From analog to RF design [review]

RF circuits are differentiated from conventional analog circuits in the sense that they require more attention to high frequency performance and distortion. Analog design has hitherto been carried out with emphasis on operational amplifiers. Their main design constraints are stability and noise. Important applications are sigma-delta converters. Other ADCs and DACs however suffer firstly from mismatch. Communications circuits, such as synthesizers and PLLs require stable feedback loops with low-noise devices. They also involve VCOs and LNAs which require high-frequency devices and better models for distortion. This is different indeed from conventional analog design.