EE 2212

PROBLEM SET 12

S. G. Burns

Due: 1 May 2013

(LAST PROBLEM SET!!!)

For Problems 1 and 2. Draw and carefully label your circuits. These are problems where you can exploit symmetry and then can use half-circuit models to simplify the analysis.

1. Text 15.4 BJT Differential Pair Delete the differential-mode and common-mode output resistances.

2. Text 15.25 NMOS Differential Pair

3. Refer to the modified and annotated partial diagram of a Fairchild μA725 operational amplifier IC. Assume all npn BJTS are matched with β = 150 and an Early voltage of V_A = 100 volts. I_C3 = 31 μA. The circuit is connected to ± 12 volt power supplies. Compute the following quantities for this circuit (Observe, you will have to compute a value for R₄):

(a) The differential mode voltage gain, A_dm.

(b) The common-mode current gain, A_cm.

(c) Common-mode rejection ratio, CMRR, numerically and in dB.