFID Applications , 2007, IEEE Transactions on Circuits and Systems I: Regular Papers.

[11]  David Blaauw,et al.  An ultra low power 1V, 220nW temperature sensor for passive wireless applications , 2008, 2008 IEEE Custom Integrated Circuits Conference.

[12]  Apinunt Thanachayanont,et al.  Self-powered wireless temperature sensors exploit RFID technology , 2006, IEEE Pervasive Computing.

[13]  A.A. Abidi,et al.  Multi-Phase Injection Widens Lock Range of Ring-Oscillator-Based Frequency Dividers , 2008, IEEE Journal of Solid-State Circuits.

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

[15]  Kofi A. A. Makinwa,et al.  A CMOS temperature sensor with an energy-efficient zoom ADC and an Inaccuracy of ±0.25°C (3s) from −40°C to 125°C , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[16]  Akinori Matsumoto,et al.  An on-chip CMOS relaxation oscillator with power averaging feedback using a reference proportional to supply voltage , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[17]  M. Horowitz,et al.  Precise delay generation using coupled oscillators , 1993, 1993 IEEE International Solid-State Circuits Conference Digest of Technical Papers.

[18]  Juha Kostamovaara,et al.  A 1-V, self adjusting, 5-MHz CMOS RC-oscillator , 2002, 2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353).

[19]  Jin Liu,et al.  A 0.8V 1.52MHz MSVC Relaxation Oscillator with Inverted Mirror Feedback Reference for UHF RFID , 2006, IEEE Custom Integrated Circuits Conference 2006.

[20]  Kofi A. A. Makinwa,et al.  A 1.2V 10µW NPN-based temperature sensor in 65nm CMOS with an inaccuracy of ±0.2°C (3s) from −70°C to 125°C , 2010, 2010 IEEE International Solid-State Circuits Conference - (ISSCC).

[21]  Eric A. M. Klumperink,et al.  Low-Frequency Noise Phenomena in Switched MOSFETs , 2007, IEEE Journal of Solid-State Circuits.

[22]  F. Ayazi,et al.  Process and temperature compensation in a 7-MHz CMOS clock oscillator , 2006, IEEE Journal of Solid-State Circuits.