SNAS522K September 2011 – December 2023 LMK03806
PRODUCTION DATA
For the PLL to operate in closed-loop mode, the following relationships in Equations 5 and 6 must be satisfied to ensure the PLL phase detector input frequencies for the reference and feedback paths are equal.
where
When FOSCin and Fpd are equal, the best PLL in-band noise can be achieved with the PLL reference doubler enabled (EN_PLL_REF_2X=1) and the PLL reference divider is 2 (PLL_R =2), rather than with the doubler disabled (EN_PLL_REF_2X=0) and PLL reference divider of 1 (PLL_R=1).
The output frequency is related to Fvco as follows.
where