The Spread Spectrum PLL is a high performance PLL based Spread Spectrum Clock Generator implemented using a digital CMOS technology. It is highly integrated and requires no external components. Differential circuit techniques are employed to attain low jitter in the noisy environment typical of multi-million gates digital chip. The Spread Spectrum PLL generates 2 clocks from a single reference clock, each with 50% Duty Cycle. Depending on the mode of operation these clocks are Spread Spectrum Modulated or unmodulated.