Fast frequency acquisition all-digital PLL using PVT calibration

Hae-Soo Jeon, Duk-Hyun You, In-Cheol Park
2008 2008 IEEE International Symposium on Circuits and Systems  
Fast frequency acquisition is crucial for phase-locked loops (PLLs) used in portable devices, as on-chip clocks are frequently scaled down or up in order to manage power consumption. This paper describes a new frequency acquisition method that is effective in all-digital PLLs (ADPLLs). To achieve fast frequency acquisition, the codeword of the digitally controlled oscillator (DCO) is predicted by measuring the variations of process, supply voltage and temperature (PVT). A PVT sensor implemented
more » ... sensor implemented with a ring oscillator is employed to monitor the variations. As the sensor frequency at the current operating condition is directly related to the PVT variations, the sensor frequency is taken into account to compensate such variations in predicting the DCO codeword. The proposed method enables one-cycle frequency acquisition, and the frequency error is less than 1.5%. The proposed ADPLL implemented in a 0.18µm CMOS process operates from 150MHz to 500MHz and occupies 0.075mm 2 . I.
doi:10.1109/iscas.2008.4541995 dblp:conf/iscas/JeonYP08 fatcat:uymqj5rglvbzpg7rd3stjcg7si