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https://designers-guide.org/forum/YaBB.pl Measurements >> Other Measurements >> Dynamic dac measurements https://designers-guide.org/forum/YaBB.pl?num=1240484992 Message started by jdac_18 on Apr 23rd, 2009, 4:09am |
Title: Dynamic dac measurements Post by jdac_18 on Apr 23rd, 2009, 4:09am 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 |
Title: Re: Dynamic dac measurements Post by ywguo on Jun 7th, 2009, 9:42pm It looks like the design has some flaw. But what do you use to measure the dynamic performance? |
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