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AD9129

Question asked by tneagoe on Jan 15, 2014
Latest reply on Jan 17, 2014 by FPR

Can you confirm that “output compliance range” is the DC
(let’s say instantaneous in case of an AC signal) voltage range the output must
stay in at any moment to preserve proper DAC operation (linearity, saturation,
breaksown and so on)?  If so, since output compliance range is 1.5-2.5V,
it would mean a maximum voltage swing of 600mVpp is available for any signal
output biased at the optimum 1.8V common-mode voltage (see “output stage
configuration” on page 52).   Right?

 

If above “limitation” on voltage swing  is right then
the 50ohms load example on figure 152 would need Ioutfs to be 6mA at maximum to
avoid going out of the compliance range ((1.8-1.5)/50=6mA).  Minimum
Ioutfs value of AD9129 is 9.4mA.  It does not match.  Therefore,
there must be something I misunderstand in all of this.  Can you help me
out with that?

 

In addition, I don’t understand the definition of Ipeak on
page 52.  I would believe Ipeak to be either Ioutfs (DC) or the RMS value
of some AC signal (most probably a sine wave) using Ioutfs=whatever.  That
would mean the peak AC current is .707*Ioutfs.  Either cases don’t match
with the statement “If the AD9119/AD9129 is programmed for an IOUTFS  = 20
mA, its peak ac current is 9.375 mA”.  So, what is Ipeak and how is it
calculated?

 

Thank you for your assistance,

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