Op-Amp Slew Rate Calculator
Find how fast an op-amp output can change: SR = ΔVout / Δt.
Inputs
Drag the handle (or focus it and press ↑/↓) to reorder. Scientific notation such as 2.5e-6 is accepted. Use a negative ΔVout for a falling edge.
Results
Enter values and press Calculate. Your answer will appear here.
Output voltage vs. time
The solid line is the slew-limited output; its slope is SR. The dashed line is an ideal instant step.
What is being calculated
Common examples
| ΔVout | Δt | SR |
|---|
Typical datasheet slew rates
| Op-amp | Typical SR |
|---|---|
| LM358 | ≈ 0.3 V/µs |
| LM741 | ≈ 0.5 V/µs |
| NE5532 | ≈ 9 V/µs |
| TL081 | ≈ 13 V/µs |
| OPA134 | ≈ 20 V/µs |
Approximate typical values; always confirm against the manufacturer's current datasheet.
Unit conversions
| Slew rate | Equivalent | Time | Equivalent |
|---|---|---|---|
| 1 V/µs | 1,000,000 V/s | 1 ms | 10⁻³ s |
| 1 V/µs | 1,000 V/ms | 1 µs | 10⁻⁶ s |
| 1 V/µs | 0.001 V/ns | 1 ns | 10⁻⁹ s |
| 1 V/ns | 1,000 V/µs | 1 ps | 10⁻¹² s |
Voltage: 1 kV = 1,000 V; 1 mV = 10⁻³ V; 1 µV = 10⁻⁶ V.
Formula
- SR: slew rate (V/s, usually quoted in V/µs)
- ΔVout = V_end − V_start: change in output voltage
- Δt: time taken for that change
Example: a 10 V change in 20 µs gives SR = 10 V ÷ 20 µs = 0.5 V/µs.
Advanced checks. For a sine wave of peak amplitude Vp and frequency f, the slew rate needed to avoid distortion is SRreq = 2π·f·Vp. The full-power bandwidth is fmax = SR / (2π·Vp). Example: SR = 0.5 V/µs and Vp = 10 V give fmax = 500,000 ÷ (2π·10) ≈ 7.96 kHz.
For a slewing measurement, use the output swing between your two measurement points, and use the same swing and time for both. Many datasheets measure between 10 % and 90 % of the step.
References
- Wikipedia, Slew rate: definition and the sine-wave limit
- Texas Instruments, TL081 product page: example datasheet slew-rate specification
- NIST SP 811, Guide for the Use of the SI: unit prefixes
How to Use This Tool
- Enter the output voltage change ΔVout and pick its unit.
- Enter the time Δt it took and pick its unit.
- In Advanced, enter start and end voltages, a different output unit, or a peak amplitude and frequency to test a sine wave.
- Click Calculate.
- Read SR in the highlighted result and check the output waveform.
What This Tool Offers
- Basic and Advanced modes on one calculation engine
- Voltage, time and slew-rate unit conversion
- Rising and falling edge support
- Required slew rate and full-power bandwidth for sine waves (Advanced)
- Output waveform chart and labelled op-amp diagram
- Reorderable inputs and a mobile-friendly layout
Variables
| Symbol | Quantity | Unit |
|---|---|---|
| SR | Slew rate | V/µs |
| ΔV_out | Change in output voltage | V |
| Δt | Change in time | µs |
What it means
The slew rate (SR) of an operational amplifier is the maximum rate of change of the output voltage, defined as SR = ΔV_out/Δt, typically measured in V/µs. It is limited by the internal compensation capacitor and the available current. If the input signal demands a faster output change than the slew rate, distortion occurs (e.g., triangular wave output for a square wave input). Slew rate determines the large‑signal bandwidth and is a key specification for high‑frequency applications. Example: An op‑amp with SR=0.5V/µs can change its output by 0.5V in 1µs. To produce a 10V peak‑to‑peak sine wave at a frequency f, the required slew rate is π·V_pp·f. If f=100kHz and V_pp=10V, the required SR = π*10*100k = 3.14 V/µs, which exceeds 0.5V/µs, causing distortion.
Worked example
Op‑Amp Slew Rate – Practical Example
Real‑World| Parameter | Value |
|---|---|
| ΔVout | 5 V |
| Δt | 1 µs |
| Formula | SR = ΔVout / Δt |
Common mistakes
Watch unit consistency and the assumptions behind the formula; misapplying it outside its valid conditions is the most frequent error.Applications
Op‑amp slew rate SR = ΔV_out/Δt is the maximum rate of change of the output voltage. It limits the full‑power bandwidth and can cause distortion if exceeded. Engineers use it to select op‑amps for high‑speed applications, to estimate distortion, and to design circuits with adequate bandwidth. Slew rate is a key parameter for audio, video, and high‑speed signal processing.
- High‑speed amplifier selection and design
- Audio and video signal processing
- Pulse and waveform generation circuits
- Data acquisition and ADC driver design
- Educational understanding of op‑amp limitations
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