JAJSO87 may 2023 LMK04368-EP
PRODUCTION DATA
Two types of 0-delay mode are supported.
Cascaded 0-delay mode establishes a fixed deterministic phase relationship of the phase of the PLL2 input clock (OSCIN) to the phase of a clock output selected by the feedback mux. The 0-delay feedback uses internal feedback from the CLKOUT6, CLKOUT8, or SYSREF. The 0-delay feedback can also be from an external feedback through the FBCLKIN pins. The FB_MUX selects the feedback source. The OSCIN has a fixed deterministic phase relationship to the feedback clock, therefore OSCout will also have a fixed deterministic phase relationship to the feedback clock. In this mode, PLL1 input clock (CLKINx) also has a fixed deterministic phase relationship to PLL2 input clock (OSCIN); this results in a fixed deterministic phase relationship between all clocks from CLKINx to the clock outputs.
Nested 0-delay mode establishes a fixed deterministic phase relationship of the phase of the PLL1 input clock (CLKINx) to the phase of a clock output selected by the feedback mux. The 0-delay feedback uses internal feedback from the CLKOUT6, CLKOUT8, or SYSREF. The 0-delay feedback can also be from an external feedback through the FBCLKIN port. The FB_MUX selects the feedback source.
Without using 0-delay mode, there will be n possible fixed phase relationships from clock input to clock output depending on the clock output divide value.
Using an external 0-delay feedback reduces the number of available clock inputs by one.