A Varactor-Less and Dither-Less LC-Digitally Controlled Oscillator with 9-bit Fine Bank, 0.26 mm2 Area, and 6.7 kHz Frequency Resolution

2014 ◽  
Author(s):  
Z. Xu ◽  
M. Sugawara ◽  
K. Mori ◽  
M. Miyahara ◽  
A. Matsuzawa
Keyword(s):  
Frequency Resolution ◽  
Digitally Controlled ◽  
Digitally Controlled Oscillator

A Review of LC-Based Digitally Controlled Oscillator with High Frequency Resolution

2015 ◽  
Vol 24 (05) ◽  
pp. 1530002 ◽  
Author(s):  
Cheng Huang ◽  
Zixuan Wang ◽  
Chao Chen ◽  
Jianhui Wu
Keyword(s):  
Mobile Phones ◽  
High Frequency ◽  
Rapid Development ◽  
Frequency Resolution ◽  
Tabular Form ◽  
Digitally Controlled ◽  
Digitally Controlled Oscillator ◽  
And Performance ◽  
Cellular Mobile ◽  
Future Work

In 2003, a digitally controlled oscillator (DCO) for cellular mobile phones was first proposed and demonstrated, and after that DCOs are widely used along with the rapid development of wireless communications. DCOs based on LC structure gain an advantage over ring oscillators in phase noise and thereby become research hotspot during the last decade. This paper presents a review of inductance capacitance (LC)-DCOs classified by circuit topologies and performance. For each DCO structure, the principle exposition and performance analysis are given in detail. Moreover, a comparison among all kinds of DCOs mentioned in this paper is presented in tabular form. Finally, we discuss the obstacle to the development of DCOs and the possible tendency for future work in summary.

A 5-mW, 1.2–3.5-GHz Capacitive Degeneration in LC-Digitally-Controlled Oscillator for Nano-Satellite Frequency Synthesizers in 90-nm CMOS

2016 ◽  
Vol 25 (12) ◽  
pp. 1650159 ◽  
Author(s):  
Sehmi Saad ◽  
Mongia Mhiri ◽  
Aymen Ben Hammadi ◽  
Kamel Besbes
Keyword(s):  
Phase Noise ◽  
Figure Of Merit ◽  
Frequency Synthesizers ◽  
Frequency Resolution ◽  
Lc Oscillator ◽  
Digitally Controlled ◽  
Additional Resistance ◽  
Capacitance Characteristics ◽  
Digitally Controlled Oscillator ◽  
Low Phase Noise

This paper proposes an 8-bit LC tuned digitally-controlled oscillator (DCO) that exploits a new tunable active inductor (TAI) with a high [Formula: see text]-factor. This TAI achieves a maximum [Formula: see text]-factor value of 98 over a frequency range of 1770[Formula: see text]MHz. It tunes from 3.55[Formula: see text]nH to 15.2[Formula: see text]nH. The proposed TAI is used in the resonator of a wide tunable low-phase-noise DCO-LC oscillator. The tuning circuitry of the DCO with an additional resistance contributes to better effective capacitance characteristics as compared to the basic topology. Thanks to the capacitive degeneration network formed by a resistance connected in parallel with a capacity, the achieved frequency resolution is between 3[Formula: see text]kHz and 16[Formula: see text]kHz without any dithering. The proposed DCO with capacitive degeneration oscillates at a frequency that can be tuned from 1.22 to 3.52[Formula: see text]GHz with 65% tuning range. It consumes 5.2-mA current from a 1.0-V voltage supply, achieves a phase noise of [Formula: see text]105.8[Formula: see text]dBc/Hz at 1-MHz offset and exhibits a figure of merit (FoM) of [Formula: see text]178[Formula: see text]dBc/Hz. The proposed digitally-controlled oscillator was implemented in TSMC 90-nm CMOS MS/RF technology.

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