Abstract
This paper presents a dual band Digitally-Controlled-Oscillator (DCO) based on Ring-Oscillators (RO) topology with differential input/output at 1.45 GHz is proposed. The circuit has two frequency band which switches by a digital mode bit. Switching between two bands of DCO, will change delay path and power consumption during the run time. A new Source-Coupled-Logic (SCL) based reconfigurable delay element with Schmitt-Trigger (ST) characteristic is used in each stage and 6 bits digital code control their current tails. Power consumption profile with frequency in each band has a steady regime. The proposed designs are fully differential, which is appropriate for low jitter high performance applications. The proposed DCO is simulated by spice with CMOS standard 0.18 µm @ 1.8 v supply. The frequency, power consumption and jitter in lower band are 455.2 MHz to 505.1 MHz, 1.98 mW (at 455 MHz), 6.04 ps (at 505.1 MHz) and for upper band are from 1.39 MHz to 1.45 MHz, 9.7 mW (at 1.39 GHz) and 3.48 ps (at 1.45 MHz), sequentially. In this paper also circuit analysis of proposed DCO, delay calculation and comparison and analytical equation for frequency bands are obtained. Also, Monte Carlo and PVT test shows acceptable frequency tolerance.
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References
Palermo, S. M. (1999). A multi-band phase-locked loop frequency synthesizer. Master of Science, Electrical Engineering, Texas A&M University
Mazzanti, A., Uggetti, P., Battagia, R., & Svelto, F. (2004). Analysis and design of a dual band reconfigurable VCO. In Proceedings of the 2004 11th IEEE International Conference on Electronics, Circuits and Systems, 2004. (ICECS 2004) 2004 (pp. 37–40).
Wenlong, J., Tavakol, A., Effendrik, P., van de Gevel, M., Verwaal, F., & Staszewski, R. B. (2012). Design of ADPLL system for WiMAX applications in 40-nm CMOS. In 2012 19th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 2012 (pp. 73–76).
Souri, M., & Ghaznavi-Ghoushchi, M. B. (2015). A 14.8 ps jitter low-power dual band all digital PLL with reconfigurable DCO and time-interlined multiplexers. Analog Integrated Circuits and Signal Processing, 82, 381–392.
Mandal, M., & Sarkar, B. (2010). Ring oscillators: Characteristics and applications. Indian Journal of Pure and Applied Physics, 48, 136–145.
Docking, S., & Sachdev, M. (2004). An analytical equation for the oscillation frequency of high-frequency ring oscillators. IEEE Journal of Solid-State Circuits, 39, 533–537.
Alioto, M., & Palumbo, G. (2001). Oscillation frequency in CML and ESCL ring oscillators. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 48, 210–214.
Pahlavan, S., & Ghaznavi-Ghoushchi, M. B. (2015) A fully-differential reconfigurable schmitt-trigger with design-time/run-time adjustable delay and hysteresis in CMOS 180 nm. Analog Integrated Circuits and Signal Processing
Betancourt-Zamora, R. J., & Lee T. H. (1998). Low phase noise CMOS ring oscillator VCOs for frequency synthesis. In 2nd International Workshop on Design of Mixed-Mode Integrated Circuits, 1998 (pp. 37–40).
Elrabaa, M. E. (2005). A new static differential CMOS logic with superior low power performance. Analog Integrated Circuits and Signal Processing, 43, 183–190.
Alioto, M., & Palumbo, G. (2006). Model and Design of bipolar and mos current-mode logic: cml, ecl and scl digital circuits. New York: Springer.
Xin, C., Jun, Y., & Long-Xing, S. (2011). A fast locking all-digital phase-locked loop via feed-forward compensation technique. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 19, 857–868.
Majd, N. E., & Lotfizad, M. (2011). An ultra-low-power 15-bit digitally controlled oscillator with high resolution. Journal of Emerging Trends in Engineering and Applied Sciences, 2(2), 323–328.
Acknowledgments
The authors wish to thank the shahed ICAS laboratory team for their helps specially: Eng. Souri, Eng. Ghorbani, Eng. Rahimi, Eng. Gorji, Eng. Rafiee, Eng. Ejtahed, Eng. Farsani and Eng. Poshtkohi. The first author specially wishes to thank her beloved parents for their supports and encouragements.
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Pahlavan, S., Ghaznavi-Ghoushchi, M.B. 1.45 GHz differential dual band ring based digitally-controlled oscillator with a reconfigurable delay element in 0.18 μm CMOS process. Analog Integr Circ Sig Process 89, 461–467 (2016). https://doi.org/10.1007/s10470-016-0814-1
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DOI: https://doi.org/10.1007/s10470-016-0814-1