Common-rail powered reliability improving technique for single-supply complementary metal oxide semiconductor amplifiers

This paper presents a low-power technique to improve reliability of complementary metal oxide semiconductor (CMOS) amplifiers using a shared bias network for input gate and substrate of transistors. The circuit [named reliability improving circuit (RIC)] significantly reduces discrepancy in amplifier gain (S₂₁, voltage gain), noise figure (NF/NF_min) and output reflection-loss (ORL) parameters resulting from variation in threshold voltage, feature-width, device speed and supply rail. It performs well on both typical- (1.2 V) and low-voltage (0.7 V) platforms of a 90 nm CMOS technology and is able to maintain its consistency within a wide frequency coverage (10-30 GHz) for three different architectures (cascode, low-voltage cascode and common-source). This allows the RIC incorporated front-end to satisfy a broad range of gain, isolation, linearity and NF requirements. The scheme´s biasing arrangement is powered from amplifier rails which permit the overall circuit to be driven from a single main supply. Analysis and simulation results demonstrate the technique improving consistency of figures of merit considerably against different aspects of process/system variation without significant degradation of radio frequency performance.