110b-final-2007

110b-final-2007 - A3 1 30 pts Consider the oscillator shown...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

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

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

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

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

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

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

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

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

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

View Full DocumentRight Arrow Icon
Background image of page 10
Background image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: A3 1 30 pts Consider the oscillator shown below and assume that the operational amplifier is ideal (which means that it has infinite bandwidth). The transfer function H( f), which is vp/vo, is also shown below. 101 102 103 104 105 106 107 108 109 101010111012 o 1 f - VG+ -20v‘ _J—- _J—w M‘_—-_ e 4o 16 Magnitude _60 V. ,, ,, R1 R2 ((113) 80 i W 9 WW I -100 v,, _ —120r V0 270 v + 130 P 90 Phase 0 H(f) (Degrees) ~90 -180 -270 5 pts (21) At what frequency is it possible for this circuit to oscillate? Ignore the block labeled G on the schematic for this part. (only your answer will be graded) 7f \ a ‘H ) CXA M B :2 Q : M H D ‘% 73 to M H & 10 pts (b) What is the minimum value of R2 necessary for oscillations to occur if R1 is IkQ? Ignore the block labeled G on the schematic for this part. Make it clear what you are doing or you will not receive full credit. (more room is available on the next page if you need it) [win]: 7‘; a Ammo $9 44114} 4-445" imp Sada will be 1. A = H gem => tag-aer- W»- Q‘LMM 7’ £><AMI3 Maw-l— -_—.5 {2 .29?er lac: A4 5 pts (0) What will the frequency of oscillation be if the op amp contributes -90° of phase to the loop? Ignore the blockvlabeled G on the schematic for this part. (only your answer will be graded) éxA M \3 A a 100 KHz» \MHg 10 pts (d) What will be the peak magnitude of the oscillation at v0 if the block labeled G in the schematic has the transfer characteristic shown below? Use the value you found for R2 in part (b). Make it clear what you are doing or you will not receive fullcredit. iG “ _ Qz KVL- "Us w (1+ E731)” Kai 2n. 1 ‘39. _2V Pl l2; VG Ag ’1) z i t 1351,1212}??me golds-[<1 ‘l'o-l-fcm ate/loll"; 82 2 1+ Ea EL U0 < ‘2“ =<L+ El, 1) (22. We, (a lzmi‘l‘s 4b +ZV) Se 00 FE) lqu'ltDQ 4'73 R <l+ Til-2' :_ Lg...2_ "' QRMB _}__ (Heal : gvgb \/ 15 pts A5 30 pts / Consider the g RC negative feedback RS CW Rm H—KQZ amplifier shown. W Q‘ Almost everyonevs ’— used a circuit :5 $223 :: CE similar to this on T T R com the project and it W o V0 was the circuit Rx shown in the R” g RL solution. ? T (3) Draw the small-signal midband AC equivalent circuit using the appropriate unilateral two-port model for the feedback network (circle the feedback network on the schematic above). Use R; = RS + Rm and R2 = RL + Ram in your circuit and call v; the voltage across R2. Consider v; to be the output variable that is fed back. Give equations for the elements in the two—port model of the feedback network in terms of the components shown on the schematic (you do not need to derive the equations). A6 15 pts (b) Assume that solving for the DC bias point of this circuit reveals: V31 = 1.7 V, V52 = 1.8 V and V32 = 2.5 V, with Rf: 2 k9, R152 = 200 Q, Rout = 50 Q and RL = 50 Q. Derive a value for vomin. Make, state and check the validity of any reasonable assumptions you make (I do not expect an exact answer). I do want a number, but you must show your equations. Make it clear what you are doing or you will not receive full credit. 