PLL Integer mode vs Fractional modes in PLLs (Cyclone10 transceiver)

Hi, sorry to keep you waiting.

Arria 10 FPGA has 2 types of PLL : Fractional and Integer PLL.

Fractional PLL is used when you want to generate a uncommon clock frequencies with fractional numbers such as 6.625Mhz, 3.125Mhz etc clock frequency.

Integer PLL is used when you want to generate a common clock frequencies like 10Mhz, 25Mhz, 125Mhz etc.

how to use and set fractional PLL is shown in this link:

https://www.intel.com/content/dam/altera-www/global/ja_JP/pdfs/literature/an/an661.pdf

https://www.intel.com/content/www/us/en/docs/programmable/683640/current/implementing-fractional-pll-reconfiguration-33682.html

and this document shows how to calculate Fractional PLL divider value during setup:

https://www.intel.com/content/dam/altera-www/global/en_US/kdb/rd08062012_921/how_fractional_divisor_is_calculated_in_quartus_rev4.pdf

while integer PLL is more straight forward setup, this is the documentation of it :

https://www.intel.com/content/www/us/en/docs/programmable/683359/17-0/altera-phase-locked-loop-ip-core-user-guide.html

If you are new to PLL in Intel FPGA, I would suggest you to get familiar with integer PLL first, then slowly move to Fractional PLL.

best regards,
Farabi