Can I change voltage reference on AD9832 to 4 volt instead of 1.21 volt by using external voltage reference?
And I recalculate Rset=12.5 Kohm while on Iout pin Rload=1 Kohm
No - there is a max output current of nominal 4mA.
So you will need to buffer the output with a high speed amp. Amp selection depends on freq / gain required.
Retrieving data ...