A new 5.5GHz LNA with gain control and turn-off control for dual-band WLAN systems

A new 5-6GHz LNA (low-noise amplifier) for dual-band WLAN system is presented. For the special operation requirement of dual-band RF systems, this LNA features high/low gain control and turn-off control functions. The LNA is designed in TSMC 3-metal 0.35/spl mu/m SiGe BiCMOS process with an f/sub T/ of 49GHz. In high gain mode, the LNA features a forward gain S21 of 14.5dB, a reverse gain S12 of -39.5dB and a noise figure of 2.2dB at 5.5GHz. In low gain mode, the S21 is -11dB, S12 is -52dB and the NF is 13.6dB. The whole circuit consumes 5.2mA dc current under 3V power supply.