CMOS RFIC Design Principles
Including numerous examples that clearly illustrate and support important topics, this book provides a practical resource for comprehensive, expert guidance on designing CMOS RF integrated circuits.
TABLE OF CONTENTS CMOS RFIC Design Principles
Chapter 4: Small-Signal MOS Amplifiers for RF
Amplifying stages are needed throughout an RFIC. At the front end stage of a high-performance CMOS RFIC receiver, an amplifier exhibiting low noise and high gain can be a major player in setting the overall noise figure for the entire system. Amplifiers are needed in various stages not only to provide increases in signal amplitude; these amplifiers can also be configured to provide gain in only narrow bands, thereby providing filtering for the system. Active CMOS circuits can also be used to effectively reduce losses in on-chip inductors as well as providing a control function that provides for agile tuning structures. This chapter covers basic amplifier circuits, with a focus on RFIC issues.
4.1 Basic Amplifying Structure
The design of MOSFET RFIC amplifiers requires the designer to toggle between the dc and RF worlds. In the RF world, the designer needs an amplifier that must meet a number of specifications: gain, frequency response, input and output impedance, noise figure, linearity, and power consumption, to name just a few. In turn, these RF characteristics must be set by the dc bias circuits. Competing design parameters often require compromises and trade-offs in the design of amplifiers. The designer should know how the two worlds interact for successful designs to occur. This section covers the basic MOSFET amplifying structure and discusses this interaction.
4.1.1 Single FET with Generalized Load
The most common nMOSFET amplifying configuration is the common source configuration shown in Figure 4.1 (its counterpart, the common source pMOSFET, is...
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