TIMING-22: Missing External Delay on MMCM - 2023.2 English

Vivado Design Suite User Guide: Design Analysis and Closure Techniques (UG906)

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2023.2 English

The MMCM <cell_name> has an external feedback loop but no external delay has been specified between FBOUT and FBIN. It is recommended to specify an external delay with set_external_delay between the two ports connected to the pins FBOUT and FBIN with an external feedback loop.