Now showing 1 - 2 of 2
  • Publication
    A Low-Flicker-Noise 30-GHz Class-F23 Oscillator in 28-nm CMOS Using Implicit Resonance and Explicit Common-Mode Return Path
    (Institute of Electrical and Electronics Engineers (IEEE), 2018-04-24) ; ;
    This paper presents a millimeter-wave (mmW) frequency generation stage aimed at minimizing phase noise (PN) via waveform shaping and harmonic extraction while suppressing flicker noise upconversion via proper harmonic terminations. A 2nd-harmonic resonance is assisted by a proposed embedded decoupling capacitor inside a transformer for explicit common-mode current return path. Class-F operation with 3rd-harmonic boosting and extraction techniques allow maintaining high quality factor of a 10-GHz tank at the 30-GHz frequency generation. We further propose a comprehensive quantitative analysis method of flicker noise upconversion mechanism exploiting latest insights into the flicker noise mechanisms in nanoscale short-channel transistors, and it is numerically verified against foundry models. The proposed 27.3- to 31.2-GHz oscillator is implemented in TSMC 28-nm CMOS. It achieves PN of -106 dBc/Hz at 1-MHz offset and figure-of-merit (FoM) of -184 dBc/Hz at 27.3 GHz. Its flicker phase-noise (1/f3) corner of 120 kHz is an order-of-magnitude better than currently achievable at mmW.
    Scopus© Citations 101  628
  • Publication
    Intuitive Understanding of Flicker Noise Reduction via Narrowing of Conduction Angle in Voltage-Biased Oscillators
    (Institute of Electrical and Electronics Engineers (IEEE), 2019-01-30) ; ;
    This brief aims to intuitively explain and numeri- cally verify the observed phenomenon of flicker noise reduction in oscillators of reduced conduction angle (i.e., in class-C), which has been presented in literature but never properly explained. The flicker phase noise in a voltage-biased oscillator capable of operating in class-B and class-C is compared and numerically verified using a commercial simulation model of TSMC 28-nm CMOS. We illustrate how narrowing the conduction angle can suppress the 1/f noise up-conversion by decreasing 1/f noise exposure to the asymmetric rising and falling edges of oscillation waveform. The effects of implicit common-mode tank in the class- C operation is also discussed. We further clarify ambiguities among several simulation methods of impulse sensitivity function (ISF) based on periodic small-signal analysis (PAC or PXF), which is a key tool in understanding the flicker noise up- conversion. A clearer ISF simulation method based on positive sidebands of PXF is proposed.
    Scopus© Citations 25  603