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

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

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

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

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

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 6

7. 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 8 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 9

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

11. 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, Julien Ryckaert, Claude Desset, Maarten Kuijk, Piet Wambacq, and Jan Craninckx, 12

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

14. Results 14 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 15

16. PVT Variation 16 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. 17 Zhang et al, “A Low-Power, Process-and-Temperature- Compensated Ring Oscillator With Addition-Based Current Source”

18. Variation 18 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 19 Fakhr et al, “Low-Voltage, Low-Power and Low Phase Noise 2.4 GHz VCO for Medical Wireless Telemetry”

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

21. Sub-VT 21 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.co m/Resonators/abm3b.p df 22

23. Summing it all up [1][2][3][4][5] Technology.25 um.180 um.090 um.180 um Voltage.85 V1 V.5 V1 V.4 V Max Freq4 GHz1.6 GHz400 MHz1.8 GHz2.4 GHz Phase Noise -84.7 @ 100 KHz -121 @ 1 MHz -119 @ 200 Hz -109.76 @ 10 MHz -123 @ 1 MHz Power4.08 mW105 uW1.8 mW87 uW41 uW 23

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