Op-Amp Bandwidth Calculator

An op-amp's usable frequency range shrinks as you increase its gain — the Op-Amp Bandwidth Calculator finds exactly where that cutoff falls for your circuit. Select your amplifier configuration (inverting or non-inverting), enter your R1 and R2 resistor values, unity-gain frequency, and desired voltage gain to calculate the bandwidth (fc). Secondary outputs include noise gain, closed-loop gain, gain-bandwidth product, and a calculated R2 value.

Configuration *

Ω
Ω
Hz
V/V

Results

Bandwidth (fc)

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Noise Gain (Kn)

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Closed-Loop Gain

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Gain-Bandwidth Product

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Calculated R2

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Frequently Asked Questions

What is the difference between inverting and non-inverting op-amp configurations?

Non-inverting amplifiers provide higher bandwidth for the same gain compared to inverting amplifiers. The noise gain for non-inverting is (R1+R2)/R2, while for inverting it's (R1+R2)/R1, affecting the overall bandwidth calculation.

How is the bandwidth of an op-amp calculated?

The bandwidth (fc) is calculated as the unity-gain frequency (fu) divided by the noise gain (Kn): fc = fu / Kn. This represents the -3dB frequency where the gain starts to roll off.

What is gain-bandwidth product and why is it important?

The gain-bandwidth product (GBW) is a constant for a given op-amp, equal to the product of gain and bandwidth at any frequency. It determines the maximum usable frequency for a specific gain requirement.

How do I choose the right resistor values for my op-amp circuit?

Resistor values should be chosen based on your desired gain, input impedance requirements, and noise considerations. Typical values range from 1kΩ to 1MΩ, with lower values providing better noise performance but higher power consumption.

What is noise gain and how does it differ from signal gain?

Noise gain determines the bandwidth of the amplifier and is always positive, regardless of the signal gain. For inverting amplifiers, the signal gain can be negative while the noise gain is always (R1+R2)/R1.

Why does bandwidth decrease as gain increases?

This is due to the constant gain-bandwidth product of op-amps. As you increase the gain, the bandwidth must decrease proportionally to maintain the same GBW product, which is a fundamental limitation of the op-amp's internal compensation.

How much bandwidth does my op-amp need for my application?

The required bandwidth depends on your signal frequency and desired accuracy. As a rule of thumb, the op-amp bandwidth should be at least 10 times higher than the highest signal frequency to maintain good performance.