Electrical & Electronics
Op-Amp Bandwidth & Slew Rate Calculator
Estimate op-amp bandwidth, sine-wave slew requirements and amplitude or frequency limits.
Your inputs
Your results
- Estimated small-signal bandwidth
- —
- Noise gain
- —
- Required slew rate
- —
- Slew-limited sine frequency
- —
- Slew-limited maximum amplitude
- —
- Estimated gain reduction
- —
Curve shows the bandwidth model. The dashed fSR line marks the slew limit for the entered amplitude; it is not a distortion simulation.
BW ≈ GBW / NGCheck op-amp bandwidth and sine-wave slew requirements
Compare an amplifier's modeled small-signal bandwidth with the slew rate required for a desired output sine wave. The bandwidth estimate uses a single-pole voltage-feedback approximation and the circuit's noise gain. Slew calculations use output amplitude and frequency independently. The tool does not simulate distortion, verify stability or check input range, output swing, supply voltage or loading for a particular device.
Step by step
- Choose inverting or non-inverting operation and enter signal gain magnitude. Enter a positive magnitude for an inverting gain; non-inverting gain must be at least 1. Supply gain-bandwidth product in MHz and slew rate in V/µs from the relevant device conditions.
- Enter frequency in kHz and the desired output amplitude. Choose Vpk, Vpp or Vrms to describe that amplitude. The amplitude belongs to the output signal, so do not enter the input amplitude unless your circuit has unity signal gain.
- Read bandwidth, required slew rate, slew-limited frequency and gain reduction together. The status identifies which modeled threshold is exceeded. Use the curve to compare frequency with bandwidth, then check the actual device's stability, swing and load requirements separately.
Settings and limits
- Signal gain and noise gain
- For a non-inverting circuit, noise gain equals signal gain. For an inverting circuit, noise gain is 1 + the signal gain magnitude. Estimated bandwidth is GBW divided by noise gain, so equal signal gain magnitudes do not give identical bandwidths in these two topologies.
- Amplitude convention
- For a sine wave, Vpp = 2 × Vpk and Vrms = Vpk / √2. Required slew rate is 2πf × Vpk. Changing the convention reinterprets the entered number; update the number as well when you intend to describe the same physical waveform.
- Modeled limits and response
- Bandwidth is the approximate −3 dB point, rather than a guarantee of flat gain below it. The response curve shows bandwidth-related gain reduction. The dashed slew marker describes the entered amplitude's theoretical threshold; it does not add slew distortion to that curve or certify distortion-free operation.
Worked example
Choose non-inverting gain 10, GBW = 1 MHz, slew rate 0.5 V/µs and output amplitude 1 Vpk. At 10 kHz, bandwidth is 100 kHz, required slew rate is 0.0628319 V/µs and modeled gain reduction is −0.0432137 dB.
| f | SRreq | ΔG | Vpk,max |
|---|---|---|---|
| 10 kHz | 0.0628319 V/µs | −0.0432137 dB | 7.95775 Vpk |
| 100 kHz | 0.628319 V/µs | −3.0103 dB | 0.795775 Vpk |
Increase frequency to 100 kHz without changing amplitude. Required slew becomes 0.628319 V/µs, exceeding the entered slew rate, while the bandwidth model gives −3.0103 dB. The slew-limited frequency for this amplitude is about 79.5775 kHz. These are separate constraints; reducing output amplitude improves the slew limit without changing bandwidth.
Questions and troubleshooting
Why does inverting gain 10 show a lower bandwidth?
Its noise gain is 11, so the same 1 MHz GBW gives approximately 90.9091 kHz bandwidth. The minus sign of signal gain represents inversion; it does not make noise gain negative. Enter the gain magnitude in the field.
Does the maximum amplitude result check supply-rail clipping?
It checks only the entered slew rate at the entered frequency, expressed in your selected amplitude convention. Output swing, load current and input common-mode limits are outside this model. A slew-compatible amplitude may still be impossible for the actual amplifier.
Why can the status say within limits while gain has fallen?
The status changes only after frequency exceeds bandwidth or required slew exceeds the entered rate. Gain rolls off continuously before that point. At exactly the modeled bandwidth, reduction is already about −3 dB; judge acceptable flatness and operating margin from your application requirements.