Bhupendra
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Hi Mahavir,
I guess it depends on application. If the D/A is used in a low frequency application (like trimming) where monotonicity is all that we care about probably the dynamic performance are not as important.
But for applications where the input bandwidth is defined and you are clocking at a high rate (for example video , SD=6KHz, HD=30KHz) in that case the dynamic performance is what you need to report.
For instance if the D/A is a current steering type then the linearity would be a function of the output impedance which is a function of frequency. The output impedance would be low at high frequency (due to cascode poles) and hence the SFDR would go down.
Similarly when one clocks at high frequencies effects like glitch, charge injection (through switches) and feedthrough come into play and distort the output limiting the dynamic performance.
In all such cases one has to report the SFDR at frequencies of interest (usually the highest frequency in the band).
In some applications a two tone test is also recommended to check for any fold back component in the band.
I hope this helps.
Regards, Bhupendra
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