Part Number:DAC38RF82
Hello,
i want to use the DAC38RF82 to generate baseband IQ signals. Thus I have to DC couple my signal path and can not put any capacitors into this path. After solving the issue with biasing the dac output (use two 50 Ohm resistors and a hight enough voltage so you have 1V8 at the DAC ouputs), I have question about the common mode voltage at the DAC ouput.
If I am not mistaken, I've read that the DAC has to have 1V8 common mode at its outputs to deliver the best performance. My problem is that I have to interface an IC that requires 0V common mode at its differential input. For baseband signals capacitors can not be used in the signal path. I tried to use the LMH6401 and LMH3401 and shift the common mode to 0V. It works quite well but it distores the signal(SFDR=40dBc @ 250MHz). Is there another way to shift the common mode to 0V or to reduce the distortion of the LMH6401/LMH3401?
Thanks!