Article ID: 000075902 Content Type: Troubleshooting Last Reviewed: 09/11/2012

Why does the Quartus II software report a VCO frequency that is less than the fVCO (PLL VCO operating range) as shown in the device Datasheet?

Environment

BUILT IN - ARTICLE INTRO SECOND COMPONENT
Description

The VCO frequency reported by the Quartus® II software in the PLL summary section of the compilation report takes into consideration the VCO post-scale counter K value. Therefore, if the counter K has a value of 2, the frequency reported will be the VCO frequency divided by two, and this can be lower than the fVCO specification.

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