Use An External Divider In The Feedback Loop For RoboClockII
Last Updated: 12/05/2013
Can an external divider be used in a feedback loop?
The RoboClockII (CY7B993/4V) has internal divide capability of up to divide-by-twelve. If a higher divide ratio is needed, it is possible to use external dividers in the feedback path. However, large dividers or dividers that have an inherently long delay so they should be used cautiously.
There are some constraints that should be followed. A large divider ratio can cause the phase detector update gaps to become excessively large. As a rule of thumb the maximum divider ratio in the feedback path should be less than 16. Larger values are not recommended. The maximum time delay permitted in the external feedback loop is 10 ns.