• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Engineering Input Impedance of a MOSFET circuit

172
6
1. Homework Statement
hdiN9.png

sXeHX.png

(From Razavi's Design of Analog CMOS Integrated Circuits - Chapter 6)

2. Homework Equations


3. The Attempt at a Solution

Not too sure about calculating the input impedance of this. Initially I thought that it would be the series combination of C1 and C2, since we are neglecting Cgs, so
43a4bf8673.png


But after I actually did it on paper, I got something like this,
422d797d3e.png


Usually, I would try and use superposition for this but I don't see how that would work since Vx would dissapear. Honestly, I have no idea what to do now?
 

Attachments

172
6
EDIT: I just realised my mistake. When calculating input/output resistances, all independant sources have to be zeroed just like in Thevenin's Theorem, so that current source there shouldn't be there in my small-signal model.
From that it's just one KCL and job done.
 

rude man

Homework Helper
Insights Author
Gold Member
7,494
657
So what is your answer?
 

Want to reply to this thread?

"Input Impedance of a MOSFET circuit" You must log in or register to reply here.

Related Threads for: Input Impedance of a MOSFET circuit

Replies
4
Views
866
Replies
12
Views
599
Replies
13
Views
621
  • Posted
Replies
15
Views
4K
  • Posted
Replies
2
Views
4K
  • Posted
Replies
15
Views
2K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top