For 40mA output and assuming 50ohm termination, the max output power is 10dBm for a sine wave. The NSD is specified as -165dBm/Hz which implies a noise floor of -175dBFS/Hz. Is that conversion correct? What is the dominant noise source in this DAC?
Ideally, increasing the output current by cascading multiple DACs to get more current out would increase the output power and the dBFS/Hz. Is it feasible to stack multiple DACs to get more current/voltage out?