I don't believe the AD9915 Narrow-Band SFDR of -95dBc. I can easily generate a case that produces -76dBc at 4KHz offset.
Kevin - Have you tried configuring the way the datasheet calls it out? Please note the -95 is a typical value not a min/max limit. It is intended to show what can be achieved, it is no way intended to by an indication of what can be achieved for ANY configuration.
If you select a combination of sample rate and output frequencies that results in harmonics folding back very close in to the fundamental, you will absolutely get worse than -95.
We stand by the data and plots in the datasheet. They were generated in our lab. It is an honest representation of what the capabilities of the AD9915.
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