A 0.2–11.7GHz, high accuracy injection-locking multi-phase generation with mixed analog/digital calibration loops in 28nm FDSOI CMOS

An injection-locked ring oscillator (ILRO) leveraging mixed analog/digital calibration loops for high-accuracy 8-phase clock generation is proposed. A phase detector (PD) based on passive mixers measures the quadrature error and continuously tunes the oscillator for fine phase correction. Concurrently, a window comparator monitors the PD output and drives digital coarse calibration in background. The ILRO maintains high phase accuracy over a wide operation frequency range and large supply and temperature variations. The chip is fabricated in 28nm FDSOI CMOS and with power consumption from 3mW to 15mW, measurements demonstrate a 0.2–11.7GHz frequency range with better than 1.5° quadrature phase error over ±20% supply and −40×120°C temperature variations. Measured performances meet the requirements of 1-to-45Gb/s quarter-rate multi-standard I/O receivers.