A 5.2GHz Trifilar Transformer-Based Class-F23 Noise Circulating VCO with FoM of 192.6 dBc/Hz

Hanzhang Cao1; Tongde Huang1; Xiaolong Liu2; Hao Wang1; Jin Jin1; Wen Wu1

10.1109/A-SSCC58667.2023.10347969

2023

979-8-3503-3004-5

2023 IEEE Asian Solid-State Circuits Conference (A-SSCC)

1-3

5-8 Nov. 2023

Haikou, China

With the development of wireless communication, high-speed data transmissions require a pure local oscillation signal produced by a voltage-controlled oscillator (VCO). A variety of circuit technologies is developed for improving the LC-VCO's phase noise. The harmonic shaping technology represented by class-F23 VCO in Fig. 1 (top left) utilizes the transformer-based multi-order load in differential mode (DM) to shape the oscillation waveform [1]. From the perspective of the impulse sensitivity function (ISF) [2], the harmonic shaping technology reshapes the ISF waveform to inhibit noise conversion to phase noise. As a result, the low root-mean square (RMS) value of the effective ISF decreases the flicker noise up-conversion to 1/f3 phase noise. However, the phase noise in the harmonic shaping oscillators is limited by the magnitude of the noise sources injected into the oscillator. Specifically, during the switching transition, much more noise flows into the tank, deteriorating the phase noise performance. Yet, the noise circulating (NC) technology shown in Fig. 1 (top middle) can effectively lower the noise source injected into the oscillator by source degeneration [3]–[4]. During the zero-crossing of the tank voltage, the noise current partially flows into the resonant tank while most of them still circulates within the transistors, thus reducing the magnitude of the noise source effectively. However, the noise circulating oscillators fail to guarantee a resistively loaded CM path. The parasitic capacitance at source nodes introduces an extra capacitive noise flow path to the resonant tank, which causes flicker noise up-conversion. Besides, the technology usually adopts a cross-coupled pair as the active core, bringing in a unit gain between the gate and drain of the transistor and contributing little to reduce the phase noise. The drain and the gate share the same DC bias voltage, leading to a severe frequency pushing effect due to the voltage-dependent gate parasitic capacitance [5]. For the LC oscillator, the total effective noise produced by the $i$th devices can be expressed as \begin{equation*}\sum\limits_{i}N_{L, i}=\frac{1}{2N^{2}\pi}\sum\limits_{i}\int\nolimits_{0}^{2\pi}\Gamma_{i}^{2}(\theta)\overline{i_{n, i}^{2}(\theta)}d\theta\tag{1}\end{equation*} where $i_{n, i}^{2}(\theta)$ is the power spectral density (PSD) of the noise source, and $\Gamma_{i}(\theta)$ is the corresponding ISF. Equation (1) indicates that the phase noise of the oscillator is mainly determined by the magnitude of the noise sources and the noise sources' conversion to the phase noise.

Phase noise Wireless communication Voltage-controlled oscillators Voltage Logic gates Harmonic analysis Transformers

其他

EI

20240315390281

Capacitance ; Circuit oscillations ; Electric loads ; Harmonic analysis ; Oscillistors ; Variable frequency oscillators

Electricity: Basic Concepts and Phenomena:701.1 ; Magnetism: Basic Concepts and Phenomena:701.2 ; Electric Networks:703.1 ; Electric Power Systems:706.1 ; Oscillators:713.2 ; Numerical Methods:921.6

IEEE

1.Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology, China
2.School of Microelectronics, Southern University of Science and Technology, China

Hanzhang Cao,Tongde Huang,Xiaolong Liu,et al. A 5.2GHz Trifilar Transformer-Based Class-F23 Noise Circulating VCO with FoM of 192.6 dBc/Hz[C],2023:1-3.