A Low-Phase-Noise and Wide-Tuning-Range CMOS/IPD Transformer-Based VCO With High $\mathrm {FOM}_{T}$ of −206.8 dBc/Hz

This paper presents a low-phase-noise and wide-tuning-range voltage-controlled oscillator (VCO) implemented in a standard 0.18-μm complementary metal-oxide-semiconductor (CMOS) process with an integrated passive device (IPD) transformer. Even- and odd-mode oscillations of the transformer-based resonator can be achieved by the mode-switching topology, and the oscillations in the two modes result in a wide tuning range of the VCO. Moreover, the IPD-based transformer achieves high-quality (Q) factors (Q >30), which is impractical in standard CMOS-based technologies due to their lossy silicon substrate. The high-Q IPD transformer reduces the phase noise of the VCO and, therefore, leads to a superior figure-of-merit (FOM) and FOM including the tuning range (FOM
_T
). Operating at 0.8 V supply voltage, the VCO consumes 9.2-mW dc power. At this bias condition, the measured phase noise is -124.2 dBc/Hz at 1-MHz offset from the 6.26-GHz oscillation frequency. Furthermore, the VCO exhibits a 65.7% tuning range and the flipped CMOS chip is packaged on the IPD substrate with a footprint area of 4.35 mm
²
. Compared with previously published CMOS-based VCOs, the presented VCO features excellent performances in phase noise, wide tuning range, FOM, and FOM
_T
.