1. A CMOS VCO with 2GHz tuning range for wideband applications Speaker ： Shih-Yi Huang

2. Outline Introduction Band-Switching LC Tank The Designed LC VCO Simulation Result Conclusion References

3. Introduction Ultra-wideband (UWB) system, WPAN UWB system ： 3.1~5 GHz, 6~10.6 GHz The low-frequency band, the first-generation UWB system.

4. Introduction (cont.) Voltage-controlled oscillators, modern communication systems, LO (local oscillator) Wide frequency range, low phase noise, low harmonic distortions, stable output amplitude and low power consumption. LC VCO design, narrow tuning-range, limited range of the variable capacitance of the varactors

5. Introduction (cont.) Band-switching wide-band CMOS VCO LC tank ： switched capacitors and PMOS varactors Accumulation and inversion region of operation the MOS capacitor exhibit a maximum of oxide capacitance, C ox

6. Band-Switching LC Tank RF VCO with a large enough tuning range to compensate the process-variation and temperature offset, we adopt the switched capacitor topology Figure 1. (a) The schematic of LC tank for the band-switch of VCO, (b) using a switched capacitor topology to achieve wide tuning range

7. The Designed LC VCO Figure 2. Wide-band LC VCO M1~M4 ： equivalent to negative resistors to compensate for the energy loss in the LC tank. M5~M10 ： are used for band switch. M11~M14 ： use to accomplish 50 output impedance.

8. PMOS varactor Figure 3. PMOS varactor (a) cross section, (b) characteristic of the device

9. AMOS varactor & PMOS varactor Figure 4. The capacitance of 3 series AMOS varactors Figure 5. The capacitance of 3 series PMOS varactors

10. Simulation tuning range Figure 6. Simulated tuning range. 2.96 GHZ 5.03GHz

11. Simulation output power Figure 7. Output power versus the control voltage. -1.2 dBm -2.2 dBm

12. Simulation phase noise Figure 8. Phase noise from 2.95GHz to 5.03GHz. -92 dBc/Hz at 1-MHz offset -124 dBc/Hz at 1-MHz offset

13. Chip photo Figure 9. Layout photograph of the VCO.

14. Table 1 Comparison of published CMOS VCOs

15. Conclusions A CMOS VCO with 2GHz tuning range is designed. With 8.5mA current from 1.8V power supply, the VCO achieves 2.95~5.03GHz tuning range. The phase noise -124 dBc/Hz ： 2.95GHz -92 dBc/Hz ： 5.03GHz. Better performance with very wide tuning range. VCO is suitable for the UWB low-frequency band applications.

16. References 1. J. Kucera, “Wideband BiCMOSVCOfor GSM/UMTS direct conversion receivers,” in IEEE ISSCC Dig. Tech. Papers, 2001, pp. 374–375. 2. D. Ham and A. Hajimiri, “Concepts and methods of optimization of integrated LC VCOs,” IEEE J. Solid-State Circuits, July 2001, vol. 36, no. 6, pp. 896–909. 3. N. H. W. Fong, J.-O. Plouchart, N. Zamdmer, D. Liu, L. Wagner, C. Plett, and N. G. Tarr, “Design of wide-band CMOS VCO for multiband wireless LAN applications,” IEEE J. Solid-State Circuits, August 2003, vol. 38, no. 8, pp. 1333– 1342. 4. B. De Muer, N. Itoh, M. Borremans, and M. Steyaert, “A 1.8 GHz highly-tunable low-phase-noise CMOS VCO,” in Proc. of IEEE Custom Integrated Circuits Conf., 2000, pp. 585–588. 5. A. Karl, F. Behbahabni, and A. A. Abidi, “RF-CMOS Oscillators with Switched Tuning,” in Proc. of the IEEE Custom Integrated Circuits Conf., May 1998, pp. 555-558. 6. N. Fong, J. Plouchart, N. Zamdmer, D. Liu, L. Wagner, C. Plett and N. Tarr, "Design of wide-band CMOS VCO for multiband wireless LAN applications," IEEE J. Solid-State Circuits, August 2003, vol. 38, no. 8, pp. 1333-1342. 7. P. A Andreani, and S. Mattisson, “On the use of MOS varactors in RF VCO’s,” IEEE J. Solid-State Circuits, June 2000, vol.35, no. 6, pp. 905-910. 8. A.D. Berny, A.M. Niknejad, and R.G. Meyer, "A 1.8-GHz LC VCO with 1.3-GHz tuning range and digital amplitude calibration," IEEE J. Solid-State Circuits, April 2005, vol 40, no 4, pp. 909 – 917. IEEE J. Solid-State Circuits, 9. Rajarshi Mukhopadhyay and Joy Laskar, "Reconfigurable RFICs in Si-based technologies for a compact intelligent RF frontend," IEEE J. Solid-State Circuits, Jan 2005, vol. 53, no. 1, pp. 81-93. 10.Lin Jia, Jian-Guo Ma and Kiat Seng Yeo, "A Novel Methodology for the Design of LC Tank VCO with Low Phase Noise," in Proc. of IEEE International Symposium on Circuits and Systems, May 2005, pp. 376-379. 11.Ji-Hoon Kim and Hyung Joun Yoo, "A dual/wide band quadrature VCO with programmable LC tank for quad-band direct conversion WCDMA/WLAN receiver," in Proc.of International Conference on Consumer Electronics, Jan 2005, pp. 301-302. 12.Chung-Yu Wu and Chi-Yao Yu, "A 0.8V 5.9GHz Wide Tuning Range CMOS VCO Using Inversion-Mode Bandswitching Varactors," in Proc. of IEEE International Symposium on Circuits and Systems, May 2005, pp.5079-508.

17. Thank you for your listening