An Ultra-low-voltage CMOS VCO Using Parallel Capacitor for Phase Noise Reduction

In this work, a 7.92GHz ultra-low-voltage LC-tank voltage controlled oscillator (VCO) is introduced. The proposed LC-tank VCO adopts a NMOS cross-coupled topology and additional parallel capacitors for low voltage operation and phase noise reduction. The measured phase noise at 600KHz frequency ofiset is i98dBc/Hz and at 1MHz ofiset is i108dBc/Hz, respectively. The proposed VCO achieves a flgure-of-merit (FOM) value of i187dBc/Hz, drawing 0.87mW from a 0.62V supply. The proposed circuit topology is designed for ultra wide-band (UWB) applications and implemented in TSMC 0.18"m 1P6M CMOS technology.

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