Two 122-GHz Phase-Locked Loops in 65-nm CMOS Technology

Two 122-GHz phase-locked loops (PLLs) have been developed based on a 65-nm Si CMOS technology, and their performances are compared. For the first PLL, a voltage-controlled oscillator (VCO) with a frequency doubler embedded in the oscillator core was employed (PLL1), while the second PLL employs a push-push VCO (PLL2). The output powers of PLL1 and PLL2 were -8.6 and -21.9 dBm near 122 GHz, obtained from dc power dissipation of 82.9 and 87.7 mW, respectively. The respective locking ranges were measured to be 121.9-122.2 and 122.7-122.9 GHz for PLL1 and PLL2. The in-band phase noises were -59.2 and -60.1 dBc/Hz at 10-kHz offset, and the out-band phase noises were -102.4 and -99.5 dBc/Hz at 10-MHz offset for PLL1 and PLL2, respectively. The chip sizes were 1000 × 760 μm^² (PLL1) and 1300 × 840 μm² (PLL2) including probing pads.