A Fractional-N Digital LC-PLL Using Coupled Frequency Doubler With Frequency-Tracking Loop for Wireline Applications A 224-Gb/s DAC-Based PAM-4 Quarter-Rate Transmitter With 8-Tap FFE in 10-nm FinFET Wandering Spur Suppression in a 4.9-GHz Fractional-N Frequency Synthesizer Phase Noise Reduction in LC VCO’s Using an Array of Cross-Coupled Nanoscale MOSFETs and Intelligent Post-Fabrication Selection An Ultra-Low Jitter, Low-Power, 102-GHz PLL Using a Power-Gating Injection-Locked Frequency Multiplier-Based Phase Detector