Op-Amp Slew Rate and Full-Power Bandwidth Calculator
The highest frequency an op-amp can reproduce at a given output amplitude, the slew rate your signal needs, and the largest undistorted swing at your frequency.
Results
The dashed line marks the value you entered.
What this tool does
An op-amp has two separate speed limits. The gain-bandwidth product limits small signals: a 1 MHz part at a gain of 10 gives 100 kHz. The slew rate limits large ones, because a sine of peak V and frequency f changes at up to 2π f V volts per second, and when the output cannot move that fast it turns into a triangle. A 0.5 V/µs amplifier swinging 5 V peak is slew-limited above about 16 kHz — long before its small-signal bandwidth runs out.
Formula
full-power bandwidth f = SR ÷ (2π V_peak) · slew needed = 2π f V_peak · small-signal bandwidth = GBW ÷ gain
Variables
| Symbol | Meaning | Unit |
|---|---|---|
sr | Slew rate of the op-amp | V/µs |
vp | Peak output amplitude you need | V |
gbw | Gain-bandwidth product | MHz |
ga | Closed-loop gain of your circuit | — |
f | Signal frequency | kHz |
FP | Full-power bandwidth (largest frequency at that amplitude) | kHz |
SS | Small-signal bandwidth at that gain | kHz |
US | Usable bandwidth at that amplitude (the lower of the two) | kHz |
NE | Slew rate your signal needs | V/µs |
VM | Largest undistorted peak at your frequency | V |
ST | Does the output keep up? | — |
Worked example
- Slew rate of the op-amp0.5 V/µs
- Peak output amplitude you need5 V
- Gain-bandwidth product1 MHz
- Closed-loop gain of your circuit10
- Signal frequency20 kHz
- Full-power bandwidth (largest frequency at that amplitude)15.92 kHz
- Small-signal bandwidth at that gain100.00 kHz
- Usable bandwidth at that amplitude (the lower of the two)15.92 kHz
- Slew rate your signal needs0.628 V/µs
- Largest undistorted peak at your frequency3.98 V
- Does the output keep up?No — slew-limited: the sine turns into a triangle
Limitations
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
- Coverage and consumption figures vary between products. Take the values from the manufacturer's datasheet for the product you are actually using.