Question
I am looking for high speed 14bit DAC (0 to 30MHz) with output voltage swing
(prefer adjustable)of [-0.5v to 3v].
Please also advise if AD9774 DAC can be used with load resistor greater than
50ohm in order to achieve required output swing.
May be some analog driver have to be used after DAC in order to fulfill above
requirements.
Answer
The maximum output compliance range of the AD9774 is 1.25V so there is no way
to get 3V from the part. Also there is no way to get a negative voltage if you
terminate the output resistor to ground.
A high speed op amp like the AD8055 can be used to convert the differential
current output signal of the AD9774 into a single-ended voltage output that
your question implies.
AD8130 may provide a convenient solution to differential-signle ended
conversion as it has a high inpedance Vref input allowing you to offset the
output voltage by a user-defined amount. See the AD8130 datasheet page 34 for
more details.