An inductorless CMOS quadrature oscillator continuously tuneable from 3.1 to 10.6 GHz

A relaxation oscillator design is described, which has a phase noise rivaling ring oscillators, while also featuring linear frequency tuning. We show that the comparator in a relaxation-oscillator loop can be prevented from contributing to 1/f 2 colored phase noise and degrading control linearity. The resulting oscillator is implemented in a power efficient way with a switched-capacitor circuit. The design results from a thorough analysis of the fundamental phase noise contributions. Simple expressions modeling the theoretical phase noise performance limit are presented, as well as a design strategy to approach this limit. To verify theoretical predictions, a relaxation oscillator is implemented in a baseline 65 nm CMOS process, occupying 200 mm Â 150 mm. Its frequency tuning range is 1-12 MHz, and its phase noise is L(100kHz) = À109dBc/Hz at f osc = 12MHz, while consuming 90 mW. A figure of merit of À161dBc/Hz is achieved, which is only 4 dB from the theoretical limit.

Section: Introductionmentioning

confidence: 99%

Towards minimum achievable phase noise of relaxation oscillators

Geraedts

Tuijl

Klumperink

et al. 2012

“…Finally, we note that the laser itself is an optical delay oscillator formed by a regenerative feedback mechanism between two mirrors; the delay is the round-trip time for the light beam to travel from one mirror to the other and back again [149]; lasers in fact exhibit multimode oscillation behavior characteristics of delay-line oscillators at times [14,149]. Our third oscillator category, relaxation oscillators, comprises multivibrators and ring oscillators [178,179], which have no passive resonators, relying instead on resistive and capacitive elements to set the frequency. Our third oscillator category, relaxation oscillators, comprises multivibrators and ring oscillators [178,179], which have no passive resonators, relying instead on resistive and capacitive elements to set the frequency.…”

Section: Linear or Nonlinear?mentioning

confidence: 99%

“…Finally, we note that the laser itself is an optical delay oscillator formed by a regenerative feedback mechanism between two mirrors; the delay is the round-trip time for the light beam to travel from one mirror to the other and back again [149]; lasers in fact exhibit multimode oscillation behavior characteristics of delay-line oscillators at times [14,149]. The myriad physics subtleties of these varieties of oscillators are beyond the scope of this paper; for the purposes of our analysis, we note three main components of the delay-line oscillator: a distributed delay, a mode selection, and a nonlinear gain mechanism.Our third oscillator category, relaxation oscillators, comprises multivibrators and ring oscillators [178,179], which have no passive resonators, relying instead on resistive and capacitive elements to set the frequency. This lack of resonant elements makes these oscillators physically much smaller than resonant and delay-line counterparts and thus much more suitable to IC processes.…”

mentioning

confidence: 99%

“…Our third oscillator category, relaxation oscillators, comprises multivibrators and ring oscillators [178,179], which have no passive resonators, relying instead on resistive and capacitive elements to set the frequency. This lack of resonant elements makes these oscillators physically much smaller than resonant and delay-line counterparts and thus much more suitable to IC processes.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Survey of integrated‐circuit‐oscillator phase‐noise analysis

Pankratz

Sánchez-Sinencio

2013

This tutorial distills the salient phase-noise analysis concepts and key equations developed over the last 75 years relevant to integrated circuit oscillators. Oscillator phase and amplitude fluctuations have been studied since at least 1938 when Berstein solved the Fokker-Planck equations for the phase/amplitude distributions of a resonant oscillator.The principal contribution of this work is the organized, unified presentation of eclectic phase-noise analysis techniques, facilitating their application to integrated circuit oscillator design. Furthermore, we demonstrate that all these methods boil down to obtaining three things: (1) noise modulation function; (2) noise transfer function; and (3) current-controlled oscillator gain. For each method, this paper provides a short background explanation of the technique, a step-by-step procedure of how to apply the method to hand calculation/computer simulation, and a worked example to demonstrate how to analyze a practical oscillator circuit with that method.This survey article chiefly deals with phase-noise analysis methods, so to restrict its scope, we limit our discussion to the following: (1) analyzing integrated circuit metal-oxide-semiconductor/bipolar junction transistor-based LC, delay, and ring oscillator topologies; (2) considering a few oscillator harmonics in our analysis; (3) analyzing thermal/flicker intrinsic device-noise sources rather than environmental/parametric noise/ wander; (4) providing mainly qualitative amplitude-noise discussions; and (5) omitting measurement methods/phase-noise reduction techniques.We categorize oscillators into one of three varieties, as illustrated in Figure 3: resonant, delay line, or relaxation. First, the resonant oscillator consists of a nonlinear amplifier and a lumped frequencyselective network or resonator, which typically has a band-pass frequency response with a single magnitude peak as indicated conceptually in the figure. This resonator can take the form of an LC tank circuit, dielectric puck, quartz crystal, SAW or bulk acoustic wave transducer, yttrium iron garnet resonator, or ceramic disk resonator to name a few [43,147,148]. IC resonant oscillators typically use LC tanks, although they are often designed to work in concert with an external 874 E. PANKRATZ AND E. SÁNCHEZ-SINENCIO ! ss t ð Þ correspond to the roughly circular trajectory in the figure called a limit cycle [150].Figure 4. Optoelectronic delay-line oscillator. 876 E. PANKRATZ AND E. SÁNCHEZ-SINENCIO For some subtleties of amplitude-noise behavior, see [50,143], where [50] also points out effects of not employing Floquet normalization (cf. Section 4.7).½ =fVoigt ð Þ 2(Gaussian) at small offsets [78,151,152,154]. Chorti also observed that, in general, noise processes with long correlation times tend to create such 'Gaussian' voltage spectra for small frequency offsets f m [151,152]. 4 Note well that, technically, defining spectra for f proves problematic, as it is not stationary and, what is worse, not bounded. This is in fact one reason why the ...

“…The ring oscillator [2,11,12,22,35,36] has a very short start-up time because of its low quality factor, which is important for low-power high-data-rate UWB applications. However, the oscillation frequency can be limited by power consumption and CMOS technology.…”

Section: Current-starved Ring Oscillatormentioning

confidence: 99%

A 5‐GHz energy‐efficient tunable pulse generator for ultra‐wideband applications using a variable attenuator for pulse shaping

El-Gabaly

Saavedra

2011

SUMMARYA new energy-efficient tunable pulse generator is presented in this paper using 0.13-mm CMOS technology for short-range high-data-rate 3.1-10.6 GHz ultra-wideband applications. A ring oscillator consisting of current-starved CMOS inverters is quickly switched on and off for the duration of the pulse, and the amplitude envelope is shaped with a variable passive CMOS attenuator. The variable passive attenuator is controlled using an impulse that is created by a low-power glitch generator (CMOS NOR gate). The glitch generator combines the falling edge of the clock and its delayed inverse, allowing the duration of the impulse to be changed over a wide range (500-900 ps) by varying the delay between the edges. The pulses generated with this technique can provide a sharp frequency roll off with high out-of-band rejection to help meet the Federal Communications Commission mask. The entire circuit operates in switched mode with a low average power consumption of less than 3.8mW at 910 MHz pulse repetition frequency or below 4.2 pJ of energy per pulse. It occupies a total area of 725Â600mm 2 including bonding pads and decoupling capacitors, and the active circuit area is only 360Â200mm 2 .