Now showing 1 - 10 of 10
  • Publication
    A 60 GHz Frequency Generator Based on a 20 GHz Oscillator and an Implicit Multiplier
    This paper proposes a mm-wave frequency generation technique that improves its phase noise (PN) performance and power efficiency. The main idea is that a fundamental 20 GHz signal and its sufficiently strong third harmonic at 60 GHz are generated simultaneously in a single oscillator. The desired 60 GHz local oscillator (LO) signal is delivered to the output, whereas the 20 GHz signal can be fed back for phase detection in a phase-locked loop. Third-harmonic boosting and extraction techniques are proposed and applied to the frequency generator. A prototype of the proposed frequency generator is implemented in digital 40 nm CMOS. It exhibits a PN of -100 dBc/Hz at 1 MHz offset from 57.8 GHz and provides 25% frequency tuning range (TR). The achieved figure-of-merit (FoM) is between 179 and 182 dBc/Hz.
      429Scopus© Citations 87
  • Publication
    A Fully Integrated Bluetooth Low-Energy Transmitter in 28 nm CMOS With 36% System Efficiency at 3 dBm
    We propose a new transmitter architecture for ultra-low power radios in which the most energy-hungry RF circuits operate at a supply just above a threshold voltage of CMOS transistors. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply voltage and power without sacrificing its startup margin. It also reduces 1/f noise and supply pushing, thus allowing the ADPLL, after settling, to reduce its sampling rate or shut it off entirely during a direct DCO data modulation. The switching power amplifier integrates its matching network while operating in class-E/F2 to maximally enhance its efficiency at low voltage. The transmitter is realized in 28 nm digital CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5 mW while delivering 0 dBm/3 dBm RF power in Bluetooth Low-Energy mode.
      682Scopus© Citations 62
  • Publication
    A 60 GHz 25% tuning range frequency generator with implicit divider based on third harmonic extraction with 182 dBc/Hz FoM
    A 60 GHz frequency generator with implicit ÷3 divider is proposed in this work to improve the system-level efficiency and phase noise. A third-harmonic boosting technique is utilized to simultaneously generate 20GHz and sufficiently strong 60 GHz signals in order to avoid any divider operating at 60 GHz. The prototype is fabricated in 40nm CMOS and exhibits a phase noise of −100 dBc/Hz at 1MHz offset from 60 GHz carrier and 25% tuning range. The phase noise and FoMT (figure-of-merit with tuning range) are improved by 5 dB and 4.6 dB, respectively, compared to state-of-the-art.
      442Scopus© Citations 11
  • Publication
    A 1/f noise upconversion reduction technique applied to class-D and class-F oscillators
    The 1/f (flicker) noise upconversion degrades the close-in spectrum of CMOS RF oscillators. The resulting 1/f3 phase noise (PN) can be an issue in PLLs with a loop bandwidth of <;1MHz, which practically implies all cellular phones. A previously published noise-filtering technique [1] and adding resistors in series with gm-device drains [2] have shown significant reduction of the 1/f3 oscillator PN corner. However, the former needs an additional tunable inductor and the latter degrades PN in the 20dB/dec region.
      970Scopus© Citations 35
  • Publication
    A 1/f noise up-conversion reduction technique for voltage-biased RF CMOS oscillators
    In this paper, we propose a method to reduce a flicker (1/f) noise upconversion in voltage-biased RF oscillators. Excited by a harmonically rich tank current, a typical oscillation voltage waveform is observed to have asymmetric rise and fall times due to even-order current harmonics flowing into the capacitive part, as it presents the lowest impedance path. The asymmetric oscillation waveform results in an effective impulse sensitivity function of a nonzero dc value, which facilitates the 1/f noise upconversion into the oscillator's 1/f3 phase noise. We demonstrate that if the ω0 tank exhibits an auxiliary resonance at 2ω0, thereby forcing this current harmonic to flow into the equivalent resistance of the 2ω0 resonance, then the oscillation waveform would be symmetric and the flicker noise upconversion would be largely suppressed. The auxiliary resonance is realized at no extra silicon area in both inductor-and transformer-based tanks by exploiting different behaviors of inductors and transformers in differential-and common-mode excitations. These tanks are ultimately employed in designing modified class-D and class-F oscillators in 40 nm CMOS technology. They exhibit an average flicker noise corner of less than 100 kHz.
