申論題

4. (30%) Consider a bipolar active-loaded CE amplifier having the load current source implemented with a pnp transistor, Let the circuit be operating at a 1-mA bias current. The transistors are specified as follows: β(npn) = 200, early voltage V_An = 150 V, |V_Apl = 100 V, C_π = 15 pF, C_µ = 0.4 pF, C_L = 5pF, and base resistance r_x = 200 Ω. The amplifier is fed with a signal source having a resistance of 30 kΩ. Determine (a) midband gain A_M, (b) input capacitor Cin and high-frequency response fH using the Miller effect, (c) f_H using open-circuit time constants, (d) the frequency of the transmission zero f_z,and (e) the gain-bandwidth product. Thermal voltage is 25 mV. (5%*6)