A 74GHz–80GHz 1.2GHz/µs-Slope 20.9mW FMCW Synthesizer with TDC-Gain-Independent Loop-Bandwidth Employing a TDC-Offset-Free Type-II Digital PLL and a Linearized Hybrid-Tuning DCO

A 74–80 GHz self-adapted sawtooth-FMCW frequency synthesizer features a Type-II digital PLL with zero TDC offset independent of chirp rate, TDC-gain-independent loop bandwidth, a 25kHz-resolution glitch-free wideband linear digitally controlled oscillator (DCO) with a dedicated convergence-less digital pre-distortion (DPD). The prototype measures 6-GHz chirp bandwidth with a 1.2GHz/us slope at 77GHz while achieving 0.031% rms chirp error and consuming 20.9mW from 0.9V supply.