Noise and Linearity in Amplifiers

This chapter is devoted to low-noise design techniques. First, the expression of the MOSFET channel noise current is derived with a different (and novel) approach, and the effects of transistor parasitics on noise are investigated. The metrics related to amplifier noise are summarized, and the source-generated tuned LNAs are investigated with their basic properties and noise performances. The basic structures of wideband LNAs are discussed in conjunction with the noise feedback concept, leading to noise cancellation solutions. The sources of nonlinearity in amplifiers, its effects on the harmonic distortion, and the intermodulation distortion in connection with the output signal level are discussed, and the metrics related to the nonlinearity and signal level are summarized.