LC8900KQ Datasheet, PDF (6/12 Pages) Sanyo Semicon Device – Digital Audio Interface Receiver

PLL VCO Functional Circuit Block
VCO
LC8900KQ
• The VCO (Voltage Controlled Oscillator) functional block consists of multiple ring oscillator ad shown above.
• The ring oscillator produces the frequencies from 3 MHz to 40 MHz according to the VCO pin voltages 0 V to 3 V.
• The VCO self oscillation frequency is determined by the VIN pin voltage.
Phase Detector
• The phase detector circuit operates on the rising edge of the incoming signals. It compares the clock generated from
the input signal with the VCO clock.
LPF (Low-pass filter)
• The charge pump and the LPF are shown above. The LPF time constant varies depending on the lock judge signal.
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