Fully Integrated Switch-LNA Front-End IC Design in CMOS: A Systematic Approach for WLAN

A fully integrated front-end IC is demonstrated for 802.11b/g transceivers with integrated power amplifiers. The SP3T-LNA architecture integrates Bluetooth® functionality with transmit and receive for wireless LAN. The transmit switch achieves a P_1dB greater than 33.0 dBm at 2.5 GHz by employing a cross-biasing approach, transistor stacking and deep n-well process. Power handling techniques used for the switches and the associated performance tradeoffs are discussed. The measured noise figure of the LNA and the receive chain comprising both an LNA and a switch is 1.5 dB and 3.0 dB, respectively. The LNA achieves an IIP3 of 7.0 dBm while consuming 7.0 mA of current. The measured switching times are less than 350 ns. The front-end IC employs a 3.3 V supply and occupies 0.64 mm² in 0.18 μm bulk CMOS technology.