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# 电子电路设计代写 EE 311代写 Electronic Circuit Design代写

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## Practice Exam

### Instructions:

1. This exam is close book, close notes. You may use a calculator but it may not be shared with anyone else during the exam. Devices that can communicate with the outside world are not allowed.
2. Show all work for partial-credit consideration.
3. Express answers in engineering notation to no more than 3 significant digits. Exponents should be a multiple of 3 and written as metric prefixes (p, n, μ, m, k, M, etc.) with units (V, A, Ω, W, etc.)
4. Neat and accurate circuit diagrams and small-signal models are required on exams that conform to IEEE standards for schematic drawings. Label device terminals (ebc or gsdb), components (rπ, RL, etc.), and relevant voltages and currents (vgs, vi, vo, etc.). Indicate connections on schematics with dots, as shown below. Refer to the problem figures for other examples.

### Problem 1电子电路设计代写

[5×3 pts=15 pts]

(a) Multiple choice questions :

(i) In the current mirror shown below, if (W/L)Q2 : (W/L)Q1 = 2:1 and (W/L)Q4 : (W/L)Q3 = 1:2 then I0 is:

(a) I0= Iref

(b) I0 = 2Iref

(c) I0 = 4Iref

(d) I0 = 0.5Iref

(iii) In the following differential amplifier, if VCM=1V then source potential VS is

(a) 0V

(b) -1.5V

(c) -1.0V

(d) -2.0V

(iv) A BJT transistor operating in active mode has IE = 1mA and IB = 10µA, then β is

(a) 990

(b) 100

(c) 99

(d) 1

(v) In the common source amplifier circuits show below the relationship between overdrive voltages (VOV) of CS-x and CS-y is

(a) VOV of CS-y is 4 times than VOV of CS-x

(b) VOV of CS-y is 2 times than VOV of CS-x

(c) VOV of CS-y is same as VOV of CS-x

(d) VOV of CS-y is 0.5 times than VOV of CS-x

### Problem 2电子电路设计代写

[5×4=20 pts]

Consider the FET amplifier shown below for the case VDD =1.8V, VGS = 0.6V, k’n(W/L) = 5mA/V2 , Vt = 0.4V and RD = 10kΩ. Note that VDS is DC bias and vgs is small signal voltage.

(a) Find the DC quantities ID and VDS.

(b) Calculate the value of gm at the bias point

(c) Calculate the value of voltage gain.

(d) If the MOSFET has λ=0.1V-1 , find ro at the bias point and calculate the voltage gain.

### Problem 3电子电路设计代写

[20 pts]

(a) In a MOS cascode amplifier, the cascode transistor is required to raise the output resistance by a factor of 50. If the transistor is operated at VOV =0.2V, what must be its VA be?

(b) Find the gain of the following amplifier in terms of gm and ro of transistors (gm of Q1 is gm1, ro of Q1 is ro1 and so on). (Hint: Think about output resistance of NMOS “Rn” and input resistance of PMOS “Rp”).

### Problem 4

[10+15=25 pts]

In the circuit below ID =100µA, all transistors have VOV =0.5V and VA = 3.6V. (µnCox = 4µpCox = 100µA/V2 ).

(a) Find (W/L) of all transistors.

(b) Find the gain, input and output resistances.

### Problem 5电子电路设计代写

[20 pts]

Given the following data, calculate the Gm, RO and Avo of the amplifier circuit shown below: I =100µA, β=125, W/L=25, VA =1.8V, µnCox = 400µA/V2 .

### Bonus Problem

[10 pts]

Assume Q3 and Q4 as well as Q1 and Q2 are identical and their output resistance is r0. Compute the expression for differential gain.

Hints: (i) You can use half-circuit analysis. (ii) DC nodes can be grounded for small signal analysis.