Slew Rate Calculator

Slew Rate Calculator:

Enter the values of Output Voltage at V_out(V)90%, Output Voltage at V_out(V)10%, Time at t_(µs)90%, and Time at t_(µs)10% to determine the value of Slew Rate, SR_(V/µs).

Enter Output Voltage at 90%:		V
Enter Output Voltage at 10%:		V
Enter Time at 90%:		µs
Enter Time at 10%:		µs
Result -Slew Rate:		V/µs

Slew Rate:

Slew Rate (SR) is defined as the maximum rate of change of the output voltage per unit time in an electronic circuit, especially in operational amplifiers (op-amps).It measures the ability of an amplifier to react to fast variations in the input signal.

The unit of slew rate is volts per microsecond (V/µs).A higher slew rate means the amplifier can handle faster-changing signals without distortion.This parameter becomes critical in high-speed or high-frequency applications like audio and communication systems.

Slew rate limitations can lead to signal distortion, especially in signals with high-frequency content.In op-amps, the slew rate is typically limited by internal compensation capacitors and current-limiting circuits.

If the input signal changes faster than the slew rate, the output signal will become distorted or “slewed.”Slew rate is not constant; it depends on the amplifier design and internal circuitry.

Manufacturers provide typical slew rate values in datasheets for electronic components.It is tested under specific conditions, usually measured between 10% and 90% of the voltage swing.The standard test uses a step input and measures the output voltage rise or fall over time.

This test helps in comparing amplifiers for speed-critical applications.
Slew rate is crucial in analog signal processing and affects performance in filters and DACs.

Slew Rate, SR_(V/µs) in volts per microsecond equals Output Voltage at 90 percent, V_out(V)(90%) in volts minus Output Voltage at 10 percent, V_out(V)(10%) in volts divided by Time at 90 percent, t_(µs)(90%) in microseconds minus Time at 10 percent, t_(µs)(10%) in microseconds.

Slew Rate, SR_(V/µs)= (V_out(V)(90%) – V_out(V)(10%)) / (t_(µs)(90%) – t_(µs)(10%))

SR_(V/µs)= slew rate in volts per micro seconds, V/µs.

V_out(V)(90%) = output voltage at 90% in volts, V.

V_out(V)(10%) = output voltage at 10% in volts, V.

t_(µs)(90%) = time at 90% in micro seconds, µs.

t_(µs)(10%) = time at 10% in micro seconds, µs.

Slew Rate Calculation:

1. An op-amp’s output voltage increases from 1V (10%) to 9V (90%) in 2 µs (from 1 µs to 3 µs). Calculate the slew rate.

Given: V_out(V)(90%) = 9V, V_out(V)(10%) = 1V, t_(µs)(90%) = 3 µs, t_(µs)(10%) = 1 µs.

Slew Rate, SR_(V/µs)= (V_out(V)(90%) – V_out(V)(10%)) / (t_(µs)(90%) – t_(µs)(10%))

SR_(V/µs)= (9 – 1) / (3 – 1)

SR_(V/µs)= 8 / 2

SR_(V/µs)= 4V/µs.

2. An amplifier has a slew rate of 2 V/µs. The output voltage increases from 2V to 8V starting at t10%= 4 µst10%​=4µs. Find the time at 90% output,t90%​.

 

Given: V_out(V)(90%) = 8V, V_out(V)(10%) = 2V, SR_(V/µs)= 2V/µs, t_(µs)(10%) = 4 µs.

Slew Rate, SR_(V/µs)= (V_out(V)(90%) – V_out(V)(10%)) / (t_(µs)(90%) – t_(µs)(10%))

2 = (8 – 2) / t_(µs)(90%) – 4

2 = 6 / t_(µs)(90%) – 4

t_(µs)(90%) – 4 = 6 / 2

t_(µs)(90%) – 4 = 3

t_(µs)(90%) = 7µs.