88學年度電子工程學系研究所乙組電子學招生考試命題

私立中原大學八十八學年度研究所招生考試命題紙

所組別 :

電子工程學系乙組

科目 :

電子學

考試時間 :

05月01日第3節

Problem 1 (25%)

For the circuit shown in Fig.1, let b= 100, V_BE(on) = 0.7V, and the Early voltage, V_A = 100V, find the values of the labeled node voltages.

Fig.1

Problem 2 (20%)

For the multi-transistor current source circuit shown in Fig.2, the transistor parameters are V_THN = 1V, m_nC_ox = 50 u A/V², and l = 0 (l :channel length modulation factor). Assume M1, M2, and M3 are identical. Design the circuit and find the (W/L)_M1 and (W/L)_M4 such that Iref = 0.2mA and Io = 0.2mA.

Fig.2

Problem 3 (25%)

Consider the basic MOSFT amplifier with active load shown in Fig.3. The transistor parameters are: V_THN = |V_THP| = 1V, m_nC_ox = 40 u A/V², m_pC_ox = 20uA/V²,λ_N=λ_P = 0.02V^-1

(a)	Assume M1, M2 and M3 are identical and the quiescent input voltage is V_IQ = 2V, the quiescent output voltage is to be V_OQ = 2.5V, design the circuit and find the (W/L)_M1 and (W/L)_M4such that Iref = Io = 100uA.
(b)	Determine the open-circuit small-signal voltage gain.

Fig.3

Problem 4 (30%)

Consider the one-pole low-pass filter shown in Fig.4

(a)	Derive the transfer function of Vo(s) / Vin(s).
(b)	If Cf = 10 pF, determine the value of Rf such that the cutoff frequency f_3dB = 10 kHz. In addition, if a gain of –100 is desired, find the value of R1.
(c)	Draw the equivalent switched-capacitor circuit for replacing the filter shown in Fig.4 Fig.4

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