Architecture considerations and integrated-passives-based design for a dual-mode GPRS-WLAN SiGe RF transceiver

Seamlessly roaming user applications in converging GSM-WLAN environments are creating the need for highly integrated, dual-mode transceivers, amenable to single-die integration on silicon. Based on the direct conversion principle, an efficient system architecture that can be switched between both standards is proposed. It is shown that, for implementing the dual-mode radio, the design of wideband RF cells and switches is called for, which is nontrivial. Appropriate design techniques based on the extensive usage of on-chip passives are proposed to address the design of the dual-mode RF circuitry and render their performance on silicon as predictable as possible. The development of a SiGe BiCMOS GPRS-WLAN transceiver is showcased. Measurement results are provided at the cell level, for a 1.8-2.5 GHz 24 dB-gain LNA and an embedded +24 dBm WLAN PA.