{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture 12

# Lecture 12 - Lecture 12 OUTLINE Cascode Stage Reading...

This preview shows pages 1–3. Sign up to view the full content.

1 Lecture 12 – Slide 1 EE105, Fall 2013 Prof. Ming C. Wu Lecture 12 § OUTLINE Cascode Stage § Reading: Chapter 9.1 Lecture 12 – Slide 2 EE105, Fall 2013 Prof. Ming C. Wu Ideal Current Source § An ideal current source has infinite output impedance. § How can we increase the output impedance of a BJT that is used as a current source? Equivalent Circuit Circuit Symbol I-V Characteristic + - V I 1 I I V 1 I N I N R

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 Lecture 12 – Slide 3 EE105, Fall 2013 Prof. Ming C. Wu § Recall that emi+er degenera0on boosts the impedance seen looking into the collector. This improves the gain of the CE or CB amplifier. However, headroom is reduced. Boos0ng the Output Impedance R out = 1 + g m R E || r π ( ) ! " # \$ r O + R E || r π E E E V I R = Lecture 12 – Slide 4 EE105, Fall 2013 Prof. Ming C. Wu Cascode Stage § In order to relax the trade-­‐off between output impedance and voltage headroom, we can use a transistor instead of a degenera0on resistor: § V CE for Q 2 can be as low as ~ 0.4V ( soL satura0on ) ( ) 1 2 1 1 1 2 1 1 2 || || )] || ( 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern