Chapter 11, Problem 11.60P

The differential amplifier shown in Figure P 11.60 has a pair of pnp bipolars as input devices and a pair of npn bipolars connected as an active load.

The circuit bias is $I_Q=0.2\text{mA},$ and the transistor parameters are $\beta =100$ and $V_A=100\text{V}.$ (a) Determine $I_0$ such that the de currents in the diff-amp are balanced. (b) Find the open-circuit differential-mode voltage gain. (c) Determine the differential-mode voltage gain if a load resistance $R_L=250\text{k}\Omega$ is connected to the output.