If a step input is too fast for an op-amp's slew rate, what happens to the output waveform?

• A. It will overshoot
• B. It will be slew-rate limited, causing distortion or triangular edges
• C. It will saturate
• D. It will be perfectly reproduced

Answer: (B)

Slew rate is the maximum rate at which an op-amp can change its output voltage, defined as dVout/dt. When a step input arrives, the ideal output would jump instantly, but if the step is faster than what the amplifier can handle, the output cannot follow with a sharp edge. Instead, it ramps up or down at the maximum allowed slope, producing a linear, ramped edge. This limited, triangular-shaped transition is the hallmark of slew-rate limiting and represents distortion of the waveform relative to the fast input step.

Other outcomes like overshoot or perfect reproduction aren’t the typical result of a step being faster than the device’s slew rate. Overshoot is more about transient dynamics and timing margins, while perfect reproduction would require an unlimited (infinite) slew rate. Saturation can occur if the required change is extremely large and long enough, but the immediate, defining behavior for a fast step is the slew-rate–limited, ramped edge.