Transceivers with Active Inductors & Transformers
This chapter explores the use of CMOS active inductors in transceivers for wireless and wire-line data communications. The chapter starts with an investigation of the use of CMOS active inductors in design of low-noise amplifiers (LNAs) in Section 5.1. We show that due to stringent noise requirements, active inductors are only used at the output node of LNAs where a large capacitance is typically encountered to boost the gain the LNAs. Inductors used for narrowband impedance matching remains to be spiral inductors. For LNAs in ultra wideband applications, the use of active inductors provides the key advantages of boosting the voltage gain of the amplifiers over a large frequency range. Section 5.2 investigates the use of CMOS active inductors in design of limiting amplifiers encountered in optical front-ends. We show that CMOS active inductors are used extensively in these amplifiers for bandwidth improvement. In Section 5.3, our attention is turned to the design of RF phase shifters where spiral inductors and MMIC passive components are replaced with CMOS active inductors to reduce silicon consumption, improve phase tuning range, and lower insertion loss. Section 5.4 examines the use of CMOS active inductors in wire-line transceivers. Class A and class AB current-mode transmitters, pre-emphasis and post-equalization networks are investigated. Section 5.5 investigates the use ofCMOSactive inductors in QPSKmodulators for Blue-tooth applications. The chapter is concluded in Section 5.6.
KeywordsPhase Noise Active Inductor Spiral Inductor Quadrature Oscillator Silicon Consumption
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