1 Reply Latest reply on Apr 21, 2014 6:41 PM by DaKn_263916

    Sigma Delta Non-Linear


      I am having some issues with non-linear and inconsistent readings off the Sigma Delta converter.


      My circuit uses a resistor ladder to attenuate a high DC voltage. That is buffered with an INA217 amplifier. The readings off the amplfier measure in a near linear fashion.


      I am having a problem with the converter. It always reads a few milliviolts below what my meter reads. This variation changes with different voltage readings, especially over a large range.


      The amplifier circuit is pretty linear, so it is safe to say the problem is the converter.


      I read about a similar problem on another thread regarding analog routing and the voltage reference. I have the converter set:


      Range 0-1.024V


      Internal 1.024V reference.


      16 bits at 48ksps.


      What is going on?