In high-speed digital systems and high-resolution display devices, the jitter effect of
phase-locked loops (PLL) limits the system performance. Power supply noise coupling is
one of the major causes of PLL jitter problems, especially with mixed-signal systems.
The paper presents a targeted 5.0V 500 MHz PLL which is implemented by a 0.6 um
1P3M digital CMOS technology. The features of the proposed design include a load-optimized
3-stage VCO, a frequency limiter RC circuit, and a ratioed VCO controlling
current mirror. The jitter, thus, is reduced to 72.693 ps at 600 MHz at the presence of
supply noise, while the sensitivity is limited to 286.6 ps/V. This high-noise immunity
design allows that the PLL can be integrated with digital circuits.