Microelectronic Devices and Circuits - EECS 105 Spring 2003 Midterm 1, Exams of Microeconomics

Download Microelectronic Devices and Circuits - EECS 105 Spring 2003 Midterm 1 and more Exams Microeconomics in PDF only on Docsity! Microelectronic Devices and Circuits – EECS 105 Spring 2003 Midterm 1 Professor Costas J. Spanos MOS Device Data (otherwise indicated on the particular problem) (you may not have to use all of these…)
nCox = 50
A/V2,
pCox = 25
A/V2, VTn = -VTp = 1 V, Lmin = 1
m. VBS = 0. n = p = 0.1 V-1 when L = 1
m, and it is otherwise proportional to 1/L Cox = 2.3 fF/
m2. Also: o = 8.85 10-14 F/cm, ox = 3.9 o and si = 11.7 o. Problem 1 of 4: Answer each question briefly and clearly. (5 pts each, 40 total) 1.1 Assume a diffused resistor with a fixed thickness. What happens to the Sheet Resistance (Rs) if the doping level doubles (assuming that there is only a single dopant and that mobility does not change)?  … stays the same  … doubles  … is reduced by 50%  … none of the above 1.2 Find the “built-in potential” B of a junction that has NA = 1016/cm3 and ND = 1017/cm. 1.3 Place check marks where appropriate to indicate the correct region of operation, assuming that VTn = -VTp = 1 V. Transistor VGS VDS VBS Off Triode Saturation NMOS 2 2 0 NMOS 2 0.5 0 PMOS -2 -2 0 PMOS 2 0.5 0 1.4 Choose the most appropriate answer. A negatively charged “depletion” region in doped Si is characterized by …  … an abundance of electrons and negative ions  … too many electrons, too few holes  … a severe imbalance between negative ions and holes  … the complete depletion of charge density 1.5 We have a 2-terminal device that accumulates charge as a function of voltage according to the equation: Q = 5V2 + 3V + 2, where Q is in pico Cb and V is in volts. Find the small signal capacitance of this device in pF at 2V. 1.6 Write the expression of a transfer function that corresponds to the Bode plot drawn. 1.7 The value of a voltage source is 5 + 0.02cos(106t + 45˚) Volts. Please complete the list below: Vs = vs = vs = Problem 3 of 4: Answer each question briefly and clearly. (20 points) Consider the circuit below. Assume R1 = 1M, R2 = 100, and C = 1pF. 3.1 Write the transfer function vout / vin. 3.2 Calculate the gain at DC, the gain at extremely high frequencies ( = infinity), and the numerical values of any poles and/or zeros that this function has. expression value Gain at DC = Gainat  = infinity = Pole 1 = Pole 2 = … Zero 1 = Zero 2 = … Problem 4 of 4: Answer each question briefly and clearly. (20 points) You are given an NMOS transistor, connected as shown. 4.1 Find an expression for W so that the output voltage Vout is 2.5V. Assume n = 0.1 V-1 when L = 1
m, and it is otherwise proportional to 1/L. expression 4.2 Assume R = 10k,
nCox = 50
A/V2, VTn = 1V, n = 0.1 V-1 when L = 1
m, and it is otherwise proportional to 1/L. Find W/L when L is 2
m, and when L is 4
m. value W = W/L when L = 2
m = W/L when L = 4
m =