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LC Tanks (lc + tank)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

A dual band CMOS complementary Colpitts voltage controlled oscillator

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2007
Sheng-Lyang Jang
Abstract A new fully integrated, dual-band CMOS voltage controlled oscillator (VCO) is presented. The VCO is composed of two complementary Colpitts VCOs and is implemented in 0.18-,m CMOS technology with 2-V supply voltage. The circuit allows the VCO to operate at two resonant frequencies with a common LC tank. This VCO is configured with 2.4- and 5.2-GHz frequency bands with differential outputs. The dual-band VCO operates at 2.39,2.68 GHz and 4.84,5.58 GHz. The phase noises of the VCO operating at 2.4 and 5.13 GHz are ,121.11 and ,111.76 dBc/Hz at 1-MHz offset, respectively, while the VCO draws 7.45/5.92 mA and 14.9/11.84 mW consumption at high/low frequency band from a 2-V supply. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2634,2637, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22814 [source]

Injection-locked GaInp/GaAs HBT frequency divider with stacked transformers

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2007
Hung-Ju Wei
Abstract The first integrated GaInP/GaAs heterojunction bipolar transistor (HBT) injection-locked frequency divider (ILFD) with the stacked transformers is demonstrated around 10 GHz. The stacked transformers formed by only two metal layers provide the inductive coupling in the cross feedback and separate biasing for base and collector to allow for the larger output swing in the LC tank and obtaining wide locking range. Under the supply voltage of 5 V and core power consumption of 20.5 mW, the locking range is 7.8% of the center operating frequency. The chip size of the entire ILFD including probing pads is 1.0 × 1.0 mm2. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2602,2605, 2007; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.22737 [source]

LC-active VCO for CMOS RF transceivers

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2010
Domenico Zito
Abstract A novel fully integrated CMOS LC tank VCO is presented. The LC tanks are implemented by exploiting the active circuit ,boot-strapped inductor' (BSI), which behaves like a high-quality factor inductor. Particularly, the LC tanks have been implemented by introducing a new version of the CMOS BSI circuit, which provides better versatility and design reliability. In order to verify the effectiveness of such an approach, a case study for 5,6,GHz direct-conversion multi-standard WLAN transceivers is presented. The VCO has been designed in a 0.35µm standard CMOS technology. The new BSI exhibits a high-quality factor (higher than 25 over the all frequency range) and provides a high selectivity without introducing a relevant excess of noise, for a better spectral purity and a lower phase noise (PN) of the VCO. The overall VCO circuit consumes 9,mW. The VCO produces an oscillation in the tuning range from 4.91 to 5.93,GHz (nearly equal to 19%). The circuit exhibits a PN of ,129dBc/Hz at 1,MHz of frequency offset from the central frequency (5.4,GHz) and a FOM equal to 189.5,dBc/Hz at 100,kHz and 194.1,dBc/Hz at 1,MHz of frequency offset, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source]

A low voltage folded cascode LNA for ultra-wideband applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2010
Sunil L. Khemchandani
Abstract A low noise amplifier scheme to achieve low-voltage and wide-bandwidth operation is presented. This circuit is based on folded cascode topology combined with wideband impedance matching and shunt peaking load. One of the drawbacks of the proposed scheme is that it uses more area than the conventional cascode due to the two additional inductors and capacitors to implement the capacitively coupled LC tanks. To reduce the area of the circuit, we have used stacked inductors, a brief study of these kinds of inductors is presented. Two low noise amplifiers have been fabricated using a mature 0.35 ,m BiCMOS technology, one using the cascode conventional approach and the other using the proposed topology. Measurement results show that for the same transistors operating conditions, the low-voltage amplifier performance is similar than the conventional cascode. By virtue of the small area of stacked inductors, the size of both low noise amplifiers is comparable. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2495,2500, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25530 [source]

A 57-GHz CMOS VCO with 185.3% tuning-range enhancement using tunable LC source-degeneration

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
Chuan-Wei Tsou
Abstract A 57-GHz CMOS voltage-controlled oscillator (VCO) using tunable LC source-degeneration for operation frequency and tuning-range enhancement is demonstrated. The tunable LC source-degeneration is made by adding two tunable LC tanks, where varactors are used as the needed capacitors, to the source terminals of the cross-coupled transistor pair of the VCO. Compared with the traditional cross-coupled transistor pair, the proposed one significantly decreases the equivalent parallel capacitance (CEQ). This in turn results in the increase of both the operation frequency and the tuning range of the VCO. The measurement result shows the tunable LC source-degeneration achieved a 185.3% enhancement [from 1.36 GHz (53.36,54.72 GHz) to 3.88 GHz (53.36,57.24 GHz)] in tuning range by tuning the varactors of the proposed cross-coupled transistor pair. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2682,2685, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24706 [source]