Closed Loop Gain Bandwidth

The band of frequencies over which the gain of the closed loop is called closed-loop gain bandwidth, which is almost constant, to within a certain number of decibels (usually 3 dB).

If the op-amp has been stabilized to operate at unity gain, then the Unity Gain Bandwidth is approximately equal to the Gain Bandwidth Product.

The relation between closed-loop gain bandwidth, GBWP and Noise Gain G_N (G_N =1/β)

BW ~ GBWP / G_N

Now we can calculate the approximate closed-loop gain bandwidth based on GBWP and noise gain.