Currently using the AD7711, however the ADC can only measure between 2.5 and 5.00V. Is this normal operation for this A/D? For instance, after booting up the device, and doing the calibration, the A/D only fluctuates between 2.5-5.0V. The Vref use is 5.00V. I might be doing the calibration steps incorrectly, but I believe I am not.