lvy>試卷(2022/08/12)

# 103 年 - 103 國立中山大學_碩士班招生考試_電機系(甲、乙、戊組)、電波領域：電子學#110218

【非選題】
1.

1. (25%) Consider an ideal Si p-n diode with abrupt junction at T = 300 K (VT= 25.9 mV) for which the doping concentrations are NA = . The cross-sectional area A = 100 μm2. When this p-n diode is reverse biased with the reverse voltage VR = 1 V, please calculate the depletion width of n-side Wn and p-side Wp, the charge stored on each side of the depletion region QJ, the reverse saturation current Is and the junction capacitance Cj. Let Si intrinsic concentration ni = 1.5 cm , and Si permittivity εsi = 11.7 x 8.85 x F/cm. Diffusion length and diffusion coefficient of electron in p-side are Ln = 10 pum and Dn= 18 cm2/s, respectively. Diffusion length and diffusion coeticient of hole in n-side are Lp = 5 um and Dp = 10 cm2 /s, respectively. (Wn, Wp, QJ, Is, Cj: 5%*5)

【非選題】
2.2. (30%) Figure 1 shows a four-stage bipolar op-amp circuit. If all transistors are operating in the active n with the same B = 100, and VT= 25mV.(1) Please perform an approximate dc analysis PoEl =0.7 V, and neglecting the Early effect) to calculate the quiescent power dissipation in this cireuit, (2) What is the input common mode voltage range of this op-amp? (3) Calculate the voltage gain of the first stage and (4) the overall voltage gain. (5%, 5%, 5%, 15%)

【非選題】
3.

3. (15%) Figure 2 shows a peak rectifier fed by a 100-Hz sinusoid having a peak value Vp = 120 V. The load resistance R = 20 kΩ. The output voltage shows a peal-to-peak ripple of 1.5V. Please calculate (1) the value of the capacitor C, (2) the fraction of the cycle during which the diode is conducting, (3) the average of the diode current. (5%, 5%, 5%)

【非選題】
4.

4.(30%) Figure 3 shows the common-source amplifer with an ideal current source I = 0.4 mA, = 200 kΩ, RG = 2 MΩ, RD =RL = 20 kΩ, C1 = C2 = C3 = 1 HF. The MOSFET has the device parameters: I = 0.2 μm, W = 2 μm, = 10 fP/μm2, μn = 450 cm2/V-s, r0 = 100 kΩ, = 3.2 fF, can be neglected, and the source terminal of MOSFET is connected to its body terminal. Please calculate (1) the transconductance gm of the MOSFET, (2) the AM  f1，f2，f3 (let f1 ＜f2＜f3) values of the overall low- frequency transfer function , (3) the upper 3-dB frequency fr by using open-circuit time constants method. (5%, 5%*4, 5%)

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