quiz3_2003_soln - I“ Name SoLu flows Rensselaer...

Unformatted text preview: I“ Name SoLu flows Rensselaer Polytechnic Institute Department of Electrical, Computer and Systems Engineering ECSE-ZOSO Spring 2003 Quiz 3 Print your name on every page and show all work to ensure partial credit. Problem 1 (40 points) Problem 2 (30 points) Problem 3 (30 points) Total Name SOL L» 1'! ou§ Problem 1: ' Consider the multistage amplifier shown below. The parameters for the devices and DC bias currents are shown on the diagram. -r LS" V [is k’WIL.= m. nan/V; V = H/ .5)“: T ‘ fix 0 N+ ((4.9— E‘fl {5:400 5 {TALODHH-z C 12.5.0F WI \awvéis a) Determine the mid-frequency voltage gain for the whole amplifier, vo/vs. Note that the DC bias currents are indicated on the diagram. Show your steps clearly to maximize partial credit. I; lMA - S1 351’: W: 7;; 35‘MV - {OH *IV :’ 315K52— s )9 (, éxu'5)(9.ysm'3 -" \-‘1 3: mfi/V Name 50'; 9113 (EMS b) Estimate the lower 3 dB frequency for the multistage amplifier. Again, show your steps clearly to maximize partial credit. CS : C = lid/L” J" =‘°°“I»13>t\6‘3 = 852.1571; ’5‘ ”‘3'“ (”5: ms“ 53M C , CBJOJAF E I? ‘ 6K“ r «:331 :S—CMKEJL 43: LWMS a Jew CC}! CF—ST/‘F ; ‘4 zaoms (6“.- ll<+5k:bl4 “ gm lr‘ lil’ N\ “Mt «We ' c) Assume that you are able to adjust the value of one capacitor to improve (lower) the lower 3 dB frequency. Based on your results for (b), which capacitor value should you change and in what direction to get the most improvement? Cewmm‘i‘4‘fidflmwffl . z Name Jaw; c) Estimate the upper 3 dB frequency for the amplifier. Again, show your steps clearly to max— Fau—Ls. 311', “(1' * CmHquv “TC (“+6 3 a. 33k = ask “3M : ma. om. a— Reel- (1“- ii 34:31 “("KQ‘tM “is r 0+J~MC3¢F)+‘€F = ”We?- ‘23: \®K\\3.BH\\L'~H1 : ‘NkJL ‘ —-J—-— MVMB ‘ckg JTrZ‘rL" Problem 2: Consider the differential amplifier drawn below. 2,5 W =_ m m b) Find the common—mode gain, Ac WWW dd M‘me wak‘lmw widen. - bold m,- “L" - m rfi-rc n+9) )(ms) M, .m, Name EaLuTlaMS 0) Assume that Ad = -40 and Ac = -0.3, find the output voltage when v1.1 = 1.01 +2sin21t6Ot 1.09 + 2 sin21t60t No‘ A4 NM M2 = («ox-.02) + (hams nature“) ”a = 2.885 — ,stgfi'léo-é d) Assume that Rid = 5 k!) and Ric = 100 k9. Find the input cunents, ii] and iiz, when the volt- ages in part (d) are applied. C. — NJ + Nc, + 2L'& 9““)- dl ‘— Red JKL'C. fix“, an“ 5 -4 a? 4. Lo: #3:, { _- In“ M lTréO‘é 9’ Name gm. UEI l N 5 Problem 3: ' The circuit below uses series-shunt feedback. The details of the DC biasing have been omitted and the DC current source can be assumed to be ideal. The feedback network is indicated on the diagram . ‘--—————.__J REE» mi: .451ka 2 a) Evaluate the parameters for the feedback network that are needed to analyze the circuit using feedback analysis. a ”"V' ( 'Sotuzawzm. .4. ”K «A HP 5. 1650 b 4 + V. SOIL, v)- - v; .59.“ .. _ — L‘\a_{ "' = '1 0V ' ‘ b) Draw a schematic for the modified forward amplifier and evaluate its gain, a. vcg "“m o , ‘ A 7 . g}- %M.l‘ ins—:4}! : 00“ “IV 1 mg @4th 2.5K HSK " Re 3 Q> rm- oww —» ‘K H” Q _ - 0 MS ‘ 050 Ian o (77}. i” D: J?— H847. 3/ ¢ $14.11. - ,;_ aw ’ r i am; )SMV 7 Name Mg Ow 1' C‘— AW; U—rEM/as'oulw) — .CHC‘ rm; 4- (/+fi)(}>SD/IIJZ>) " Eur r1w (fififlnsolllm) ; mam. MW 513% .’ CE = —%M1(tk\lq.85k) = ~7a.(. fl» va r11}: prom. In(u.1' 522 3 (E, 75m IQSK) A ,5( L = "i an —- ”ff-fl; w rm + ((50%? Name 5‘de Io c) Evaluate the gain of the feedback amplifier (ie. the closed-loop gain). °~ 6a: A; W... I+Cco>x.o\«) :- d) Find the input resistance of the feedback amplifier as indicated on the diagram. (NHLWJC EB.) 2L 329/». Law SMU-CQ EC; (K4. RC‘I .7 8x35 K‘K Luv-k Mud.) E; = KL‘CHAF) = waft-l so; new)? ' =20? k4; W‘i‘a lk MAI-AM re” 2 éofikfi-Ika .- ...
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