jdac_18
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I am testing a 10-bit segmented current steering dac, 4-binary, 6-thermometer. I have tested the Static parameters and get an INL of 0.5LSB and DNL 0.4LSB with no filter. Now I am testing the Dynamic parameters, and it seems pretty bad. The initial specs were for the dac to sample at 800Msps up to about 1/2 the nyquist. At 800Msps with a 10Mhz input sine, I can only an SFDR of 33dB. At higher input frequencies the SFDR goes down to below 10dB. I also checked the output on an oscillascope and starting from about 50Mhz the output is not a good sine wave, and by 200 it resembles a pulse. 10Mhz sine has quite a bit of glitch. Below is the screen shot.
Could it be a clock problem? Jitter, crosstalk? Or a design flaw.
Equipment: Agilent PPG Osc voltage generator
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