About

This tool utilizes the relationship between slew rate, frequency, and voltage amplitude of a sinewave to provide any of the following:

1. An op-amp or other amplifier's minimum slew rate needed to provide a given output voltage at a given frequency.
2. Maximum frequency supported by an amplifier with a given slew rate at a given signal voltage amplitude.
3. Maximum undistorted output voltage that an amplifier can produce, given the amplifier's slew rate and the signal's output voltage amplitude.

This calculator utilizes the following formula to solve for each parameter:

$$S_{min} = 2 \pi f A$$

where: $S_{min}$ is minimum required slew rate in V/s for a sinewave with an with a peak voltage $A$ volts and a frequency $f$ Hz.

Instructions

To get started, fill in any two fields. The parameter in the remaining field will be calculated and appear automatically. The scale of the voltage and frequency inputs can be selected on the right of each field.

For example, to calculate the minimum slew rate required for a sine wave with a voltage amplitude of 1.0V peak, and a frequency of 10MHz, enter these values and scales in their respective calculator fields. The resulting minimum slew rate of 62.8 V/us will appear in the slew rate field.

Theory

The rate at which an op-amps's output can change is limited by factors such its internal compensation and limited internal drive current. This rate is specified as slew rate or slewing rate. It is important factor to consider because slew rate limits can lead to severe signal distortion.

An op-amp's slew rate can vary substantially from one part to another. For instance, the MCP6004,a low supply current op-amp, has a typical slew rate of 0.6 V/us. Whereas, the high speed TLV3542 op-amp's slew rate is 150 V/us. The table below provides slew rates for some common parts.

References

1. Horowitz, P., & Hill, W. (2015). The Art of Electronics (3rd ed.). Cambridge University Press. (See especially section 4.4k for discussion of slew rate.)