A customer has encountered unexpected behavior with the LMH6628 in their product and are in initial investigation stages.
One thought is what might happen to the LMH6628 op amp if the input common mode voltage range is exceeded, as well as a differential input voltage of ~2V. We operate on +5VDC and GND. The input voltages could be anywhere from GND to +5V, definitely not exceeding the supply rails.
I see from the datasheet that the ABS MAX specs for both CM and DM input voltage is V+ to V-, so we are meeting that. I don’t see a problem with DM input levels. I also see the CM input voltage range is specified as +/- 3.7V with +/- 5V supplies. I gather from this the device is guaranteed to meet spec if the input voltage remains at least 1.3V from the supply rails - in our case between 1.3V and 3.7V. I also notice that unlike some other LMH series op amps, there is no statement that output phase reversal will not occur if the input common mode voltage range is exceeded.
So the questions I have:
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Could output phase reversal occur?
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Could it occur if only one of the inputs is outside the CM input range?
Another question is would the PSPICE model include this effect?
