All digital phase-locked loop using active inductor oscillator and novel locking algorithm

A fast locking all-digital phase-locked loop (ADPLL) with the active inductor oscillator is proposed. An LC-tank DCO with a tunable active inductor can obtain a wider operational frequency range, smaller area and higher signal quality. The proposed frequency and phase locking algorithm can achieve good jitter performance, high frequency accuracy, and low circuit complexity. The ADPLL is designed using a 0.18 um CMOS process. The operational frequency range of the ADPLL is from 318 MHz to 458 MHz. The RMS and the peak-to-peak jitters at 402 MHz are 4.2 ps and 94 ps, respectively. The core size is 390×390 um². The power consumption is 5.4 mW at 416 MHz.