Test II Problems Solved - Microelectronic Circuits - Fall 2001 | ECE 3040, Exams of Electrical and Electronics Engineering

Download Test II Problems Solved - Microelectronic Circuits - Fall 2001 | ECE 3040 and more Exams Electrical and Electronics Engineering in PDF only on Docsity! ECE 3040B Microelectronic Circuits Exam 2, Makeup Version July 7, 2001 Dr. W. Alan Doolittle Print your name clearly and largely: Se | u HON Instructions; NOTE: MAKEUP EXAMS ARE DESIGNED TO BE SLIGHTLY HARDER THAN THE ORIGINAL EXAM IN ORDER TO ENCOURAGE EXAM ATTENDANCE! Read ail the problems carefially and thoroughly before you begin working. You are allowed to use 1 new sheet of notes (1 page front and back), your note sheet from the previous exam as well as a calculator. There are 100 total points in this exam. Observe the point value of each problem and allocate your time accordingly. SHOW ALL WORK AND CIRCLE YOUR FINAL ANSWER WITH THE PROPER UNITS INDICATED. Write legibly. If} can not read it, it will be considered to be a wrong answer. Do all work on the paper provided. Turn in all scratch paper, even if it did not lead to an answer. Report any and all ethics violations to the instructor. Good luck! Sign your name on ONE of the two following cases: ] DID.NOT observe any ethical violations during this exam: L observed an ethical violation during this exam:  iext 37% Diode and BJT Semiconductor Physics 1.) (50-points total) As an employee of Texas Instruments Corporation, your boss asks you to design a npn BJT transistor with a DC Common Emitter Current gain, Bpc, greater than 1000 and a high frequency response requiring a very low base-emitter capacitance of 10 pF under the conditions specified below. The transistor will only be used in an amplifier biased into forward active mode with a collector current of | mA and a base-emitter voltage of 0.7 V. a.) (7 points) What are the two contributing sources of capacitance in the emitter- base junction? §Oitussian Capacitance an ' Deflerion Cafac: Fance b.) (8 points) Explain the origin of each of these two sources of capacitance. Ceplatio~ Cap. From maj ority Carriers segerared, by the depletion we dele ,% Difhaustion Cap: Frou pl neni'ty the juncsion, These winerity casriess are Fafemte by the Aeglenton ariderh, ke, c.) (35 points) Design a transistor by specifying doping in the base, emitter, the base quasi-netral region width which will meet the above design criteria given these parameters: Intrinsic concentration n= 1e10 cm? Relative dielectric constant, K, (or €,=11.0 Area= 25,600 um? (160 um x 160 um) Minority carrier diffusion coefficient in the base, Da, in the p side of 15 cm’/Sec Minority carrier diffusion length in the base, Lp, in the p-side of 50 um Minority carrier diffusion coefficient in the emitter, Dg, in the n side of 10 cm?/See Minority carrier diffusion length in the emitter, Lg, in the n-side of 1 um carers injectedacr Answers: Emitter Doping em? Base Doping om? Base Width un Second 50% 2. 2) (56-points) Given the following “video amplifier circuit” and 5 ain, VoutAC/VinAC? Assume: Boc=100, Early voltage is is infinite, tum on nvoages for all forward biased j Junctions are 0.7 V. You may - ‘ge values and are thus, AC shorts, Additional ly ce d at low frequencies where you can neglect a Hf resistances that result from quasi-neutral regions. Hing! Use the Beg model O° Phe evensn ' dethen (RQ fn the Base cireucs, | _ po Rs 50 Vinac fa 100k ce | / S Gin cele Vs <SV we Sogou 7 will asseme Dl is off an DA rs on! Re \ qk Lok sv ay, oe Y rae Rio SV: [kp tod +0 Rio = T= 6u4 exon wel (Mths OT tT Ro = 137 V BV =F oda R OT eh ay BV Rio Vinx L374 RT R Ryn Ra |} Rio * = 1046 J.  Ny OY GIRATTY INCale with problem you are solving. O= 137 -Tglion) -0.1 —(Pr)T> (Rr+te) - tT Cee View R rh L, E Vee Tg G.66uA Vaz Vib- Tg hn > 136 Lee t66aA Uo SV-TeRs 2 Z27V Te em uA Ves = Dae (Rit Ry) = 066 V Facnard Ae «hve mooke is verthhect, —$ Valtages Can EAL Disole a ssamphbas Fmal| sishal made! farameyers 4 ~ gd? Tors — o.eoosig Vr > oaang = 9108 lol = Hi 250 J2 Note. td || Ra 22 S02 $o we have smyteclance > 00334 5 — matohecl rhe SUCK) TaAnimsssion Line, am pte. tbbe-6 VT 6.0054 epee = 2910 JZ You Varies » Te Small signa | Meche. | he done here, but clearly indicate with Fe 4 : problem you are solving Oe > 655 vf t wr 3,) We now need : aah Vez te Rz tar +4 re * Game + Shen ane ‘Ge ae 4, vr | Ve LL Ve, (9m + Ry +1 + x = 0.54 se Ave 2 Nant Now vin ver ah = ‘ TP Ah ain = 127 vie |