Synchronized feed forward frequency decoder and scalable voltage controlled oscillator for fractional-n phase locked loop

A scalable voltage-controlled oscillator (VCO) comprising:

• an array of ring cells, wherein each of the ring cells comprises a multi-stage ring VCO comprising a plurality of inverters;
• a digital-to-analog (DAC) converter configured to generate first and second bias voltage signals, wherein a transconductance of a selected one of the ring cells is controlled by applying the first and second bias voltage signals to the selected one of the ring cells.

An apparatus comprising:

• a first circuit for generating a voltage-controlled oscillator gain sync code (KVCO_SYNC) from a feedback divider ratio and an update rate input thereto;
• a second circuit for generating a feedback divider ratio sync code (FBDIV_SYNC) from the feedback divider ratio input thereto;
• wherein the KVCO_SYNC code is provided to a scalable voltage-controlled oscillator (VCO) for controlling operation thereof, and wherein the KVCO_SYNC code and the FBDIV_SYNC code are provided to a fractional divider for controlling operation thereof.