Wikipedia: Slew Rate (grime mathematics)

from Slew rate wikipedia:

slew rate effect on a square wave: red= desired output, green= actual output

Definition

The slew rate of an electronic circuit is defined as the maximum rate of change of the output voltage. Slew rate is usually expressed in units of V /µs.

\mathrm{SR} = \max\left(\left|\frac{dv_\mathrm{out}(t)}{dt}\right|\right)

where v_\mathrm{out}(t) is the output produced by the amplifier as a function of time t.

Limitations in slew rate capability can give rise to non linear effects in electronic amplifiers. For a sinusoidal waveform not to be subject to slew rate limitation, the slew rate capability (in volts per second) at all points in an amplifier must satisfy the following condition:

\mathrm{SR} \ge 2\pi f \times V_{\mathrm{pk}},

where f is the operating frequency, and V_{\mathrm{pk}} is the peak amplitude of the waveform.

…Measurement

The slew rate can be measured using a function generator (usually square wave) and oscilloscope. The unit of slew rate is typically V/µs. The slew rate is same for both when feedback is considered or not considered.

Slew rate limiting in amplifiers

There are slight differences between different amplifier designs in how the slewing phenomenon occurs. However, the general principles are the same as in this illustration.

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