A 1.8GHz Spur-Cancelled Fractional-N Frequency Synthesizer with LMS-Based DAC Gain Calibration

Abstract

A 1.8GHz wideband fractional-N synthesizer achieves the phase noise of an integer-N PLL using a noise-cancellation DAC calibrated with an adaptive LMS spur correlation technique. It exhibits in-band and integrated phase noises of -98dBc/Hz and 0.8deg, respectively. The chip in 0.18mum CMOS occupies 2mm2, and consumes 29mW at 1.8V