ADF4356_REF_conditions

Regardless of frequency, it is suggested to use high slew rate references as it directly affects the jitter performance. Given specification is to make the part operational for frequencies lower than 10 MHz as it minimum input frequency spec. Part can work with low slew rate references at higher frequencies but performance will be highly degraded. Square waves are tend to have higher slew rates than sinewaves and suggested. Slew rate of sinewave is dependent on its frequency and amplitude. Increasing the amplitude of a sinewave reference will provide better slew rate and better output performance. 

Alternatives of reference sources can be evaluated and the one having the highest slew rate can be preferred.

Regardless of frequency, it is suggested to use high slew rate references as it directly affects the jitter performance. Given specification is to make the part operational for frequencies lower than 10 MHz as it minimum input frequency spec. Part can work with low slew rate references at higher frequencies but performance will be highly degraded. Square waves are tend to have higher slew rates than sinewaves and suggested. Slew rate of sinewave is dependent on its frequency and amplitude. Increasing the amplitude of a sinewave reference will provide better slew rate and better output performance. 

Alternatives of reference sources can be evaluated and the one having the highest slew rate can be preferred.