Oscillators with Active Inductors & Transformers

This chapter deals with the design of ring and LCtank oscillators using active inductors and transformers investigated in Chapters 2 and 3. The fundamentals of oscillators including voltage or current-controlled oscillators are available in numerous texts, such as [17, 68] and will therefore not be repeated here. Instead, our focus will be given to the circuit implementation of voltage / current-controlled oscillators employing active inductors and transformers for performance enhancement and cost reduction.

The chapter is organized as the followings : Section 6.1 briefly examines the operation of ring oscillators and LC oscillators. The phase noise of oscillators is investigated in detail. Ring oscillators with active inductors are investigated in Section 6.2. Ring oscillators studied in this section include source-coupled ring oscillators, cross-coupled ring oscillators, and Park-Kim ring oscillators. Section 6.3 deals with the design of LC oscillators with active inductors. The use of active transformers in LC oscillators is dealt with in Section 6.4. The design of quadrature LC oscillators using active inductors and transformers is studied in Sections 6.5 and 6.6, respectively. The chapter is concluded in Section 6.8.