A Compact Low-Noise Weighted Distributed Amplifier in CMOS

Y.J. Wang and A. Hajimiri

The noise figure (NF) of a front-end low-noise amplifier (LNA) places a lower bound on the sensitivity of a receiver. In a conventional LNA, there is a tradeoff between the intrinsic input capacitance of the input transistors and the achievable bandwidth (BW) of the amplifier. This makes it necessary to use smaller transistors at higher gate overdrive voltages to simultaneously achieve greater BW and better NF. Unfortunately, biasing the transistor in this fashion yields a power-inefficient design. Furthermore, the need for a smaller capacitance presents a challenge to electrostatic discharge (ESD) protection of the input due to its added capacitance.