1.2-17.6 GHz Ring-Oscillator-Based Phase-Locked Loop with Injection Locking in 65 nm Complementary Metal Oxide Semiconductor

A wide-frequency-range phase-locked loop (PLL) with subharmonic injection locking is proposed. The PLL is equipped with a wide tunable ring-type voltage-controlled oscillator (ring VCO), frequency dividers, and a doubler in order to the widen injection-locked tuning range (ILTR). In addition, high-frequency injection signals are used to improve phase noise, which is supposed to be generated by a reference PLL. The proposed circuit is fabricated by using a 65 nm Si complementary metal oxide semiconductor (CMOS) process. The measured frequency tuning range is from 1.2 to 17.6 GHz with a frequency doubler and dividers. The phase noise at 14.4 GHz (= 32 x 450 MHz) with injection locking was -109 dBc/Hz, which shows a 21-dB reduction compared with that in the case without injection locking. (C) 2012 The Japan Society of Applied Physics