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AD9952 Crystal Out Buffer Specs and DAC Output

Question asked by jbschmidt on May 4, 2018
Latest reply on Jun 11, 2018 by KennyG



I am using 2 DDSs on a custom 4 layer PCB. An issue I am having is the crystal out buffer is unable to produce a 25 MHz output with no load (with the exception of the probe). The output is a triangle wave at 25 MHz. Would it be possible to get some specs on the crystal out buffer? There is no information in the datasheet about it. Additionally, a DDS DAC output is not functional. One of the DDS on the board works fine, and both can be programmed. A difference from the eval schematic is that the loads are 25 Ohm resistors to VDD (1.8 V) and not 50 Ohm. The DAC output was originally working, but then no longer produced an output. I am aware that operating outside the compliance range can damage the circuitry. However, I am wondering if there is any other possible dependencies that could influence the output behavior of the DAC.