I have a circuit that uses an AD9281
If I connect VREF/2 to both inputs I should get code 128 out.
For channel 1 I am getting 128 + 16 and for channel 2 I am getting 128 + 32
VREFB is 1 volt and VREFT is 2.5 volts
I suspect something wrong wit VREFT as…
I got stuck into the various problems with my system.
1/ My op amp circuit was too close to the PIC clock circuit and was picking up 8MHz.
2/ AD9283 required better decoupling.
3/ The /AIN pin is not biased centrally and I had to put an extra resistor…
You're calculations seem to be correct, and are consistant with both the Spec table on Analog Inputs (page 3 ) and the text on page 14.
The common mode range si set by the input design, and departing from it will result in significant…