This paper presents the design of a voltage controlled oscillator (VCO) with small VCO gain (Kvco) variation. To compensate large Kvco variation, a series varactor bank has been added to the conventional LC-tank with parallel capacitor bank array. Implemented in a 0.13m CMOS RF technology, the proposed VCO can be tuned from 4.6GH to 5.5GHz with the Kvco variation of less than 9.6%. While consu...

The multiple-divide technique, using the multi-ratio frequency divider, has a possibility to improve FoM of VCO. This paper proposes a design optimization of LC-VCO using the multiple-divide technique. In the simulated results using 90-nm CMOS model parameters, the optimum frequency range, achieving better than −187.0 dBc/Hz of FoM, can be extended from 6.5–12.5 GHz to 1.5–12.5 GHz. The propose...

This paper proposes an ultra compact LC-VCO. Due to the speed-up of CMOS digital circuits, jitter of ring oscillators is becoming a critical problem. Even though a LCVCO has a better phase noise, a layout size of on-chip inductor is a problem as a clock generator. Thus, the proposed LC-VCO consists of a very compact stacked-spiral inductor and active components placed beneath the inductor. The ...

A differential LC-VCO that adopts a transformer with asymmetric turns-ratio has been proposed. The asymmetric turns-ratio of the transformer leads to the suppression of the AM to FM conversion which is caused by the 1/f noise of the current source transistor. The analysis of the proposed scheme and the improvement in phase noise compare to conventional CMOS LC-VCOs are described. The transforme...

PURPOSE Being overweight/obese, having hypertension, and being postmenopausal are risk factors for the development of congestive heart failure (CHF). A characteristic of CHF is an abnormal V(E)/VCO(2) slope, which is predictive of mortality in patients with CHF. Although the V(E)/VCO(2) slope is well established in CHF patients, little is known regarding interventions for "at-risk" populations....

A low phase noise, low dissipated power and small sized Ka-band voltage-controlled oscillator (VCO), using dual cross-coupled pair configuration and capacitance-splitting technique is presented. The Ka-band VCO circuit uses 0.15 μm GaAs pHEMT technology. The VCO has low phase noise, of 116.36 dBc/Hz, at a 1 MHz offset and can be tuned from 30.5 to 31.22 GHz. The figure of merit (FOM) is -192.36...

ADi erentially controlled monolithic LC-VCO along with a di erential charge pump are used to implement a di erential PLL for substrate noise immunity. The di erential VCO control is achieved with minimal increase in the power consumption and without sacri cing the tuning range. In a 0.5 m CMOS technology the measured VCO phase noise is -119dBc @1.0MHz and the tuning range is 26% of the 1.25GHz ...

This paper aims to introduce a quadrature VCO (voltage control oscillator) which applies superharmonic coupling. The presented quadrature VCO is suitable to be used, both with 2 × subharmonic mixers, as well as 4× subharmonic mixers. It would be impossible to avoid the presence of harmonics in CMOS VCO circuits. These harmonics are in general, undesirable signals which tend to accompany the des...

Voltage-controlled oscillator (VCO) based ADCs have become a topic of great interest due to the unique and attractive signal-processing properties they offer in the design of oversampling converters. Assuming a ring-oscillator structure, the outputs of a VCO toggle between two discrete levels (VDD and GND) like a CMOS digital gate, enabling simple multibit quantization using Dflip-flops. Since ...

A CMOS LC-tank VCO and phase-shifting network are described for a direct-conversion receiver of IEEE 802.11a. The direct-conversion receiver is configured to have sub-harmonic mixing structure which requires multi-phase local oscillator (LO) signals spaced by 45°. A poly-phase filter with 3and 4-stage RC networks generates multi-phase LO signals whose amplitude imbalance is removed by cascaded ...