Diffusivity - Microelectronic Devices and Circuits - Exam, Exams of Microeconomics

Download Diffusivity - Microelectronic Devices and Circuits - Exam and more Exams Microeconomics in PDF only on Docsity! Microelectronic Devices and Circuits- EECS105 Second Midterm Exam Wednesday, November 17, 1999 Costas J. Spanos Univerisity of California at Berkeley College of Engineering Department of Electrical Engineering and Computer Science Your Name: Your Signature: 1. Print and sign your name on this page before you start. 2. You are allowed two 8.5"x11" handwritten sheets with formulas. No books or notes! 3. Do everything on this exam, and make your methods as clear as possible Problem 1 _______/30 Problem 2 _______/35 Problem 3 _______/35 Total ______/100 Problem #1 of 3 Answer each question briefly and clearly. (30 points) Explain briefly why BJT performance depends so much on the diffusivity of minority carriers (6pts) How does the small signal output resistance of a BJT depend on its size (emitter-to-base junction area), when VBE is held constant? (6pts) EECS105 MT2, Fall '99 1 Why is it desirable to have VBs = 0V in MOS Common Gate applications? (6pts) What happens to the overall (loaded) |Av| when Ic increases in a CE amplifier? (Assume that RL is initially equal to ro, Rs << rpi and roc = infinity) (6pts) How many poles and how many zeros does this circuit have? What is its function, assuming that R1C1 << R2C2? (6pts) Problem #2 of 3 (35 points) For each of the following questions, make sure that you show the expressions before you plug in the specific values. A correct expression is worth 70% of the credit, even if the numerical calculation is incorrect! You are given the following nmos common drain amplifier. EECS105 MT2, Fall '99 2