TLV9361: No phase reversal information

Hi Ron,

hmm, but the datasheet says that the common mode input voltage must stay 2V below the positive supply voltage. So the figures aren't valid because the common mode input voltage range is violated? Also, the figures are only showing typicals, not giving any guarantee.

If I had to use such an OPAmp and the datasheet doesn't explicitely tell something about phase reversal, I would mount a voltage divider at the input to prevent the violation of common mode input voltage range. By this phase reversal would be prevented at the same time. That's how we managed things decades ago, way before the introduce of input rail-to-rail OPAmps

Kai

Kai,

The figures are not completely certain because not every data sheet and chart are correct. As you said there is no guarantee or any leverage in compliant if a phase reversal did happen. Thanks for responding because I meant to state this.

There is more than one kind a phase reversal. The oldest and most troublesome kind is like on older TL072 where just one input (within power rails) can cause output to rail regardless of the other input. TLV9361 won't have this kind.

There are two kinds of modern phase reversal. One is when an input goes below ground (negative supply pin); parasitic current can force an output state; few few modern op amps will do this (better parasitic current collection). Almost every older op amp will be affected by this parasitic current. The second kind is when both inputs are out of range (still inside power rails) and the input stage cutoffs. In an open loop (comparator mode) setup, the output may be high or low. In closed loop the output will go high or may go low just enough to get one input (almost always IN-) back into range. Therefore the results are not consistent but way more acceptable than a full phase inversion.

Hi Ron,

thank you for these insightful details.

Kai