I was reading wikipedia page of Gain-Bandwidth Product and got struck at one particular statement.
For devices such as operational amplifiers that are designed to have a simple one-pole frequency response, the gain–bandwidth product is nearly independent of the gain at which it is measured; in such devices the gain–bandwidth product will also be equal to the unity-gain bandwidth of the amplifier (the bandwidth within which the amplifier gain is at least 1).
I am unable to understand why only one-pole frequency response devices can have constant Gain-Bandwidth Product? Why can't a device with two pole have constant gain-bandwidth product? Can someone give me mathematical and intuitive explanation?
In the above picture, after looking at frequency response of an op-amp, it looks like it have two-poles rather than one-pole.
Also, the gain curve (with orange pen) is of op-amp with negative feedback. Does it mean negative feedback just moves the location of poles farther (away from each other) and hence, bandwidth is increased at expense of gain?