Refer to Figure 9 $r_{O}=\infty$ Assume $\left|V_{B E}\right|=0.7 \mathrm{~V}$
(A) For 9.10.1

Refer to Figure 9.10.1 below.


Figure 9.10.1
Note: Neglect the Early effect; that is, assume $r_{O}=\infty$ . Assume $\left|V_{B E}\right|=0.7 \mathrm{~V}$ .
(a) For $V_{A}=V_{B}=0 \mathrm{~V}$ and neglecting all base currents, design the circuit of Fig. 9.10.1 so that each of $Q_{1}$ and $Q_{2}$ operates at a dc bias current of $0.25 \mathrm{~mA}, V_{C}=V_{D}=+10 \mathrm{~V}, V_{E}=0 \mathrm{~V}$ , and $Q_{5}$ operates at a dc bias current of $3 \mathrm{~mA}$ . Specify the dc bias current at which each of $Q_{3}$ and $Q_{4}$ will be operating and give the required value of $R_{1}, R_{2}$ , $R_{3}, R_{4}$ , and $R_{5}$ .
(b) If $\beta=99$ , what must the value of each of the two resistances labeled $R_{e}$ be so as to obtain an input differential resistance of $40 \mathrm{k} \Omega$ ?
(c) Find the differential voltage gain of the input stage, $Q_{1}-Q_{2}$ .
(d) Find the voltage gain of the second stage, $Q_{3}-Q_{4}$ .
(e) Find the voltage gain of the output stage, $Q_{5}$ .
(f) Find the overall voltage gain, $v_{e} /\left(v_{b}-v_{a}\right)$ .