Got no ans in DDS section, I try again posting here.
Sorry for doubling.
In my design I am evaluating the possibility to involve an AD9958 as DDS.
The output of the DDS is in the range 90 - 180 MHz. Each output is transformed in single-ended by means of a Balun (TCM4-6T), and than filtered with a Band Pass Chebyshev Filter and than applied to a device (LTC6945) that require 2Vp-p typical input signal level.
I'm not very familiar with DAC output, therefore I would ask:
- what is the voltage level that I should expect after the Balun when the two DDS differential outputs are coupled together?
- is this level enough to drive the LTC6945?
In case the voltage level is not enough to drive the LTC6945, could you please suggest an amplifier to match the AD9958 output with the LTC6945 input?
Referring to Page 18 of this datasheet:
If you set up the DAC as it is in Figure 32, and program a 10mA full-scale current, you'll have +/-500mV of amplitude (1Vpp) before the filter.
While I haven't checked the LTC6945, the amplitude should be enough, but it will depend on how lossy the filter is, as well as how well-centered the bandpass frequency is.