Enter the voltage and the time at 90% and 10% signal into the calculator to determine the slew rate.

Slew Rate Formula

The following formula is used to calculate a slew rate: 

SR = (Vout(P90) - Vout (10P)/(t(90P) - t(10P)
  • Where SR is the slew rate (V/s)(V/us)
  • Vout is the voltage output at 90% and 10% respectively
  • t(90P)-t(10P) is the change in time it took to go from 90% to 10% signal

Slew Rate Definition

A slew rate is defined as the maximum rate of change of an op amp’s output voltage from a signal step of 90%-10%.

Example Problem

How to calculate slew rate?

First, determine the output voltage at 90% signal. For this example, the voltage is found to be 10 volts at 90% signal.

Next, determine the output voltage at 10% signal. For this example, the output voltage at 10% signal is 2 volts.

Next, determine the change in the time it took to go from 90%-10% signal. For this problem, the total time is 10 microseconds (20us-10us).

Finally, calculate the slew rate using the formula above.

SR = (Vout(90%) – Vout (10%)/(t(90%) – t(10%)

= (10-2) / (20-10)

= .8 V/us.

slew rate calculator