Voltage Controlled Oscillators Yousef Shakhsheer 3292011 1 VCOs

Voltage Controlled Oscillators Yousef Shakhsheer 3/29/2011 1

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

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

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

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

[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

Mostafa et al, “A Sub-1–V 4 -GHz CMOS VCO and a 12. 5 -GHz Oscillator for Low-Voltage and High-Frequency” 7

Topologies 4 -, 5 - GHz Varactor Tuning Mostafa et al, “A Sub-1–V 4 -GHz CMOS VCO and a 12. 5 -GHz Oscillator for Low-Voltage and High-Frequency” 10. 5 -, 12. 5 - GHz Back-gate Tuning 8

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

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

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

[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

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” 13

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

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

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” 16

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

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

[5] Low-Voltage, Low-Power and Low Phase Noise 2. 4 GHz VCO for Medical Wireless Telemetry Ahmed Fakhr, M. Jamal Deen and Hubert de. Bruin Fakhr et al, “Low-Voltage, Low-Power and Low Phase Noise 2. 4 GHz VCO for Medical Wireless Telemetry” 19

Sub - VT 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

Crystal • 8. 0 MHz - 50. 0 MHz • 10 - 100 µW • http: //www. abracon. co m/Resonators/abm 3 b. p df 22

Summing it all up [1] Technology. 25 um Voltage . 85 V Max Freq 4 GHz [2] [3] [4] . 180 um. 090 um 1 V . 5 V 1. 6 GHz 400 MHz 1. 8 GHz [5]. 180 um. 4 V 2. 4 GHz Phase Noise -84. 7 @ -121 @ 1 -119 @ -109. 76 @ -123 @ 1 100 KHz MHz 200 Hz 10 MHz Power 4. 08 m. W 105 u. W 1. 8 m. W 87 u. W 41 u. W 23

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