Noise in conventional two stage opamp

[eva9scence]

how are noise and miller capacitance are related in two stage opamps? I am given a noise spec and I have to derive the compensation capacitance from noise spec. Kindly let me the relation. I have been looking for that topic but I couldn't find it.

 

[balucyber124]

noise is the general thing in analog so capacitance is used generally to wipe out small noise disturbances this is how it works initially the capacitor gets charged and when the voltage flowing is low in the main o/p it discharges and reduces the off set when main is more then it charges thus reducing the offset in the o/p and noise is reduced.

 

[radius2]

If you know your noise requirement then you should be able to determine the bias current in the amplifier as the two are related (More current -> less noise). This also gives your transconductances gm1 in the first stage. Then depending on your requirement on the gain bandwidth and the phase margin you need, it is possible to determine the compensation capacitor. For 60deg phase margin the second pole should be p2 > 2*GBW (See analog IC-book for example Allen and Hollberg) where GBW = gm1/Cc. gm1 is the transconductance of the first stage and Cc is the compensation capacitor.

 

[eva9scence]

Thank you so much for the help.