Page 81 - Op Amps Design, Applications, and Troubleshooting

64 AMPLIFIERS

Slew-Rate Limiting Frequency. The highest frequency that can be amplified
without distorting the waveform, because of the slew rate limitation of the op
amp, is given by Equation 2.11.

If it is known for certain that the actual output swing will never be required to
reach its limits, then the lower actual output swing can be used in place of v o(max)
in the above calculation.

Maximum Input Voltage Swing. The maximum input voltage swing is sim-
ply the highest input voltage that can be applied without driving the output past
the saturation point. It is computed in the same manner as that for the inverting
amplifier.

Since we are working with sinusoidal waveforms, we might choose to express
this value as peak, as in Equation (2.13), or RMS, as in Equation (2.14), as shown:

If you attempt to amplify signals larger than 1.425 volts RMS, then the peaks on
the output waveform will be flattened at the output saturation voltage limits.

Output Impedance. You will recall from the analysis of the inverting amplifier
that the effective output impedance decreases sharply from the open-loop value