      538Scopus© Citations 97
  • Publication
    A wideband 60 GHz class-E/F2 power amplifier in 40nm CMOS
    This paper presents a fully integrated 60 GHz power amplifier in 40nm CMOS that reaches the highest reported product of power-added efficiency and bandwidth. It is achieved through low/moderate coupling-factor transformers in the preliminary stages and a proper second harmonic termination of the output stage, such that it can operate as a class-E/F2 switched-mode PA at the saturation point. The three-stage PA delivers 17.9dBm saturated output power with 20% peak PAE. It demonstrates a bandwidth of 9.7 GHz with a peak gain of 21.6 dB.
      755Scopus© Citations 18
  • Publication
    A Class-F CMOS Oscillator
    An oscillator topology demonstrating an improved phase noise performance is proposed in this paper. It exploits the time-variant phase noise model with insights into the phase noise conversion mechanisms. The proposed oscillator is based on enforcing a pseudo-square voltage waveform around the LC tank by increasing the third-harmonic of the fundamental oscillation voltage through an additional impedance peak. This auxiliary impedance peak is realized by a transformer with moderately coupled resonating windings. As a result, the effective impulse sensitivity function (ISF) decreases thus reducing the oscillator's effective noise factor such that a significant improvement in the oscillator phase noise and power efficiency are achieved. A comprehensive study of circuit-to-phase-noise conversion mechanisms of different oscillators' structures shows the proposed class-F exhibits the lowest phase noise at the same tank's quality factor and supply voltage. The prototype of the class-F oscillator is implemented in TSMC 65-nm standard CMOS. It exhibits average phase noise of -136 dBc/Hz at 3 MHz offset from the carrier over 5.9-7.6 GHz tuning range with figure-of-merit of 192 dBc/Hz. The oscillator occupies 0.12 mm2 while drawing 12 mA from 1.25 V supply.
      237Scopus© Citations 142
  • Publication
    A fully integrated 28nm Bluetooth low-energy transmitter with 36% system efficiency at 3dBm
    We propose a new transmitter (TX) architecture for ultra-low power radios. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply voltage and power without sacrificing its phase noise and startup margins. It also reduces 1/f noise allowing the ADPLL, after settling, to reduce its sampling rate or shut it off entirely during direct DCO data modulation. The switching power amplifier integrates its matching network while operating in class-E/F2 to maximally enhance its efficiency. The transmitter is realized in 28nm CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5mW while delivering 0 dBm/3dBm RF power in Bluetooth Low-Energy.
      674Scopus© Citations 10
  • Publication
    A 0.5V 0.5mW switching current source oscillator
    This paper proposes a new RF oscillator topology that is suitable for ultra-low voltage and power applications. By employing alternating current source transistors, the structure combines the benefits of low supply voltage operation of conventional NMOS cross-coupled oscillators together with high current efficiency of the complementary push-pull oscillators. In addition, the 1/f noise upconversion is also reduced. The 40nm CMOS prototype exhibits an average FoM of 189.5 dBc/Hz over 4–5 GHz tuning range, dissipating 0.5mW from 0.5V power supply, while abiding by the technology manufacturing rules.
      446Scopus© Citations 14
  • Publication
    An Ultra-Low Phase Noise Class-F 2 CMOS Oscillator With 191 dBc/Hz FoM and Long-Term Reliability
    In this paper, we propose a new class of operation of an RF oscillator that minimizes its phase noise. The main idea is to enforce a clipped voltage waveform around the LC tank by increasing the second-harmonic of fundamental oscillation voltage through an additional impedance peak, thus giving rise to a class-F 2 operation. As a result, the noise contribution of the tail current transistor on the total phase noise can be significantly decreased without sacrificing the oscillator's voltage and current efficiencies. Furthermore, its special impulse sensitivity function (ISF) reduces the phase sensitivity to thermal circuit noise. The prototype of the class-F 2 oscillator is implemented in standard TSMC 65 nm CMOS occupying 0.2 mm 2 . It draws 32-38 mA from 1.3 V supply. Its tuning range is 19% covering 7.2-8.8 GHz. It exhibits phase noise of -139 dBc/Hz at 3 MHz offset from 8.7 GHz carrier, translated to an average figure-of-merit of 191 dBc/Hz with less than 2 dB variation across the tuning range. The long term reliability is also investigated with estimated >10 year lifetime.
      357Scopus© Citations 66