Diodes - Introduction to Microelectronic Circuits - Solved Exam, Exams of Microelectronic Circuits

Download Diodes - Introduction to Microelectronic Circuits - Solved Exam and more Exams Microelectronic Circuits in PDF only on Docsity! UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering Professor Oldham and Computer Sciences EECS 40 — MIDTERM #2 Name: Last, First Guidelines: 10 November 1999 1, Closed book and notes except 1 page of formulas. ‘You may use a calculator. Do not unstaple the exam. yo YN exam. You can remove these from the rest of the exam if you wish. Points Your Problem Possible Score 1 20 2 20 3 20 4 20 5 20 Total 100 Fall 1999 Student ID: TA: QO Kusuma O Chang Show all your work and reasoning on the exam in order to receive full or partial credit. This exam contains 12 pages plus the cover page and 2 sheets of scratch paper included at the end of the Uses nA noua I  Problem (20 points) What is the value of the unknown node: voltage in each of the following circuits? Assume diodes are. perfect rec- tifiers. (a) w—Dp Kf opts MEF wee P >t = 100K I Vy = IOV 1 ° ww | T* o 100K Vy = 12 © apts Vz= OV @) TK py apts 100K. Av s/ : . ? Van = TI (e) <7 wy. eprs (f) Accross-section for a CMOS chip is shown on the facing page. Some node voltages are indicated. Please tell us what the values are for the node voltages atnodes U, W, R, S. & ; pts Vy = ___5V ¥ If. Ue =6V ond Va =5V wl | de Depts Vy = OV o pts each © Qpts Vr = BY __ % TR Ve =OV ond Vas OV pts Vs = OV ___ apts fee Vi 4 TD Va = 5V ond Vu = ; > pt. ber both - terse CMOS INVERTER B y_A Redrawn Layout from SIMPLer [ (7 Metal (CF) 1 CF=Clear Field, | DF = Dark Field j | xide Mask (DF) @ NOTE! in answering this 3 . N-Well question, put numbers (DF) ONLY on layout, and only letters ” on cross-sections Problem 3 (20 points) You are trying to construct a de switch with an MOS transistor, as shown below. The idea: When input is low, output high. But when input is high, output is hopefully low. p= SV Note: For this transistor Cy, = (OFF /am = 1pF/cm? w= 10005 = for electrons LOAD = 10pf (a) If Vjy = 5V, what is the channel electron charge (coulomb/cm?)(for small values of Voy only)? Qz Cox (Ves- ve) forma Cox (Vee- Vr\ rt value 4S R106 be § 4S (b) If V,,, = 5 V, what is the sheet resistance of the channel? (Again for the case in which V is very small.) IN OUT Ty R= a” formula Y Mb Q * a value 22 2 JL/ q usxio lovo (c) What is the value of Vj, needed x produce an output of 0.1 V? 5v . A Sel > XK Vo vas > Gary vn=_ sv R= Ra rE et D>Ryz 500 W/o Wo? > Nosy = AV te (d) If the input suddenly switches low, and the load is 10 pF, as shown, sketch the output voltage versus time (accurately) and estimate the time At for the output to go from 0.1 V to 2.45V (halfway to 5 V). HALE -WwAY > At=, 6% RC At = 33,8 nsec my Yak lope 5 of 10 wer qd) Vour(Y) p> time t o - Oo + Oo + In ax +m 6 of 10 Problem 5 (20 points) (a) You open up your Robot Kit and find the following circuit. You suspect itis a linear voltage amplifier. You know the differential amplifier has very high internal gain. (a.1) Is it a linearamplifier?. : Vv , (a.2) If so, what is the voltage gain v 7 [Ef not, ignore (a.2).] i (a.3) If-not, why not? 190K Linear amplifier’. Ge} or No) Vv “ oO signal .33.3KQ) +Rajl = 45.2V AVE = EO 0 to +250 mV Rail = 0V i If not, why -not?, aie = 10+10 A Vv —nt "22.0 (b) You also find the following circuit. Again you suspect a a linear amplifier. ‘You know the differential ampli- fier has very high internal gain. (b.1) Is it a linear amplifier? (b.2) If so, what is the voltage gain? [If not, ignore (b.2).] (b.3) If not, why not? 500K signal 0 to +250 mV Linear amplifier?__(Yes orc) v +Rail = 45.2 Ay® v, = Rail = OV ¥f not, why no_t FEED BACK Car RAtLS) (c) Carefully sketch the curve of Your. “versus Vin for circuit (a) on the graph axes provided for OSV, S.250mvV. (@) Carefully sketch the ‘curve of Voyy versus V,,: for circuit (b) on the graph axes provided for OSV, $ 250mV. 9of10 © reer , + Vy(mV) + + ++ ton} + 30 Yoo" 140 200 20 IN @) Ve Me TEMS Mgnt Ve Pa ‘We me Oy x Vat Vea 25 (Gaty, ied Se 1rent PF OF OAV. Wied = cs OAV. ME sel Vy Vour(¥):: 6" 4 Savy ed toe ome 10.0f 10