CMOS RF Design for Reliability Using Adaptive Gate–Source Biasing

An adaptive gate-source biasing scheme to improve the MOSFET RF circuit reliability is presented. The adaptive method automatically adjusts the gate-source voltage to compensate the reduction in the drain current subjected to various device reliability mechanisms. The MOS DC circuit using the adaptive technique is less sensitive to a threshold voltage and mobility degradations from a long-term stress effect. A class-AB RF power amplifier example shows that the use of a source resistance makes the power-added efficiency robust against the threshold voltage and mobility variations, whereas the use of a source inductance is more reliable for the input third-order intercept point.