VCO Frequency and MF Value - 2023.1 English

H.264/H.265 Video Codec Unit v1.2 Solutions LogiCORE IP Product Guide (PG252)

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2023.1 English

The VCO operating frequency can be determined by using the following relationship:

fvco = frefclk × M


fclkout = fvco / O

where, M corresponds to the integer feedback divide value and O corresponds to the value of output divide.

Note: The PLL does not support fractional divider values.
Important: Select the PLL feedback multiplier value based on the supported VCO frequency range (fvco).

Refer to the Zynq UltraScale+ MPSoC Data Sheet: DC and AC Switching Characteristics (DS925) for more information on the operating range of fvco.

Select the output divider (O) based on the required core clock or MCU clock frequency.

Sharing VCU clock inputs with other IP can result in clock jitter that may degrade VCU performance or image quality.