Consider the circuit in Figure P11.70, in which the input transistors to the diff-amp are Darlington pairs. Assume transistor parameters of \(\beta(\mathrm{npn})=120, \beta(\mathrm{pnp})=80, V_{A}(\mathrm{npn})=100 \mathrm{~V}\), and \(V_{A}(\mathrm{pnp})=80 \mathrm{~V}\). Let the power supply voltages be \(\pm 10 \mathrm{~V}\) and let \(I_{Q}=1 \mathrm{~mA}\).

(a) Determine the output resistance \(R_{o}\).

(b) Calculate the differential-mode voltage gain.

(c) Find the differential-mode input resistance \(R_{i d}\).

Transcribed Image Text:

Q5 V+ 26 -0% Vi Qi Q3 Q4 Figure P11.70 Q2 Dig