AD9822: External reference

Document created by analog-archivist Employee on Feb 23, 2016
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Thank you very much for the information. I understand that the converter
range is two times the difference of (CAPT-CAPB). Are there restrictions
on the absolute voltage level of CAPT or CAPB? Well, certainly between 0
and +5.0V, but, for example, must it be centered around 2.5V?


Make sure you disable the internal VREF using the register, and keep your
voltages centered about the CML pin (about 2.5V). A dual op-amp is a common
method to drive the differential reference pins and keep the voltages
symmetrical about CML. You should not exceed the 2V reference level (4V full
scale range), and keep in mind that as you decrease the voltage below 1V (2V
full scale range) you will see increased noise and degraded linearity.