Op-Amp Bandwidth Analysis

How to use this calculator

Most op-amps have a roughly constant gain-bandwidth product (GBW): the product of the open-loop gain and the frequency at which it's measured. The closed-loop bandwidth is approximately f_cl ≈ GBW / |Av_cl|. Enter the GBW (from the datasheet) and the closed-loop gain you're using, and the calculator shows the closed-loop bandwidth and a live GBW trade-off curve.

What it means in a real circuit

For an op-amp with GBW = 1 MHz and a closed-loop gain of 10, the bandwidth is ≈ 100 kHz. Doubling the gain halves the bandwidth — that's the fundamental gain-bandwidth trade-off. This approximation assumes the open-loop response rolls off at −20 dB/decade (single-pole), which is true up to the unity-gain frequency; for very high closed-loop gains or multi-pole op-amps, the real bandwidth can be lower and stability (phase margin) must be checked. Use this to verify an op-amp can handle your signal bandwidth at a given gain, or to pick a higher-GBW part when you need both high gain and wide bandwidth.