Lecture 9: Finding zeros by inspection; Source follower: poles and zeros

This lecture derives the transfer function of a source follower. It is noted that there is one pole and one zero. The reason behind the pole location is discussed. Later techniques to detect the existence of zeros is explained. The foolproof way is based on the time-transfer constant technique derived by Prof. Hajimiri in chic.caltech.e...

[@Aadhyacedt]

Nice lecture-At zero frequency does magnitude goes to zero? I think that only true for complex zero however the circuit trick is working well to find zero by shorting the o/p to ground. For example take a system with TF of s+1/s+3. What is the significant of zero at -1 here? Thanks.

[@sscdiitk]

The response to a sinusoidal input does go to zero at the zero frequency, if the system has a purely imaginary zeros +/-jw0.
The notion of complex frequency "s" is an enabler to analyze the stability of LTI systems. Having a zero at s=-1, means that a sinusoidal input at 1rad/s will experience a phase advance of 45deg and the magnitude will be scaled by sqrt(2).

[@devdh8388]

At 4:57 , why Cgd of M2 not conisdered? you are saying only capacitance in M2 is Cdb

[@guhanrajasekar5993]

I think Cgd will occur in parallel with Cdb and so they can be added together as both gate and the bulk of M2 will act as incremental ground.