Hi Paul,
Not considering performance, the only limitation is the sampling rate and the interpolation filters. The maximum output frequency will be limited to about 0.4 * Fs, so at 2.5 GSPS the limit is 1 GHz. Regarding the higher Nyquist zones, this DAC does not have any special modes to accommodate other Nyquist zones. So although you could technically use them there will still be gain rolloff due to the sinx/x response. I have not done any measurements to confirm the output bandwidth of the DAC other than showing good flatness throughout the first nyquist zone.
Regards,
Matt Guibord
