4.(30%) Consider the BiCMOS amplifier shown in Fig. 4 has= 100 kΩ, RG = 10 MΩ, Rs = 6.8 kΩ, Rc = 3kΩ, RL= 1 kΩ, CI= 0.1 μF, C2 = 1 μF. The BJT has 0.7 V, β = 200, Cμ = 0.8 pF, fT = 600 MHz, and thermal voltage VT= 25 mV. The MOSFET has = 1 V, = 2 mA/V2, and= 1 pF. Neglect the Early effect and channel length modulation effect. (a) Consider the DC bias circuit. Neglect the base current of Q2 in determining the current in Q1. Find the DC drain current in Q1 and collector current in Q2. (b) Consider the circuit at low frequencies. Deternine the frequency of the poles due to C1 and C2. (c) Consider the circuit at higher frequencies. Use open-circuit time constants to estimate fH. (5%,5%,5%,5%,10%)
3.(30%) The amplifier shown in Fig. 3 has =RL = 1 kΩ, Rc= 1 kΩ, RB = 47 kΩ. The
BJT has 0.7 V, β= 100, Cμ = 0.8 pF, fT = 600 MHz, and thermal voltage VT = 25 mV.
Assume the coupling capacitors to be very large. Neglect the Early effect. (a) Find the collector
current of the transistor. (b) Find the overall gain vdvsig and the input resistance at midband
frequency. (c) Find the high frequency response fH. (5%,5%,10%,10%)
2.(20%) Figure 2 shows a BJT circuit with the = 200 kΩ,
RE = 5kΩ, Rc =2 kΩ, RL= 5 kΩ. The BJT has0.7 V, β = 100, thermal voltage VT = 25 mV.
Neglect the Early effect. (a) Please find the DC collector current Ic. (b) For AC analysis, please find
the input resistance Rin, output resistance Rout and overall gain . (5%*4)
(A)L1、L2與L3燈同時明亮 (B)L1、L2與L3燈同時熄滅 (C)L1與L2燈明亮，而L3燈熄滅 (D)L1燈熄滅，而L2與L3燈明亮