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ADE7880 input overvoltage behavior

Question asked by MHS on Dec 10, 2014
Latest reply on Jan 6, 2015 by dlath

I have been using the ADE7880 and it has been working fine with the exception of its behavior when the input goes above about 0.65V. At this point if you look at the raw voltage and current data you start to see notches in the waveforms which increase as the input voltage increases above this point. The notches are severe enough that the RMS voltage starts to go down and at a somewhat higher voltage the zero crossing detector is affected. If you use the programmable gain then the voltage input at which this occurs is 0.65 divided by pga setting (i.e. if the pga is set to 2 the distortion would occur when you go above 0.325 volts). This would make is almost impossible to solve the issue by clamping the voltage if you use the programmable gain. I have used the ADE7758 and it did not have this behavior. It clamped at it maximum output as you would expect. Is this the expected behavior of this part? Do the other parts in this family also have this behavior?