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United States Patent 6,107,893
Forbes Aug. 22, 2000

Voltage tunable active inductorless oscillator


An inductorless voltage controlled oscillator that may be fabricated using CMOS circuit elements. In one aspect, the present invention includes a synthetic inductance formed on a substrate and having first and second power supply terminals and a signal port. Additionally, an active admittance transformation network is formed on the substrate and coupled to the synthetic inductance and to the port. The synthetic inductance manifests an admittance at the port which has an inductive component and a positive real component. The active admittance transformation network transforms the positive real component of the synthetic inductance admittance to a negative real component and preserves the inductive character of the synthetic inductance admittance. The synthetic inductance can provide an effective Q of greater than twenty. The active admittance transformation network and the synthetic inductance cooperate to produce a voltage-variable oscillation frequency in excess of fifty megahertz. Voltage dependent values for parasitic impedances and admittances of the first and second amplifiers cause an oscillation frequency .omega.(OSC) to be swept over a range of tens or hundreds of megahertz by altering a supply voltage. Significantly, the voltage controlled oscillator may be formed as a monolithic CMOS or a BiCMOS integrated circuit. As a result, the voltage controlled oscillator may be cost-effectively combined with other kinds of circuits, such as signal processors and digital circuits.

Inventors: Forbes; Leonard (Corvallis, OR).
Assignee: Micron Technology, Inc. (Boise, ID).
Appl. No.: 204,457
Filed: Dec. 2, 1998
Intl. Cl. : H03B 5/00, H03B 7/00, H03H 11/00
Current U.S. Cl.: 331/132; 331/115; 331/181; 333/215
Field of Search: 331/36 L, 108 R, 108 L, 115, 117 R, 117 FE, 117 D, 132-134, 181, 177 R; 333/213-217

References Cited | [Referenced By]

U.S. Patent Documents
3,824,496Jul., 1974Hekimian 331/132
4,760,353Jul., 1988Perkins 331/132
5,175,513Dec., 1992Hara 331/115
5,343,170Aug., 1994Lee 331/132
5,726,613Mar., 1998Hayashi et al. 333/214

Other References

Edited by Razavi, Behzad B., AT&T Laboratories, "Monolithic Phase-Locked Loops and Clock Recovery Circuits," IEEE Press, 1996, p. "Reference P2"; Abstract for IEEE Product No. PC5620-QAJ.

Hara, S., and Tokumitsu, T., "Monolithic microwave active inductors and their applications," IEEE International Symposium on Circuits and Systems, Singapore, Jun. 11-14, 1991, Abstract No. B9210-1350H-019, (Catalog No. 91CH3006-4), p. 5, vol. xlviii+3177, pp. 1857-1860, vol. 3.

Ali M. Niknejad and Robert G. Meyer, "Analysis, Design, and Optimization of Spiral Inductors and Transformers for Si RF IC's," IEEE Journal of Solid-State Circuits 33(10):1470-1481, Oct. 1998.

Lawrence M. Burns, "Applications for GaAs and Silicon Integrated Circuits in Next Generation Wireless Communication Systems," IEEE Journal of Solid-State Circuits 30(10):1088-1095, Oct. 1995.

Jurgen Hartung, "Integrated Passive Components in MCM-Si Technology and their Applications in RF-Systems," 1998 International Conference on Multichip Modules and High Density Packaging, pp. 256-261.

Hitoshi Hayashi and Masahiro Muraguchi, "A Novel Broad-Band MMIC VCO Using an Active Inductor," IEICE Trans. Fundamentals E81-A(2):224-229, Feb. 1998.

Donald A. Hitko et al., "A 1V 5mW, 1.8GHz, Balanced Voltage-Controlled Oscillator with an Integrated Resonator,"Proceedings 1997 International Symposium on Low Power Electronics and Design, ACM, New York, NY, Aug. 18-20, 1997, pp. 46-51.

Jan Craninckx and Michiel Steyaert, "A 1.8-GHz Low-Phase-Noise Spiral-LC CMOS VCO, " 1996 Symposium on VLSI Circuits Digest of Technical Papers, pp. 30-31.

Behzad Razavi, "A Study of Phase Noise in CMOS Oscillators, " IEEE Journal of Solid-State Circuits 31(3):331-343, Mar. 1996.

Primary Examiner: Mis; David
Attorney, Agent or Firm: Dorsey & Whitney LLP
31 Claims, 5 Drawing Figures

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