CT20900 is a PLL providing 33, 66, 50 and 200MHz clocks based on a 25MHz reference clock. It comprises a Phase Frequency Detector with internal charge pump that detects the phase difference between the 25MHz reference clock and the divided by 8 version of the 200MHz clock generated by the Voltage Controlled Oscillator (VCO).
The loop includes a second order Low Pass Filter (LPF)