Determine the differential-mode gain, common-mode gain, differential-mode input resistance, and common-mode input resistance for the circuit of Fig. 3.45 with I_TAIL= 20 µA, R_TAIL= 

10 MΩ, R_C = 100 kΩ, and V_EE = V_CC = 5 V. Neglect r_b, r_o, and r_μ. Calculate the CMRR. Check with SPICE and use SPICE to investigate the effects of adding nonzero r_b and finite V_A as given in Fig. 2.30.

Fig. 3.45:

Fig. 2.30:

+Vcc RC RC Vo2 Vo1 I2 Q2 Q1 Vi2 Vi1 RTAIL ITAIL -VEE ypcal Value, ypical Value, 5-2-cm,17-m epi 1-2-cm,10-m epi 44-V Device 20-V Device Parameter 200 200 Bf 2 2 VA 130 V 90 V 2 x 10-4 5 x 10-15A 10-1A 2.8 x 10-4 1.5 x 10-15 A 10-10 A Is Ico BVCEO BV BVEBO 50 V 25 V 90 V 50 V 7V 0.35 ns 0.25 ns TF 400 ns 200 ns TR Bo 200 150 200 2 200 2 r re (saturation) 200 2 75 2 rex 1.3 pF C je0 1 pF 0.7 V Base-emitter junction 0.7 V 0.33 0.33 ne 0.3 pF 0.6 pF Yoc Base-collector junction 0.55 V 0.6 V 0.5 0.5 3 pF 3 pF Ces0 Vos Collector-substrate junction 0.52 V 0.58 V 0.5 0.5 ns