How does an op amp overvoltage condition occur?

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How does an op amp overvoltage condition occur? [Copy link]

     An overvoltage condition can be caused by many different situations. Consider a system where a remote sensor is located in the field—such as the flow of liquids within a refinery—and sends the signal through a cable to data acquisition electronics at another physical location. The first stage in the data acquisition electronics signal path is typically an op amp configured as a buffer or gain amplifier. The input of this op amp is exposed to the environment and can be affected by an overvoltage event—such as a short circuit caused by a damaged cable or a misconnection of the cable to the data acquisition electronics. Similarly, an overvoltage condition can occur when the input signal (usually within the amplifier input voltage range) suddenly receives an external stimulus that causes a transient spike that exceeds the op amp's supply voltage. A third situation that can cause an input overvoltage condition comes from the power-up timing of the op amp and other components in the signal path. For example, if the signal source (such as a sensor) is powered up before the op amp, the signal source can output a voltage before the op amp supply pin is powered up. This can cause an overvoltage condition, potentially forcing excessive current through the op amp input and to ground (the unpowered supply pin).