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(ELEC304)2009_s_mid_sol_elec304.pdf
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ELEC 304 April 21, 2009 1. Problem 1 ( 40 points) Spring 2009 Howard Luong
For the following CMOS op amp, assume that all the transistors are biased in saturation with the same bias current and the same output resistance ro. Assume that the opamp has a singleAnalog Integrated-Circuit Design and Analysis dominant pole!
a) (12 points) Write down the design equations for the following:
MIDTERM EXAM
i) Bias resistor RB as a function of IB, W/L7, W/L8, VT7, VT8 (3 points)
ii) Low-frequency gain vo/vi (3 points)
iii) -3dB frequency assuming that CC >> CL (3 points)
iv) Unity-gain frequency (3 points)

Your Name: SOLUTION

Student ID: b) (12 points) Given ALL conditions specified in the shaded boxes SIMULTANEOUSLY, fill in ALL the empty entries in the following table indicating how much the parameters would be scaled. For simplicity, assume for this part, all other parameters are constant, and gm2RE >> 1. (To save
This is an opened-book exam. Please write all your answers on the exam booklet provided. time, you can simply fill in the following table directly and submit the exam paper with the exam
Dont redraw the whole schematic. Label on the exam paper and submit together with the exam booklet!)
booklet.

For proper credits, please show your work in details, state and justify clearly any assumption you make. Also, if you cant calculate an answer for any question and you need that particular answer for subsequent calculation, make a reasonable assumption and move on.
Make sure that you have all 2 problems and 5 pages including this cover page. The numbers at the end of each question indicate the maximum possible points. There are approximately 90 minutes for a total of 90 points. Please spend your time accordingly (no more than 1 minute for every point!).
IB (W/L)1 (VGS CVT)1 gm1 vo / vi RE CC -3dB
(i) (4 points) x 2 x 2 x 1 x 2
(ii) (4 points) x 2 x 1 x 1 x 2
(iii) (4 points) x 1 x 2 x 1/4 x 4


All necessary parameters are specified in the problems. If you need any extra information, you must probably have overlooked something, but please feel free to make a good assumption or simply ask!
c) (16 points) Assume that all the transistors have the same W/L and that the parameters for the transistors are: pCox = nCox =100 A/V2, Vtp = -0.5V, Vtn = 0.5V and p = n = 0.1V-1. In addition, VDD = 3V, CC = 20pF. Design the circuit parameters RB, IB, RE, and W/L1, to SIMULTANEOUSLY achieve the following specifications:


Good Luck and Have Fun !!! .
Unity-gain frequency DC Gain VGS-VT VD1 (=Vx, DC) Power Consumption
> 50 MHz > 40 dB >= 0.2V < 2.1V < 10 mW 20pF

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