LMK04832EVM: generating 1000Mhz reference clock using 100Mhz VCO

Hi,

I'm using the LMK04832EVM with a 100 MHz VCO , replacing the original  122.88 MHz VCO.

In order to generate all of the required different outputs rates, I need a reference clock of 1000 MHz (2000 MHz is also OK).

I've tried , using TICS Pro, to configure such a frequency, by changing the , R Divider, N divider and N prescaler, and was unable to get a PLL lock.

I've only managed to generate 2400,2500,2600 MHz ref clocks (maybe some other as well).

Can someone help me understand what combination of N & R is needed in order to generate the required frequency? 

Thank you,

Gilad