melvin1109
Newbie
Hello All,
I have a question regarding the charge sheet model of the MOSFET. I am currently reading the book "Systematic Design of Analog CMOS Circuits" by Jespers and Murmann.
I am a bit unsure of the physical phenomenon that causes the behavior shown in the attached graph. The graph was generated by the Authors and provided in a MATLAB file, I screenshot the resulting output of the .m. This is Figure 2.2(page 25) in the book.
My understanding based on the figure and the explanation in the book:
The channel voltage "V" has control on the surface potential "\[\psi\]s" up until the pinch-off voltage which denotes the boundary between strong and weak inversion. Strong Inversion is to the left of the pinch-off and weak inversion is to the right of the pinch-off.
I am having a hard time understanding the underlying reason as to why this is the case.
My Questions:
1. My main question pertains to why can we determine weak vs. strong inversion based on this alone(psi and V)?
2. I know the concept of a threshold voltage is irrelevant when it comes to the CSM(Charge Sheet Model) but how does that have an impact on why we can sweep through strong and weak inversion with a constant gate voltage Vg?
Regards,
Melvin
I have a question regarding the charge sheet model of the MOSFET. I am currently reading the book "Systematic Design of Analog CMOS Circuits" by Jespers and Murmann.
I am a bit unsure of the physical phenomenon that causes the behavior shown in the attached graph. The graph was generated by the Authors and provided in a MATLAB file, I screenshot the resulting output of the .m. This is Figure 2.2(page 25) in the book.
My understanding based on the figure and the explanation in the book:
The channel voltage "V" has control on the surface potential "\[\psi\]s" up until the pinch-off voltage which denotes the boundary between strong and weak inversion. Strong Inversion is to the left of the pinch-off and weak inversion is to the right of the pinch-off.
I am having a hard time understanding the underlying reason as to why this is the case.
My Questions:
1. My main question pertains to why can we determine weak vs. strong inversion based on this alone(psi and V)?
2. I know the concept of a threshold voltage is irrelevant when it comes to the CSM(Charge Sheet Model) but how does that have an impact on why we can sweep through strong and weak inversion with a constant gate voltage Vg?
Regards,
Melvin
