one could use one of these chips.
thay seem to b able to handle that freq's
AD9954 -- 400 MSPS 14-Bit DAC 1.8 V CMOS Direct Digital Synthesizer
AD9953 -- 400 MSPS 14-Bit DAC 1.8 V CMOS Direct Digital Synthesizer
AD9952 -- 400 MSPS 14-Bit DAC 1.8 V CMOS Direct Digital Synthesizer
AD9951 -- 400 MSPS 14-Bit DAC 1.8 V CMOS Direct Digital Synthesizer
AD9859 -- 400 MSPS 10-Bit DAC 1.8 V CMOS Direct Digital Synthesizer