Noise performance analysis

[bageduke]

With comparable parameters, which circuit has better noise performance at Vout? Can someone give me a detail analysis?

Thanks,

 

[yuchi]

I would say Fig B has less noise sources then does Fig A beause Fig A has one more transistor M2 and therefore has more noise source.

However, if M2 acts like a cascode device, the it has less effect on the noise.

 

[bageduke]

But Figure B also has transistor M2. Both have exactly same number of noise source.

 

[tarun_taurus]

I think Circuit B will be better off in terms of noise as it will oppose the cause of the change.