What is the difference between PCLKT and PLLT as dedicated PLL reference clock?
Both PCLKT and PLLT are legal pin to use as PLL reference clock however there are differences on the clock paths that should take note in designing certain applications.
PCLKT Pin:
Provides a direct connection to the global and regional clock networks, which are suitable sources for driving the PLL reference clock (PLL refclk).
PLLT Pin:
Offers a more direct path to the PLL itself, bypassing the global and regional clock networks. This makes it preferable for highly sensitive applications due to generally lower clock skew and reduced jitter.