Op-Amp Slew Rate Calculator
Calculate required op-amp slew rate for high-frequency signals, transient response, and distortion analysis.
Slew Rate Formulas
Sine Wave: SR_required = 2π × f × V_peak
Step Response: SR_required = V_step / t_rise
Full-Power Bandwidth: FPBW = SR / (2π × V_peak)
Settling Time: Dominated by slew rate for large steps; bandwidth for small-signal final ripple.
Op-Amp Slew Rate Comparison
| Op-Amp Type | Typical SR (V/µs) | GBW | Application |
|---|---|---|---|
| TL072 (Jfet) | 13 | 4 MHz | Audio, general |
| LM358 (Bipolar) | 0.5 | 1 MHz | Low-power, slow |
| OPA2134 (Audio) | 20 | 8 MHz | High-quality audio |
| OPA2277 (Precision) | 4.5 | 3 MHz | Instrumentation |
| CLC7440 (Rail-Rail, Fast) | 6000 | 500 MHz | High-speed video, RF |
Frequently Asked Questions
What is slew rate?
Slew rate is the maximum rate at which an op-amp output voltage can change, measured in volts per microsecond (V/µs). Limited by the output stage design and compensation capacitor. Example: 1 V/µs means output can rise/fall at most 1 V per 1 microsecond. Typical op-amps: 0.5–1000 V/µs.
When does slew rate limit matter?
When signal requires faster dV/dt than op-amp can deliver. Example: 10 Vpp sine at 100 kHz requires 6.3 V/µs; a 1 V/µs op-amp cannot follow, output clips at slope limit, causing distortion. High-frequency audio, video, and high-speed analog all need fast slew rates.
How do I calculate required slew rate?
For sinusoid: SR_required = 2π × f × Vpeak. Example: 1 Vpp (0.5 V peak) at 1 MHz requires SR = 2π × 1e6 × 0.5 ≈ 3.14 V/µs. For square wave: SR_required = Vpeak / rise_time. Always add margin; design for 2–3× calculated minimum.
What is slew rate-induced distortion?
If output must change faster than slew rate allows, output voltage lags input. This manifests as clipping/flattening of signal peaks, harmonic distortion, and non-linear behavior. THD (Total Harmonic Distortion) increases significantly when slew rate is exceeded.
How does gain affect required slew rate?
For same frequency and peak voltage, slew rate requirement is independent of gain. However, in feedback circuits, the loop bandwidth interacts: higher closed-loop gain reduces bandwidth, reducing required slew rate. Low-gain high-bandwidth designs need the fastest op-amps.
What is bandwidth (GBW) vs. slew rate?
GBW (gain-bandwidth product, MHz) is AC frequency response. Slew rate (V/µs) is DC transient response. Both matter: GBW limits high-frequency sine waves; slew rate limits fast edges. A fast op-amp must have both high GBW and high slew rate. Trade-off: some designs sacrifice one for the other.
What is the full-power bandwidth (FPBW)?
FPBW is the maximum frequency at which an op-amp can output maximum voltage swing (±Vsat) without slew rate limiting: FPBW = SR / (2π × Vpeak). Example: 10 V/µs op-amp with ±5 V output → FPBW ≈ 318 kHz. Above FPBW, output amplitude shrinks due to slew limiting.
Can I increase slew rate?
Not after purchasing the op-amp (it's a fixed device parameter). To achieve higher slew rate: (1) Choose faster op-amp (higher SR rating), (2) Use current-feedback op-amp instead of voltage-feedback (often faster), (3) Reduce closed-loop gain (higher bandwidth = faster SR capability), (4) Reduce load capacitance.
What is settling time?
Settling time is how long output takes to reach final value and stay within a tolerance band after input changes. Slew rate limits initial transient; bandwidth limits final ripple. Fast slew rate and high bandwidth both reduce settling time.
How do I choose an op-amp for high-speed applications?
Check: (1) Slew rate ≥ 2–3× calculated minimum, (2) Gain-bandwidth product (GBW) ≥ 10× signal bandwidth, (3) Input impedance suitable for source, (4) Supply voltage matches design, (5) Power dissipation acceptable for thermal design.
What happens if slew rate is too low?
Output cannot keep up with input. Fast edges become slopes (rounding/distortion). Sine waves flatten at peaks. Squarewave rising edge slows. Overall THD increases, SNR degrades. System may oscillate or become unstable if feedback tries to correct the lag.
Is slew rate limiting audible?
Yes. In audio, slew rate limiting manifests as high-frequency distortion (mostly upper harmonics), loss of transient clarity, and muffled treble. A 1 V/µs op-amp is marginal for high-quality audio; 10+ V/µs is typical for modern audio designs.