Can I apply 1 GSPS for each channel so that I can have 4 channel with maximum rate of each channel is 1 GSPS? Or 1 GSPS is the total maximum rate, i.e., each channel can have maximum of 250 MSPS? Thanks!
The DAC clock is fed directly to the 4 DAC output stages. All of the DACs update at the same time, and all will be running at 1Gsps (or whatever the clock rate is).