A VCO With Robust Implicit Common-Mode Resonance Against Nonideal Decoupling Network
Dingxin Xu, Zheng Sun, Yuang Xiong, Yuncheng Zhang, Hóngyè Huáng, Zezheng Liu, Ashbir Aviat Fadila, Atsushi Shirane, Kenichi Okada · IEEE Solid-State Circuits Letters · 2024
This letter describes a voltage-controlled oscillator (VCO) that can achieve robust flicker noise suppression when the decoupling network is not ideal. Utilizing a multi-tap transformer, the implicit common-mode (CM) impedance quality factor (Q factor) degradation from the parasitic resistance of the decoupling network can be avoided. Fabricated in 65-nm CMOS, the proposed VCO realizes a flicker corner (1/f3 corner) from 70 kHz to 230 kHz across the tuning range from 4.24 GHz to 4.80 GHz. The proposed VCO achieves a phase noise (PN) of -127.4 dBc/Hz at 1 MHz offset frequency fofst, and a figure-of-merit (FoM) of 193.1 dB. The core area of the VCO is 0.29 mm2.