PLL Lock Time of CPLL in CY2291/CY2292

Question: Why does the CPLL on the CY2291 or CY2292 have a longer lock time than the UPLL or SPLL?

 

Answer:

The CPLL has a slew limiter to smooth out frequency transitions when the select lines S2, S1 and S0 are changed.  The slew rate for the CPLL is a min of 1MHz/ms to a max of 20MHz/ms as opposed to a 1ms lock time for the UPLL and SPLL.