# Gain-Bandwidth product question

1. Aug 21, 2009

### bitrex

If I have an op-amp with say, a hypothetical bandwidth of 1 MHz, and I use it in a configuration where I have a gain of 10, I know that I will only have unity gain at an input frequency of 100kHz. What I am wondering is how I go about calculating what the effective cutoff frequency is, i.e. where the gain is down -3dB? Thanks!

2. Aug 21, 2009

### uart

No that's incorrect. So long as the other poles (apart from the dominant pole that sets the 1MHz GBWP) are above 100kHz then 100Khz will indeed be a very good approximation to the actual -3dB frequency.