An RC-Based Dual Injection Locked Delay Cell for High-Frequency Ring VCOs

This paper proposes an RC-based dual injection-locked (RC-DIL) delay cell for a coupled ring voltage-controlled oscillator (RVCO). The RC-DIL delay cell uses an RC network instead of PMOS cross-coupled architecture. It reduces the power dissipation of the delay cell and the overall RVCO. The RC-DIL delay cell employs two NMOS transistors for injection lock, a technique utilized to generate a poly-phase response within the RVCO, and for coupling two RVCOs to maximize the operating frequency range. This RC-DIL delay cell further improves the operating frequency because of the extra discharging path from the RVCO's output node, which reduces the discharging time. The post-layout and Monte Carlo simulations of the RC-DIL delay cell-based RVCO are performed in 65 nm CMOS technology using 1 V supply. The power dissipation and the phase noise of the RC-DIL delay cell-based RVCO is 3.6mW and -96.6 dBc/Hz at 1 MHz offset frequency. The power dissipation is improved by 63.8% in RC-DIL delay cell-based RVCO compared to conventional RVCO. The figure of merits (FoMs) i.e. FoM
1
, FoM
T
(including tuning range), and FoM
N
(including the number of phases) of RC-DIL delay cell-based RVCO, are - 160.2 dBc/Hz, -174.5 dBc/Hz, and -185.2 dBc/Hz which are 5.9 dB, 15.1 dB, and 14 dB better than conventional RVCO.