A 0.3-to-8.5GHz frequency synthesizer based on digital period synthesis

This paper presents a wide-band digital frequency synthesizer based on digital period synthesis (DPS). As a direct frequency synthesis method, the DPS architecture achieves inherently wide operational band, high frequency resolution and instantaneous settling. The frequency synthesizer, including reference delay-locked loop (DLL), DPS unit, and frequency multiplying DLL, was implemented in a 65-nm CMOS process and it occupies an active area of 0.3 mm2. The implemented frequency synthesizer covers a frequency range from 0.3 GHz to 8.5 GHz with 1 Hz frequency resolution, 550 fs integrated jitter, and 0.9 μs settling time.