The circuit of Fig. P5.15 is known as a currentdifferencing amplifi er because it responds to the difference of its input currents to give vo 5 z(ip 2 in), where z is the transimpedance gain, in V/A....

The circuit of Fig. P5.15 is known as a currentdifferencing amplifi er because it responds to the difference of its input currents to give vo 5 z(ip 2 in), where z is the transimpedance gain, in V/A. The Q1-Q2 mirror reverses the direction of ip so that the current into Q3’s base is ib3 5 in 2 ip, and Q3 is a CE amplifi er whose output is buffered to the load RL by the Darlington-like pair Q4-Q5. (Omitted for simplicity is the circuitry providing the sources V1 and V2 to bias the 200-A current source Q6 and the 1.3-mA current sink Q7). Assuming 3 5 125, 5 5 200, 4 5 50, and VAn 5 VAp 5 100 V, (a) fi nd IB3 to sustain VO 5 5 V; (b) fi nd the voltage gain av 5 voyvb3; (c) fi nd the transimpedance gain z 5 voy(ip 2 in).