Adaptive Body Biasing Circuit for Reliability and Variability Compensation of a Low Power RF Amplifier

This paper presents a simple compensation biasing circuit to enhance the reliability and variability of the low-power radio-frequency (RF) amplifier. The compensation function is achieved through a threshold voltage adjustment, which is realized by an adaptive varying body voltage of power amplifier transistors. The proposed circuit effectively preserves the power amplifier performance over a wide level range of output power under threshold voltage shift and electron mobility degradation. At the 0.63 dBm output power level, the sensitivity of the normalized efficiency of the power amplifier with the proposed compensation circuit under 0.16% threshold voltage shift and 0.16% mobility variations decreases as nearly 6.7 times and 2 times compared to the power amplifier without the compensation circuit, respectively. The operational principle of this structure is studied by deriving the analytical equations. The post-layout simulation results in the 180-nm RF complementary metal-oxide-semiconductor process are obtained and verify the proposed circuit effectiveness.