Traditional LDO design, domainant pole 99.99999% result from output cap(Co). in real life design, this is a real capicator, therefore, it is not an ideal cap and will have resistance, it is know as Resr. Because of Resr, there is a zero.
Co master the domainant pole, the zero will cancel the 2nd pole from AMP's output. There is also, a high frequency pole, that is behind UGF.(*but i forgot where it is from, and i am lazy to check this out to u now*)
So, it may be or most liekly that, there is 3 pole, 1 zero in typical LDO.
People nowadays plays LDO at least in the following ways :
1> due feedback loop.
2> break down final stage into smaller piece on PMOS in order to create more pole/zero pairs by feebback control.
3> damping effect control.
4> adding zero in some place btween domainant pole and UGF
all these methods are........playing with maths and then turn it into circuit...
All are the things i know upon now. In fact, if u have time to study LDO papers. u should discover how people playing on LDO. and u must got more more knowledge on circuit design ~
i hope u will draw the same conclusion as me so that there is one more ppl prove i am right or....there is two ppl wrong in the world.....................