7\=-\ Wm“ M beamed. be a. Morale?) or QL wing 51:9 1) E? &L éakvl‘aitst ( ignsre, Lowe/1+ 7m, VEL? UE,+V¢£5AT’VBE '7- 11"73—5' Then ) vomihl :- @fisz:Vl—- Via“) 1 avg—I‘YZ- Q;- L 2 v z) 3:? Q2, Lois 0539'- («aga‘m Tamra. Lorre/ct in Qiéd ‘ I 7} M; Z 2"— ' l L l o n - r. QEZ "F Lgv av REL+EOG++ EL)( 3 pts 3 pts 3 pts 3 pts 3 pts 5 pts A7 20 pts Consider a negative feedback amplifier with a forward amplifier described by , 106 auw)‘ 1+2 1+ -2 1+-2 110 1104 1106 and a feedback network described by b (jw) = 0.1 . (a) Draw the Bode magnitude and phase plots for a(ja)) on the axes on the following page. Also draw the magnitude of 1/ b ( jw) on the same plot. (b) What is (0180 ? Give the value here and show it on your plot. ; I EXAMS; '0 M504 103 {WI/<2, (c) What is mu ? Give the value here and show it on your plot. 13‘ axfim Fri F: to “ML/<3 52x16” rad/s (d) What is the gain margin, GM? Give the value here and show it on your plot. 0 aa a” ‘3’ “2.048 (e) What is the phase margin, PM? Give the value here and show it on your plot. 9 O EJAM. B -2,2_.9'° (f) If you added a new dominate pole to this amplifier, what would you need to set the pole frequency to in order to achieve a 45° PM? Give the value here and show how you obtained it on your plot. Degrees 0 -45 ~90 -l35 -180 -225 -270 10-3 .‘fiiifku&bck4“ ‘ t 10-2 10-1 100 11 102 103 104 105 06 107 108 co ‘L 20 0 , 10-3 10-2 10-1 100 101 102 103 > 1.4 105 106 107 108 O W W— -45 I _90_ _ 1 w -135 Degrees -18O —225 ] -270 v —— —v —~ 2‘ A9 4 15 pts Consider the R—2R ladder shown below. You may use the space provided to work out your answers to this problem, but you do NOT NEED TO SHQW YQUR WORK because only your final answers will graded. Be sure to put your final answers in the boxes provided! Assume that VB 2 16 V, R z 8 k9, and 2R=16k£2. r VB :zzu 35¢ 5mm E V3 R V4 21? + iv» W» W» W» w» i 212%»? 2R 5 pts (a) What is V3 (I want a NUMBER)? Put your answer in the box provided to the right. V3 ' \LL. 1 ‘3; w. Ye. L Li if 2 \/ ixA M 13 Va 1 o. 2,\/ 5 pts (b) What is [4(1 want a NUMBER)? Put your answer in the box provided to the right. T : “TL—i : A10 5 pts (c) Briefly explain what the main advantage of an R—ZR ladder is when compared to using a binary-weighted array of resistors. VOA.“ Ck [0;an ’m€;6LCK‘Ccl. awma 1 ‘HAC [$665+ Pasis‘VSF‘ "3 L”*~Hmeg burger +\Aam. ‘H/‘c émlies-i— C‘pol‘ ID 932‘), 1+ Y$ udfl Mari) of‘ impogskkj +o Ma+crbxl Pagfg-Lersb (Aggy! cwoo \4 avg,“ 43oF Meddfrfifi» Vow/.ch 94: N- EW. Wi4iamj 1+ “$4445 cg \ e, W 4° 1% 510+ (‘flfiiEA-Mg @3444. «gggugfltq a Large—w $?T‘&&CL FA Valuag ava 444.6, wN‘cn-F dragon 9mm H46. rewcdcma cJ/wwx tag ) wLxx‘cJ/x 14M! Wmafl 'L‘LtCL V€VQ€J€'HQ&« V69 AA (2le [dollar Clflé‘ifi may? WC, a [44%; g I 1 f“ \ ! 3 _ 1062 "WE: ‘59 .me 5P?“ (A, VQMJCE“: aw 53¢? a. F" d All 5 15 pts Consider the successive approximation analog-to—digital converter shown below and assume that a standard binary search is used. The table below the figure shows the operation of the converter one clock cycle at a time as it performs a conversion on an input voltage VI = 2.5 V, with VFS = 8 V for the three-bit DAC. You are to fill in the six missing values in the table (VCOMP is either High or Low). You may use the space provided to work out your answers to this problem, but you do NOT NEED .TO SHOW YOUR WORK because only your final answers will graded. Put your final answers IN THE TABLE PROVIDED. Successive Approximation Register OUT A12 10 pts Consider the amplifier circuit shown below and assume that VCC = 5 V. Find the values of all of the resistors so that the following bias point is achieved: Only your final answers will be graded and you may safely ignore base currents. PUT YOUR ANSWERS IN THE BOXES PROVIDED. VCC 1" Ear—é,ka ngéAKJL $9558ng ...
View Full Document

This note was uploaded on 06/28/2008 for the course EEC 110B taught by Professor Spencer during the Spring '08 term at UC Davis.

Page1 / 11

110b-final-2007 - A3 1 30 pts Consider the oscillator shown...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online