9.2 A single-chip HSPA transceiver with fully integrated 3G CMOS power amplifiers

The increasing complexity and cost pressure of advanced radios for mobile communication devices dictates further integration of front-end components into the transceiver (TRX) in order to reduce bill-of-material (BoM), printed-circuit-board (PCB) area and system cost. In [1] a fully-digital polar modulator is presented, which enables a SAW-less 2G/3G transmitter, in particular by solving the transmitter (TX) noise in receive (RX) band issues at various duplex distances (45/80/190/400MHz). Removing the TX SAW filter by adopting innovative transmitter topologies not only reduced the amount of external components, but also paved the way for monolithic power amplifier (PA) integration into the CMOS transceiver IC. This step poses additional challenges in terms of RX-TX cross-talk, self-heating and remodulation (unwanted frequency modulation of local oscillator by modulated output signal, very critical in IQ direct modulators, much less pronounced in polar modulators). The first integration of a PA with external matching network into a TRX SoC product has been presented in [2] for DECT cordless phones using GFSK modulation. PAs are also successfully integrated into a Wi-Fi TRX SoC, delivering linear transmit power up to 22dBm [3]. Following these earlier examples, this work proposes to fully integrate a PA capable of delivering more than 0.5W of linear RF power for the demanding 3G cellular applications.