A 2.3–15.8-GHz 8-Phase Injection-Ripple-Filtered Multi-Ring-Coupled DCO Enabling a Wideband Digital PLL

A high-frequency wide-range 8-phase DCO with inherent injection ripple filtering is proposed and incorporated into a wideband digital PLL. The DCO in prototype PLL achieves 2.3–15.8GHz frequency range. With the multiplication factor of 260, the PLL achieves 3–15.5GHz wideband output, −59dBc far-off injection spur at 10GHz output, and −260dB FoMN.