A Low-Power Dual-Band Triple-Mode WLAN CMOS Transceiver

This paper describes a 0.18-mum CMOS direct-conversion dual-band triple-mode wireless LAN transceiver. The transceiver has a concurrent dual-band low-noise amplifier for low power consumption with a low noise figure, a single widely tunable low-pass filter based on a triode-biased MOSFET transconductor for multi-mode operation with low power consumption, a DC-offset compensation circuit with an adaptive activating feedback loop to achieve a fast response time with low power consumption, and a SigmaDelta-based low-phase-noise fractional-N frequency synthesizer with a switched-resonator voltage controlled oscillator to cover the entire frequency range for the IEEE WLAN standards. The transceiver covers both 2.4-2.5 and 4.9-5.95 GHz and has extremely low power consumption (78 mA in receive mode, 76 mA in transmit mode-both at 2.4/5.2 GHz). A system noise figure of 3.5/4.2 dB, a sensitivity of -93/-94 dBm for a 6-Mb/s OFDM signal, and an error vector magnitude of 3.2/3.4% were obtained at 2.4/5.2 GHz, respectively