Enhancement on the robustness of a quad-band power amplifier module for GSM/GPRS handsets

Device ruggedness is the major concern about the adoption of power amplifier module in the mobile phone industry. A resistive network was employed to stabilize the sub-harmonic (f/2) loop oscillation for the large periphery device, especially on the output stage. Not only the spurious emission being minimized, but also the robustness of power amplifier is strengthened as operating under severe mismatch condition (VSWR 10:1). Such power chips were integrated with a logarithmic power detecting controller and functioned as a linearly closed-loop power controlled GSM/GPRS power amplifier module. It had successfully demonstrated a highly mismatch susceptibility for all quad-band operations (GSM850, EGSM900, DCS1800, PCS1900).