A single-chip CMOS UHF RFID Reader transceiver for mobile applications

A UHF RFID Reader Transceiver for China standard (840~925 MHz) as well as meeting the protocols of EPC Class-1 Gen-2 and ISO/IEC 18000-6C is presented. To suppress the large self-jammer from transmitter to receiver, an on-chip self-jammer cancellation (SC) circuits and a fully-integrated DC-offset Cancellation (DCOC) circuits with quickly time-varying cut-off frequency are proposed to kill the self-jammer within 15 mus. Furthermore, a mixer with capacitor cross-coupled (CCC) common-gate input stage and vertical NPN BJT switching stage is proposed to achieve high linearity (-8 dBm P1 dB), good wideband matching and low 1/f noise corner. The transmitter integrated with a CMOS class-AB PA of 22 dBm output power in linear mode with 35% PAE, which is suitable for mobile applications, supports the DSB/SSB/PR-ASK modulation schemes and achieves ACPR1 of -45 dBc and ACPR2 of -60 dBc, which satisfies the stringent spectral mask of China local requirements. A sigma-delta PLL with a single LC VCO is also implemented for 250 kHz channel hopping and good phase noise (-126 dBc/Hz at 1MHz offset). The receiver has a sensitivity of down to -77 dBm in the presence of 20 dBm PA output power. The single-chip is implemented in standard 0.18 mum CMOS process. It occupies 13.5 mm² silicon areas, and consumes 113 mA (without PA) from 1.8 V supply voltage.