Voltage Controlled Oscillators

1. Voltage Controlled Oscillators Yousef Shakhsheer 3/29/2011

2. VCOs Two criteria • Generates a periodic output. • Needs self-sustaining oscillation mechanism;

3. Important Metrics • Frequency • Power • Tunability (Range and linearity) • Jitter • Figure of Merit

4. Three Types of Oscillators • LC-Tank • Ring oscillator • Crystal Oscillator

5. Important Issues • Inductors - inductance modeling and modeling of losses. Topology • Varactors - Topology • Process Variation • Temperature

6. [1] A Sub-1–V 4-GHz CMOS VCO and a 12.5-GHz Oscillator for Low-Voltage and High-Frequency Ahmed H. Mostafa, Mourad N. El-Gamal,& Ramez A. Rafla

7. Mostafa et al, “A Sub-1–V 4-GHz CMOS VCO and a 12.5-GHz Oscillator for Low-Voltage and High-Frequency”

8. Topologies 4-,5- GHz Varactor Tuning 10.5-,12.5- GHz Back-gate Tuning Mostafa et al, “A Sub-1–V 4-GHz CMOS VCO and a 12.5-GHz Oscillator for Low-Voltage and High-Frequency”

9. [2] 1-V Ultra-Low-Power CMOS LC VCO for UHF Quadrature Signal Generation Zheng Wang, Huseyin S. Savci, Numan S. Dogan

10. Proposed Topology Wang et al, “1-V Ultra-Low-Power CMOS LC VCO for UHFQuadrature Signal Generation”

11. Wang et al, “1-V Ultra-Low-Power CMOS LC VCO for UHFQuadrature Signal Generation”

12. [3] A Low-Complexity, Low-Phase-Noise, Low-Voltage Phase-Aligned Ring Oscillator in 90 nm Digital CMOS Jonathan Borremans, JulienRyckaert, Claude Desset, Maarten Kuijk, Piet Wambacq, and Jan Craninckx,

13. Ring Oscillators Problem: • Inductors are hard to design • Jitter added over time in ring oscillator Ring Oscillator: • Reset to reduce jitter, noise, power, etc • Very simple circuitry Borremans et al, “A Low-Complexity, Low-Phase-Noise, Low-Voltage Phase-Aligned Ring Oscillator in 90 nm Digital CMOS”

14. Results Borremans et al, “A Low-Complexity, Low-Phase-Noise, Low-Voltage Phase-Aligned Ring Oscillator in 90 nm Digital CMOS”

15. [4] A Low-Power, Process-and-Temperature-Compensated Ring Oscillator With Addition-Based Current Source Xuan Zhang, and Alyssa B. Apsel

16. PVT Variation Change from single transistor to current source for PVT Zhang et al, “A Low-Power, Process-and-Temperature- Compensated Ring Oscillator With Addition-Based Current Source”

17. Zhang et al, “A Low-Power, Process-and-Temperature- Compensated Ring Oscillator With Addition-Based Current Source”

18. Variation Zhang et al, “A Low-Power, Process-and-Temperature- Compensated Ring Oscillator With Addition-Based Current Source”

19. [5] Low-Voltage, Low-Power and Low Phase Noise 2.4 GHz VCO for Medical Wireless Telemetry Ahmed Fakhr, M. Jamal Deen and Hubert deBruin Fakhr et al, “Low-Voltage, Low-Power and Low Phase Noise 2.4 GHz VCO for Medical Wireless Telemetry”

20. Sub - VT Fakhr et al, “Low-Voltage, Low-Power and Low Phase Noise 2.4 GHz VCO for Medical Wireless Telemetry”

21. Sub-VT Fakhr et al, “Low-Voltage, Low-Power and Low Phase Noise 2.4 GHz VCO for Medical Wireless Telemetry”

22. Crystal • 8.0 MHz - 50.0 MHz • 10 - 100 µW • http://www.abracon.com/Resonators/abm3b.pdf

23. Summing it all up

24. Other Good Resources • Razavi’s Book • Perrott’s slides