1 Reply Latest reply on Apr 21, 2014 6:41 PM by user_14586677

    Sigma Delta Non-Linear

    ben.s.

      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?