In a negative feedback configuration of an operational amplifier, the output voltage can never exceed the supply voltage limits regardless of the input signal levels.

In a negative‑feedback op‑amp, the feedback loop forces the amplifier to drive its output so that the difference between the input terminals is nearly zero, but the device can only supply a voltage that lies between its positive and negative supply rails. Because the output stage is powered by those rails, it physically cannot produce a voltage higher than the positive rail or lower than the negative rail, even if the input tries to push it further. When the input would demand a larger output, the amplifier simply saturates at the nearest rail, and the feedback loop then stops trying to drive the output further. For example, if an op‑amp powered from +15 V and –15 V rails receives a 20 V differential input, the output will clamp at about +15 V (or –15 V) and the feedback will keep the input terminals nearly equal. Thus the output voltage is always bounded by the supply limits, regardless of how large the input signal becomes.