I am using an AD9958 and trying to run my SYSCLK at 500MHz from a 100MHz source (M=5)
I just noticed that the VCO Gain Control is recommended to be set at this and I have been using it without setting it
My question is (before I go and set that bit), if I am attempting a 500MHz system clock without that bit set, is it possible for my values to get messed up? I am writing out the values for my start frequency in a linear sweep correctly (CFTW, R04), but in reality my starting frequency is half of what I've written out (i.e. I want 30MHz, I'm seeing 15MHz). Now I'm not ruling out an SPI error/hiccup, but I haven't had any problems so far with my SPI Controller.
Would not setting that gain control bit result in a slower system clock, and in return a different SYSCLK that's used in calculations? I've noticed that the range is 255-500, and 255 is pretty close to half of 500